Subscriber access provided by IDAHO STATE UNIV
Article
Benzylarylation of N-Allyl Anilines: Synthesis of Benzylated Indolines Wenzhong Huang, Xiulan Li, Xuemei Song, Qing Luo, Yanping Li, Ying Dong, Deqiang Liang, and Baoling Wang J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.9b00237 • Publication Date (Web): 25 Apr 2019 Downloaded from http://pubs.acs.org on April 25, 2019
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
Benzylarylation of N-Allyl Anilines: Synthesis of Benzylated Indolines Wenzhong Huang,† Xiulan Li,† Xuemei Song,† Qing Luo,† Yanping Li,† Ying Dong,‡ Deqiang Liang,†,§, and Baoling Wang†,§ †Department
of Chemistry, Kunming University, Kunming 650214, China. of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, China §Yunnan Engineering Technology Research Center for Plastic Films, Kunming 650214, China ‡College
Supporting Information
R1 N PG
R2
MnCl2.4H2O (10 mol%) DTBP (2 equiv) R1
Ar H H
N PG first benzylation across unactivated alkenes with toluene benzylated indolines provided 35 examples exo selective
R2
methyl arenes, 140 °C
ABSTRACT: An unprecedented benzylic C−H functionalization of methyl arenes across unactivated alkenes is presented. In the presence of MnCl24H2O and di-tert-butyl peroxide (DTBP), N-allyl anilines underwent benzylation/cyclization cascade to give benzylated indolines, which are a previously unmet synthetic goal. This protocol features simple operation, broad substrate scope, and great exo selectivity.
INTRODUCTION In the past decade, dehydrogenative C–H functionalization has emerged as a powerful tool for C–C bond construction, and is of fundamental interest in organic chemistry because of remarkable atom- and stepeconomy.1 The inexpensive and abundant hydrocarbon feedstocks are considered ideal C–H sources.2 For example, benzylic C−H functionalization of toluene has been extensively investigated, and its C−C coupling partners include aromatic,3,4 heteroaromatic,5,6 aldehydic,7 activated alkylic,8,9 and activated alkenylic C–H bonds,10,11 as well as C−halogen,12 C−B,13 C−NO2,14 C−CO2H15 and C−COMe bonds,16 and CuIIIbpy(CF3)3.17 Radical addition of benzylic C−H bonds across CO,18 activated alkynes19 or activated alkenes 20,21 has also been developed. In sharp contrast, benzylative coupling or addition of methyl arenes with unactivated alkenes has never been achieved (Scheme 1a). This could be rationalized by polarity mismatching.22 Benzylic radicals5a,d,e,8b,10a,20c,e,g and unactivated alkenes23 are both considered nucleophilic,22 and they tend to react with electron-deficient species.3,5,7,8,10,12-20 The coupling of methyl arene radicals with an electron-rich partner is a formidable challenge. In 2016, Greaney and co-workers reported an in situ bromination protocol to effect the remarkable crossdehydrogenative-coupling reaction of polarity-mismatched alkoxybenzenes with methyl arenes, wherein 2 equiv of CuBr2 were used and still poor yields were observed in
most cases.4 Assisted by a directing group and metal complexation, methyl arene derivatives were also reported to undergo cross-coupling with indoles,6 ferrocenes,24 and unactivated alkylic C–H bonds.25 In 2018, an exciting benzylation of enolates was reported by Yazaki and Ohshima, and the reaction proceeds through dual iron catalyst activation and is 2‑acylimidazole-dependent.8a Since examples of nucleophile benzylation using methyl arenes are rare,11,26 new chemistry needs to be developed. Scheme 1. Background a) Coupling of Unactivated Alkenes with Methyl Arenes Bn H polarity R Bn R mismatching not reported b) This Work: Benzylarylation of Unactivated Alkenes R
1
N PG
MnCl2.4H2O (10 mol%) DTBP (2 equiv) R1
R2
Ar H H
N PG first benzylation across unactivated alkenes with toluene benzylated indolines provided 35 examples exo selective
R2
methyl arenes, 140 °C
c) Synthesis of Benzylated Oxoindoles from N-Arylacrylamides Bn
Bn H N
O
ACS Paragon Plus Environment
[O]
O N
? [H]
N
Bn H H
functional group intolerance
The Journal of Organic Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Interestingly, several electron-rich activated alkenes,27 as well as 2-biphenyl isocyanides,28 have been reported to undergo cascade benzylic radical addition/cyclization sequence, like electron-deficient activated alkenes do,29,30 affording valuable carbo- and heterocyclic products. It is speculated that it might be the cyclization process which permits such polarity-mismatched couplings. Specifically, rapid intramolecular trapping of the transient radicals generated by addition, and related stabilization effect of cyclized intermediates as well as final products, might serve as the thermodynamic reaction driving force. Nevertheless, unactivated alkenes were not involved in such benzylation/cyclization processes either, probably attributed to two major problems: unfavourable polar effect and insufficiently stabilized radicals which might be difficult to trap in situ. In the past decades, activated olefin difunctionalization has proven to be a powerful tool to access molecule complexity,20,21,27,29,30 whereas the difunctionalization across unactivated ones remains more rudimentary.23,31 In continuation of our interest in radical chemistry,32 we wondered whether a challenging benzylation/cyclization sequence of unactivated alkenes could be enabled by the simple combination of an active aryl group and a transition metal salt. The active aryl group might function as both an inbuilt radical trap and an intermediate stabilizer, whereas the metal salt would facilitate final aromaticity restoration process. We examined protected N-allyl anilines as substrates,31,33 and to our delight, this synthetic plan was successful executed, delivering benzylated indolines with broad substrate scope and great exo/endo selectivity (Scheme 1b). To the best of our knowledge, this is the first benzylation reaction across unactivated alkenes with methyl arenes. The indoline is a privileged structural motif found in a broad range of alkaloids and pharmaceuticals.34 Their diverse biological properties and clinical applications in turn demand highly structure-diversified indoline derivatives as drug candidates. In indole chemistry, however, it is significantly more challenging to construct an indoline framework than to elaborate other indolic counterparts such as oxoindole.35 Oxoindoles could be prepared either by the derivatization of their parent indolic variants,36 or through the chemistry of Narylacrylamides (Scheme 1c),29,37 whereas access to indolines is mainly restricted to indole dearomatization reactions.38 Indoline syntheses from acyclic materials are rather limited, and transformation of oxoindoles to indolines suffers from severe functional group intolerance due to the strongly reducing conditions required.39 Our protocol provides a straightforward entry to benzylated indolines.
RESULTS AND DISCUSSION The initial investigations were performed with N-(2methylallyl)-N-phenylacetamide 1a1 as the model substrate (Table 1). To our delight, upon exposure of 1a1 to 2 equiv of di-tert-butyl peroxide (DTBP) in toluene at 140 C, the expected benzylation/cyclization reaction was
Page 2 of 15
Table 1. Optimization of Reaction Conditionsa catalyst, oxidant N Ac 1a1
N Ac 2a1
toluene, 140 °C, 6 h
Bn H H
N Ac 3
Bz H H
entry
catalyst
oxidant
yield of 2a1 (%)
1
none
DTBP
33 (11)b (36)c
2
TBAI
DTBP
55d (24)c
3
CuBr
DTBP
49 (8)b (21)c
4
Cu(OAc)2
DTBP
32 (10)c
5
Cu2O
DTBP
44 (30)c
6
AgNO3
DTBP
55 (8)b (23)c
7
FeCl36H2O
DTBP
56 (trace)b (13)c
8
FeCl24H2O
DTBP
59 (8)b (24)c
9
CoCl26H2O
DTBP
32 (26)c
10
NiCl26H2O
DTBP
58 (9)b (14)c
11
MnCl24H2O
DTBP
70 (56)e (7)b (8)c
12
Mn(OAc)32H2O
DTBP
61 (8)b (12)c
13
MnO2
DTBP
56 (14)b (15)c
14
KMnO4
DTBP
66 (20)c
15
MnCl24H2O
TBHPf
38 (16)b
16
MnCl24H2O
DCP
15
17
MnCl24H2O
BPO
26 (7)b (16)c
18
MnCl24H2O
TBPB
trace
19
MnCl24H2O
K2S2O8
trace (15)c
20g
MnCl24H2O
DTBP
58 (17)b (7)c
21h
MnCl24H2O
DTBP
46-62
aReaction conditions: 1a1 (0.25 mmol), catalyst (0.025 mmol), oxidant (0.5 mmol), toluene (5.0 mL), 140 C, 6 h. bYield of 3. cRecovery of 1a1. dThe same yield was achieved when the reaction was run using 20 mol% TBAI for 12 h. eThe reaction was performed using 5.3 mmol of 1a1. f5.0−6.0 mol/L in decane. gThe reaction was run in 2 mL toluene under otherwise identical conditions. hThe reaction was performed under otherwise identical conditions using 5 mol% MnCl24H2O or 1.5 equiv of DTBP, or at 120 C.
effected, furnishing benzylated indoline 2a1 albeit in a poor yield, along with benzoylated indoline 3 isolated in 11% yield, which might be related to the oxidation of toluene or the initial product 2a1 (entry 1). To improve the reaction efficiency, catalysts which might stabilize transient radicals and/or facilitate single electron transfer (SET) process were screened.40 The use of tetrabutylammonium iodide (TBAI, entry 2) or various metal salts, including CuBr (entry 3), Cu2O (entry 5), AgNO3 (entry 6), FeCl36H2O (entry 7), FeCl24H2O (entry 8), and NiCl26H2O(entry 10), led to better yields of indoline 2a1, while beneficial effect was not observed with Cu(OAc)2 (entry 4) or CoCl26H2O (entry 9). Almost identical results were obtained using 20 mol% TBAI after a prolonged reaction time (note d, entry 2). Manganese salts proved to be superior catalysts (entries 11-14), and use of
2 ACS Paragon Plus Environment
Page 3 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
Table 2. Synthesis of Benzylated Indolines a R
1
N PG 1
H
R1
N H PG 2
methyl arenes, 140 °C
R2 H H
R1 N Ac
2a1, R1 = H, R2 = Bn, 70% 2a2, R1 = Me, R2 = Bn, 68% 2a3, R1 = Br, R2 = Bn, 54% 2a4, R1 = Cl, R2 = Bn, 60% 2a5, R1 = Ph, R2 = Bn, 46% 2a6, R1 = OMe, R2 = Bn, 52% 2a7, R1 = CF3, R2 = Bn, 41% 4, R1 = CN, R2 = Me, 12%
Bn H 2c H 72%
Bn H H
N COEt
Bn H H
N COR2
N Ac 2b, 53%
Bn H H
Cl
N SO2Et
2e, 46%
N
2d1, R2 = nC7H15, 54% 2d2, R2 = nC9H19, 55% 2d3, R2 = nC11H23, 66% 2d4, R2 = nC17H35, 57% 2d5, R2 = t-Bu, 60%
Bn H H
Cl
N Boc
Bn H H
N COR2 2g, R2 = nC7H15, 41% Cl
2f, 27%
Ar
Ar
Bn H H
R1
Ar
MnCl2.4H2O (10 mol%) DTBP (2 equiv)
H H
N COEt
N CO(CH2)6CH3
2h1, Ar = 2-MePh, 62% R1 = Me, 0% R1 = Cl, 0% (2c, 22%) 2h2, Ar = 3-MePh, 51% 2h3, Ar = 4-MePh, 45% 2
2
N CO(CH2)6CH3
F N COEt 2k, 76%
2j, 60% Ph
H N H COEt 2i1, Ar = 2-ClPh, 81% 2i2, Ar = 3-ClPh, 66% 2i3, Ar = 4-ClPh, 64% 2i4, Ar = 4-FPh, 50% F F F F
Ph
Bn Cl
N COEt
N COEt trace amounts of unidentified products
N Ac
conditions: 1 (0.25 mmol), MnCl24H2O (0.025 mmol), DTBP (0.5 mmol), solvent (5.0 mL), 140 C, 6 h.
aReaction
MnCl24H2O gave the highest yield of 70% (entry 11). Comparison of a series of oxidants was also conducted. Whereas poor yields of indoline 2a1 were afforded using tert-butyl hydroperoxide (TBHP, entry 15), dicumyl peroxide (DCP, entry 16), or benzoyl peroxide (BPO, entry 17), tert-butyl peroxybenzoate (TBPB, entry 18) and K2S2O8 (entry 19) proved ineffective for this transformation. When the reaction was performed in 2 mL toluene under otherwise identical conditions, the yield of indoline 2a1 was compromised (entry 20). Both reducing the loading of the catalyst or DCP, and lowering the reaction temperature, led to diminished yields (entry 21). It is worthy of notice that this synthesis could be carried out on a gram scale with only a slight loss of activity (note e, entry 11), rendering it highly practical. In all these reactions, benzoylated product 3 was produced in very
poor yields, thus we focused our studies on the synthesis of benzylated indolines 2. The optimized conditions were then tested on a broad collection of allylated anilines (Table 2). 5-Substituted indolines 2a2-6 were prepared in 46-68% yields from N(2-methylallyl) acetanilides bearing a methyl, bromo, chloro, phenyl, or methoxy group at the para position of the N-aryl group. Substrates with an electron-deficient Naryl group are less reactive, and 5-trifluoromethyl indoline 2a7 was produced in a poor yield. In the case of cyanosubstituted N-allylated acetanilide, the methyl radical derived from DTBP underwent methylarylation to afford 3-ethyl indoline 4 in 12% yield as the only product. Notably, this method tolerates allylated N-(pyridin-4yl)acetamide, and the corresponding 2,3-dihydro pyrrolo[3,2-c]pyridine product 2b was furnished in 53% yield. While propionyl-protected indoline 2c was also delivered in a good yield, slightly diminished yields were obtained when pivaloyl or long-chain N-protecting groups (PGs), such as octanoyl, decanoyl, dodecanoyl, and stearoyl, were used (2d1-5), probably due to steric conflict. The allylated aniline with a tert-butyloxy-carbonyl PG reacted with toluene to afford indoline 2e in a moderate yield, whereas N-ethylsulfonyl indoline 2f was produced in only a poor yield. The anilide derived from 3,5-dichloroaniline was compatible with this transformation as well, giving the expected benzylated indoline 2g albeit in a modest yield. Ortho-substituted anilides proved to be challenging substrates due to steric hindrance, and the corresponding indoline products were not produced. Instead, severe substrate decomposition was observe. Interestingly, in the case of the ortho-chlorinated anilide, intramolecular aromatic substitution occurred, furnishing arylunsubstituted indoline 2c in 22% yield. As for C−H coupling partners, methyl arenes with an electrondonating or -withdrawing group at the para, meta, or ortho position all worked well in this reaction to furnish the corresponding benzylated indolines 2h-i. Reactions run in ortho-substituted methyl arenes gave the highest yields, whereas methyl arenes with a para-substituent were the most unfavourable C−H sources, the origin of which is unclear at this time. Benzylarylations using mesitylene or 2,3,4,5,6-pentafluorotoluene as the solvent also proceeded smoothly, affording indolines 2j,k in moderate to high yields. To our disappointment, reactions performed in ethylbenzene or cumene, as well as the benzylarylation of a 1,2-disubstituted alkene, hardly occurred, probably due to steric hindrance. Unfortunately, no reaction occurred with aroylprotected allylated anilines even at an elevated temperature (Scheme 2a), which might be attributed to polarity mismatching during cyclizative radical trapping process as a result of -conjugation effect. These results further suggest that an inbuilt radical scavenger with matched electronic property which enables the rapid intramolecular radical trapping is the key for the title reaction. Allylated N-methylbenzamide, however, could undergo a similar benzylarylation reaction to afford 3,4-
3 ACS Paragon Plus Environment
The Journal of Organic Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
dihydroisoquinolin-1-ones 3a,b, albeit in lower yields (Scheme 2b). Scheme 2. Synthesis dihydroisoquinolin-1-ones a)
O
Benzylated
MnCl2.4H2O (10 mol%) DTBP (2 equiv)
R
N Tol
of
3,4-
nr
toluene, 160 °C, 6 h
R = H or Cl b)
O
O
MnCl2.4H2O (10 mol%) DTBP (2 equiv)
N
N Ar
methyl arenes, 140 °C, 6 h
5a, Ar = Ph, 50% 5b, Ar = 2-MePh, 38%
Table 3. Benzylarylation of Non-Methyl-Branched Allyl Anilides a Bn 1
R standard N PG
H
R1
conditions
H
R1
N PG 6, 5-exo-trig
H H
Bn R1 N PG formal 6-endo-trig not detected H
Bn H H
N Ac 6a, R1 = H, 50% 1 6b, R = Me, 57% 6c, R1 = Cl, 62%
Bn H H
N COR2 6d, R2 = Et, 60% 6e, R2 = nC7H15, 46%
R2
N Ac Ph
N Ac complex
MnCl2 4H2O (10 mol%) DTBP (2 equiv) toluene, 140 °C
Bn H H
Cl
MeO2C N Ac 7, 55%
Bn H H
R1
a) 1a1
R2
N Ac
b) BHT
conditions: substrate (0.25 mmol), MnCl24H2O (0.025 mmol), DTBP (0.5 mmol), toluene (5.0 mL), 140 C, 6 h.
aReaction
In light of Baldwin's rules,41 exo- and endo-mode cyclizations are both favoured here, thus our initial studies focused on the benzylarylation of 2-methylallyl anilides in order to avoid the latter mode ring closure. Inspired by the exo selectivity achieved in all of the above reactions, we wondered whether the non-methyl-branched allyl anilides would be suitable substrates (Table 3). We were pleased to find that subjecting such unactivated alkenes having an electron-neutral, -rich, or -deficient N-aryl group to our
5, 71%
Cl toluene/toluene-d8 (1:1, v/v)
2a4 2a4-d7 otherwise standard conditions 46% 0%
N Ac
Cl toluene-d8 otherwise standard conditions
2a4-d7, 0%
D 1a1-d5
D
D standard conditions
N Ac
D
39%, KIE = 1
PhCH3 t-BuOH
1a1
PhCH2
2 t-BuO t-BuO Mn2+ Ac N
H Bn B
2a1 + 2a1-d4
D
f)
Bn H H
N Ac 8, R2 = Br, 67%
5, 28% Bn
t-Bu
standard conditions
c)
1a1 +
O
2a1, 0%
standard conditions
DTBP
Bn
t-Bu
TEMPO (3 equiv) or BHT (2 equiv)
e)
Table 4. Benzylarylation of Anilides with an Activated Allyl Moiety a .
Scheme 3. Mechanistic Investigations
N Ac
conditions: substrate (0.25 mmol), MnCl24H2O (0.025 mmol), DTBP (0.5 mmol), toluene (5.0 mL), 140 C, 6 h.
R
optimized conditions afforded benzylated indolines 4a-e in 46-62% yields. Still, formal 6-endo-trig product was not observed. Anilides having an activated N-allyl moiety were also tested (Table 4). While the reaction of 2-phenylallyl acetanilide led to complex mixtures, from which we failed to isolate any pure product, the ester group-activated substrate33 reacted to furnish methyl indoline-3carboxylate 7 in 55% yield. Interestingly, when 2bromoallyl acetanilide was used, aromatized indole product 8 was delivered in 67% yield, which might arise from the HBr elimination of the initial indoline product.
d)
aReaction
1
Page 4 of 15
Ac
N Bn
t-BuO A
Mn+ Ac N
H Bn
2a1 t-BuOH
C
Radical trapping experiments were performed to confirm the radical nature of this cyclizative benzylation (Scheme 3a). As might be expected, the model reaction under optimized conditions was completely suppressed by doping with either 3 equiv of 2,2,6,6tetramethylpiperidine-1-oxyl (TEMPO) or 2 equiv of 2,6di-tert-butyl-4-methylphenol (BHT). Furthermore, benzylBHT adduct 5 was isolated in 28% yield in the BHT experiment, and subjecting BHT to our optimized conditions afforded the same adduct as the only product in 71% yield (Scheme 3b). These suggested that methyl arene radicals might be involved in this transformation. An intermolecular competing kinetic isotope effect (KIE) experiment was carried out using a toluene/toluene-d8
4 ACS Paragon Plus Environment
Page 5 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
mixture (1:1, v/v, Scheme 3c). Interestingly, deuterated indoline 2a4-d7 was not observed, and a control experiment confirmed that the title benzylation did not proceed in perdeuterated toluene (Scheme 3d), suggesting that the cleavage of the benzylic C–H bond might be a rateinfluencing step. A mixture of the substrates 1a1 and 1a1d5 (1:1) was subjected to the standard conditions, and a neglectable KIE was observed (Scheme 3e), indicating that the C–H bond cleavage of anilines is not involved in the rate-limiting step. On the basis of the above results and previous reports,2730 a tentative mechanistic pathway was proposed (Scheme 3f). At the beginning, tert-butoxyl radical was generated by thermal decomposition of DTBP. Hydrogen atom transfer from a benzylic C–H bond to this radical affords a methyl arene radical, addition of which across the tethered double bond leads to radical intermediate A possessing a newly formed C–C bond. Rapid intramolecular radical trapping by the N-aryl group ensues, furnishing ring closure intermediate B. Subsequent single-electron transfer from B to Mn2 affords cationic intermediate C as well as Mn. Finally, deprotonation of C gives the benzylated indoline 2a1. Mn is oxidized to Mn2 by tert-butoxyl radical to finish the catalytic cycle.
CONCLUSIONS To conclude, a benzylarylation reaction of N-allyl anilines has been developed. This is the first benzylic C−H functionalization of methyl arenes across unactivated alkenes, which provides a direct and straightforward access to benzylated indolines. This protocol features broad substrate scope and simple operation, and exoselectivity was always achieved even using non-methylbranched allyl anilines.
EXPERIMENTAL SECTION General. Chemicals were all purchased from commercial sources and used without treatment. Reactions were monitored by Thin Layer Chromatography (TLC) using silica gel F254 plates. Products were purified by column chromatography over 300-400 mesh silica gel. 1H NMR, 19F NMR, 13C NMR and DEPT NMR spectra were recorded at 25 C on a Bruker AscendTM 400 spectrometer using TMS as internal standard. The term "stack" is used to describe a region where resonances arising from nonequivalent nuclei are coincident, and multiplet, m, to describe a region where resonances arising from a single nucleus (or equivalent nuclei) are coincident but coupling constants cannot be readily assigned. High-resolution mass spectra (HRMS) were obtained using a Bruker microTOF II Focus spectrometer (ESI). Synthesis of Benzylated Indolines and 3,4dihydroisoquinolin-1-ones. To a screw-capped vial with a magnetic stirring bar were added N-allylated amines 1 (0.25 mmol), MnCl24H2O (5 mg, 0.025 mmol), DTBP (73 mg, 0.50 mmol) and methylarene solvent (5.0 mL) under argon. The mixture was stirred at 140 C (oil bath temperature) for 6 h, then it was quenched with saturated aqueous Na2S2O3 (1.0 mL) and water (10.0 mL), and
extracted with CH2Cl2 (10.0 mL) three times. The residue obtained after evaporation of the organic solvent was purified by column chromatography on silica gel using petroleum ether and ethyl acetate as the eluent to give benzylated indolines 2. 2a1, 1-(3-methyl-3-phenethylindolin-1-yl)ethan-1-one, 1:5 mixture of rotamers due to the slow rotation of the N– (CO) bond,42 isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 70% yield (49 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.42 (s, 3H), 1.90-2.03 (m, 2H), 2.17 (s, 3H), 2.39-2.46 (m, 1H), 2.52-2.60 (m, 1H), 3.71 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 7.06-7.27 (m, 8H), 8.22 (d, J 8.0 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.7, 142.3, 141.8, 138.6, 128.5, 128.3, 128.0, 126.0, 123.9, 122.3, 117.0, 61.2, 43.7, 43.4, 31.1, 27.3, 24.3; HRMS (ESI-TOF) Calcd for C19H22NO ([MH]) 280.1696. Found 280.1695. 2a1-d4, 1-(3-methyl-3-phenethylindolin-1-yl-4,5,6,7d4)ethan-1-one, 1:5 mixture of rotamers, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 40% yield (28 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.42 (s, 3H), 1.87-2.05 (m, 2H), 2.17 (s, 3H), 2.39-2.44 (m, 1H), 2.52-2.60 (m, 1H), 3.71 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 7.10 (d, J 7.0 Hz, 2H), 7.17 (dd, J 7.3, 7.3 Hz, 1H), 7.26 (dd, J 8.1, 6.6 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 168.6, 142.2, 141.8, 138.5, 128.5, 128.2, 126.0, 61.2, 43.7, 43.4, 31.1, 27.2, 24.2; HRMS (ESI-TOF) Calcd for C19H18D4NO ([MH]) 284.1947. Found 284.1944. 2a2, 1-(3,5-dimethyl-3-phenethylindolin-1-yl)ethan-1one, 1:4 mixture of rotamers, isolated by flash column chromatography (petroleum ether/ethyl acetate 24:1) in 68% yield (50 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.40 (s, 3H), 1.88-2.01 (m, 2H), 2.15 (s, 3H), 2.33 (s, 3H), 2.39-2.48 (m, 1H), 2.52-2.60 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.87 (d, J 10.3 Hz, 1H), 6.93 (s, 1H), 7.02 (d, J 8.5 Hz, 1H), 7.10 (d, J 7.2 Hz, 2H), 7.16 (dd, J 7.2, 7.2 Hz, 1H), 7.25 (dd, J 7.5, 7.3 Hz, 2H), 8.09 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl ) 168.3, 141.8, 140.0, 3 138.7, 133.4, 128.5, 128.4, 128.2, 126.0, 122.9, 116.7, 61.4, 43.6, 43.3, 31.1, 27.2, 24.1, 21.2; HRMS (ESI-TOF) Calcd for C20H24NO ([MH]) 294.1852. Found 294.1864. 2a3, 1-(5-bromo-3-methyl-3-phenethylindolin-1yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 24:1) in 54% yield (48 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.41 (s, 3H), 1.88-2.02 (m, 2H), 2.15 (s, 3H), 2.40-2.48 (m, 1H), 2.52-2.60 (m, 1H), 3.70 (d, 10.3 Hz, 1H), 3.88 (d, J 10.3 Hz, 1H), 7.11 (d, J 7.1 Hz, 2H), 7.18 (dd, J 7.2, 7.2 Hz, 1H), 7.22-7.29 (m, 3H), 7.33 (dd, J 2.0, 8.6 Hz, 1H), 8.10 (d, J 8.6 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.7, 141.4, 141.3, 141.0, 130.9, 128.5, 128.2, 126.1, 125.6, 118.4, 116.2, 61.2, 43.8, 43.2, 31.0, 27.2, 24.1; HRMS (ESI-TOF) Calcd for C19H21BrNO ([MH]) 358.0801. Found 358.0799. 2a4, 1-(5-chloro-3-methyl-3-phenethylindolin-1yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 24:1) in 60% yield (47
5 ACS Paragon Plus Environment
The Journal of Organic Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.41 (s, 3H), 1.89-2.02 (m, 2H), 2.15 (s, 3H), 2.40-2.48 (m, 1H), 2.52-2.60 (m, 1H), 3.71 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 7.08 (d, J 2.0 Hz, 1H), 7.11 (d, J 7.0 Hz, 2H), 7.16-7.20 (m, 2H), 7.25-7.28 (m, 2H), 8.15 (d, J 8.6 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.7, 141.4, 140.9, 140.6, 128.7, 128.5, 128.2, 128.0, 126.1, 122.7, 118.0, 61.3, 43.8, 43.2, 31.0, 27.2, 24.1; HRMS (ESI-TOF) Calcd for C19H21ClNO ([MH]) 314.1306. Found 314.1298. 2a5, 1-(3-methyl-3-phenethyl-5-phenylindolin-1yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 30:1) in 46% yield (41 mg), white solid: mp 137-138 C. 1H NMR (400 MHz, CDCl3) 1.48 (s, 3H), 1.95-2.08 (m, 2H), 2.19 (s, 3H), 2.45-2.53 (m, 1H), 2.57-2.65 (m, 1H), 3.76 (d, J 10.3 Hz, 1H), 3.94 (d, J 10.3 Hz, 1H), 7.12 (d, J 7.0 Hz, 2H), 7.17 (dd, J 7.3, 7.2 Hz, 1H), 7.24-7.28 (m, 2H), 7.30-7.35 (m, 2H), 7.43 (dd, J 7.8, 7.4 Hz, 2H), 7.48 (dd, J 1.8, 8.4 Hz, 1H), 7.58 (d, J 7.4 Hz, 2H), 8.27 (d, J 8.4 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.6, 141.71, 141.66, 141.0, 139.3, 137.1, 128.8, 128.5, 128.3, 127.00, 126.96, 126.9, 126.0, 121.0, 117.1, 61.5, 43.8, 43.4, 31.1, 27.3, 24.2; HRMS (ESI-TOF) Calcd for C25H26NO ([MH]) 356.2009. Found 356.2012. 2a6, 1-(5-methoxy-3-methyl-3-phenethylindolin-1yl)ethan-1-one, 1:5 mixture of rotamers, isolated by flash column chromatography (petroleum ether/ethyl acetate 15:1) in 52% yield (40 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.41 (s, 3H), 1.85-2.01 (m, 2H), 2.15 (s, 3H), 2.40-2.47 (m, 1H), 2.53-2.61 (m, 1H), 3.70 (d, J 10.3 Hz, 1H), 3.80 (s, 3H), 3.88 (d, J 10.3 Hz, 1H), 6.69 (d, J 2.5 Hz, 1H), 6.76 (dd, J 2.6, 8.7 Hz, 1H), 7.11 (d, J 7.1 Hz, 2H), 7.17 (dd, J 7.3, 7.3 Hz, 1H), 7.26 (dd, J 7.8, 7.0 Hz, 2H), 8.14 (d, J 8.8 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 167.9, 156.5, 141.7, 140.3, 136.1, 128.5, 128.2, 126.0, 117.6, 112.1, 108.9, 61.4, 55.7, 43.8, 43.3, 31.1, 27.2, 24.0; HRMS (ESI-TOF) Calcd for C20H24NO2 ([MH]) 310.1802. Found 310.1806. 2a7, 1-(3-methyl-3-phenethyl-5(trifluoromethyl)indolin-1-yl)ethan-1-one, 1:5 mixture of rotamers, isolated by flash column chromatography (petroleum ether/ethyl acetate 12:1) in 41% yield (36 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.45 (s, 3H), 1.92-2.08 (m, 2H), 2.18 (s, 3H), 2.40-2.48 (m, 1H), 2.53-2.61 (m, 1H), 3.75 (d, J 10.3 Hz, 1H), 3.94 (d, J 10.3 Hz, 1H), 7.10 (d, J 7.1 Hz, 2H), 7.18 (dd, J 7.3, 7.3 Hz, 1H), 7.27 (dd, J 7.5, 7.2 Hz, 2H), 7.35 (s, 1H), 7.50 (dd, J 0.8, 8.5 Hz, 1H), 8.30 (d, J 8.4 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 169.2, 145.0, 141.2, 139.4, 128.6, 128.2, 126.6 (q, 1J(C–F) 274.3 Hz), 126.2, 125.75 (q, 3J(C–F) 3.3 Hz), 119.42 (q, 3J(C–F) 3.1 Hz), 116.7, 61.3, 43.7, 43.2, 31.0, 27.2, 24.3; 19F NMR (376 MHz, CDCl3) –61.52 (s, 3F); HRMS (ESI-TOF) Calcd for C20H21F3NO ([MH]) 348.1570. Found 348.1567. 2b, 1-(3-methyl-3-phenethyl-2,3-dihydro-1Hpyrrolo[3,2-c]pyridin-1-yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 1:1) in 53% yield (37 mg), yellow oil. 1H NMR (400 MHz,
Page 6 of 15
CDCl3) 1.39 (s, 3H), 1.87-1.99 (m, 2H), 2.09 (s, 3H), 2.35-2.53 (m, 2H), 3.64 (d, J 10.2 Hz, 1H), 3.81 (d, J 10.2 Hz, 1H), 7.02 (d, J 7.1 Hz, 2H), 7.09 (dd, J 7.2, 7.2 Hz, 1H), 7.18 (dd, J 7.5, 7.2 Hz, 2H), 7.94 (d, J 4.9 Hz, 1H), 8.28 (s, 1H), 8.34 (d, J 5.3 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.7, 148.9, 147.8, 143.3, 140.1, 132.9, 127.5, 127.2, 125.1, 110.3, 60.3, 42.2, 42.1, 30.0, 26.3, 23.2; HRMS (ESI-TOF) Calcd for C18H21N2O ([MH]) 281.1648. Found 281.1659. 2c, 1-(3-methyl-3-phenethylindolin-1-yl)propan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 75:1) in 72% yield (53 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.22 (t, J 7.4 Hz, 3H), 1.42 (s, 3H), 1.89-2.00 (m, 2H), 2.33-2.46 (m, 3H), 2.51-2.59 (m, 1H), 3.69 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 7.05-7.11 (m, 3H), 7.13-7.18 (m, 2H), 7.21-7.27 (m, 3H), 8.25 (d, J 8.1 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 172.0, 142.5, 141.8, 138.5, 128.5, 128.2, 128.0, 126.0, 123.7, 122.3, 116.9, 60.3, 43.7, 43.5, 31.1, 29.2, 27.2, 8.7; HRMS (ESI-TOF) Calcd for C20H24NO ([MH]) 294.1852. Found 294.1864. 2d1, 1-(3,5-dimethyl-3-phenethylindolin-1-yl)octan-1one, isolated by flash column chromatography (petroleum ether/ethyl acetate 90:1) in 54% yield (51 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 6.8 Hz, 3H), 1.26-1.36 (m, 8H), 1.40 (s, 3H), 1.68-1.75 (m, 2H), 1.872.00 (m, 2H), 2.29-2.48 (m, 6H), 2.52-2.60 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.88 (d, J 10.3 Hz, 1H), 6.92 (s, 1H), 7.02 (d, J 8.5 Hz, 1H), 7.10 (d, J 7.1 Hz, 2H), 7.16 (dd, J 7.4, 7.2 Hz, 1H), 7.25 (dd, J 7.0, 7.7 Hz, 2H), 8.12 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.1, 141.9, 140.2, 138.7, 133.3, 128.5, 128.4, 128.3, 125.9, 122.9, 116.7, 60.6, 43.6, 43.4, 36.0, 31.8, 31.1, 29.4, 29.2, 27.2, 24.7, 22.7, 21.2, 14.1; HRMS (ESI-TOF) Calcd for C26H36NO ([MH]) 378.2791. Found 378.2791. 2d2, 1-(3,5-dimethyl-3-phenethylindolin-1-yl)decan-1one, isolated by flash column chromatography (petroleum ether/ethyl acetate 90:1) in 55% yield (56 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 7.0 Hz, 3H), 1.27-1.36 (m, 12H), 1.40 (s, 3H), 1.68-1.75 (m, 2H), 1.872.00 (m, 2H), 2.26-2.48 (m, 6H), 2.52-2.60 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 6.92 (s, 1H), 7.03 (d, J 8.4 Hz, 1H), 7.11 (d, J 7.0 Hz, 2H), 7.16 (dd, J 7.3, 7.3 Hz, 1H), 7.25 (dd, J 7.6, 7.1 Hz, 2H), 8.12 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.2, 141.9, 140.2, 138.7, 133.3, 128.5, 128.4, 128.2, 125.9, 122.9, 116.7, 60.6, 43.6, 43.4, 36.0, 31.9, 31.1, 29.52, 29.46, 29.3, 27.1, 24.7, 22.7, 21.2, 14.1; HRMS (ESI-TOF) Calcd for C28H40NO ([MH]) 406.3104. Found 406.3108. 2d3, 1-(3,5-dimethyl-3-phenethylindolin-1-yl)dodecan1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 90:1) in 66% yield (72 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 7.0 Hz, 3H), 1.26-1.38 (m, 16H), 1.40 (s, 3H), 1.68-1.75 (m, 2H), 1.87-2.00 (m, 2H), 2.27-2.46 (m, 6H), 2.52-2.60 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 6.92 (s, 1H), 7.03 (d, J 8.4 Hz, 1H), 7.11 (d, J 7.0 Hz, 2H), 7.16
6 ACS Paragon Plus Environment
Page 7 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
(dd, J 7.3, 7.3 Hz, 1H), 7.25 (dd, J 7.6, 7.2 Hz, 2H), 8.11 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.2, 141.9, 140.2, 138.7, 133.3, 128.5, 128.4, 128.2, 125.9, 122.9, 116.7, 60.6, 43.6, 43.4, 36.0, 31.9, 31.1, 29.7, 29.64, 29.56, 29.53, 29.46, 29.4, 27.1, 24.7, 22.7, 21.2, 14.1; HRMS (ESITOF) Calcd for C30H44NO ([MH]) 434.3417. Found 434.3419. 2d4, 1-(3,5-dimethyl-3-phenethylindolin-1yl)octadecan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 95:1) in 57% yield (74 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 7.0 Hz, 3H), 1.25-1.36 (m, 28H), 1.40 (s, 3H), 1.68-1.75 (m, 2H), 1.87-2.00 (m, 2H), 2.29-2.49 (m, 6H), 2.52-2.60 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 6.92 (s, 1H), 7.03 (d, J 8.4 Hz, 1H), 7.11 (d, J 7.0 Hz, 2H), 7.16 (dd, J 7.3, 7.3 Hz, 1H), 7.25 (dd, J 7.6, 7.1 Hz, 2H), 8.11 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.1, 141.9, 140.2, 138.7, 133.3, 128.5, 128.4, 128.2, 125.9, 122.9, 116.7, 60.6, 43.6, 43.4, 36.0, 31.9, 31.1, 29.71, 29.67, 29.6, 29.52, 29.46, 29.4, 27.1, 24.7, 22.7, 21.2, 14.1; HRMS (ESI-TOF) Calcd for C36H56NO ([MH]) 518.4356. Found 518.4352. 2d5, 1-(3,5-dimethyl-3-phenethylindolin-1-yl)-2,2dimethylpropan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 60% yield (50 mg), white solid: mp 59-60 C. 1H NMR (400 MHz, CDCl3) 1.36 (s, 9H), 1.38 (s, 3H), 1.84-1.99 (m, 2H), 2.33 (s, 3H), 2.44-2.51 (m, 1H), 2.59-2.66 (m, 1H), 3.85 (d, J 10.2 Hz, 1H), 4.11 (d, J 10.2 Hz, 1H), 6.93 (s, 1H), 7.02 (d, J 7.8 Hz, 1H), 7.11 (d, J 7.2 Hz, 2H), 7.16 (dd, J 7.4, 7.2 Hz, 1H), 7.25 (dd, J 7.7, 7.0 Hz, 2H), 8.10 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 176.1, 141.9, 141.6, 138.5, 133.4, 128.5, 128.3, 128.2, 126.0, 122.6, 118.2, 61.9, 44.2, 42.5, 40.1, 31.2, 27.7, 25.4, 21.1; HRMS (ESI-TOF) Calcd for C23H30NO ([MH]) 336.2322. Found 336.2322. 2e, tert-butyl 3,5-dimethyl-3-phenethylindoline-1carboxylate, 1:1 mixture of rotamers due to the slow rotation of the N–(CO) bond, isolated by flash column chromatography (petroleum ether/ethyl acetate 300:1) in 46% yield (40 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.36 (s, 3H), 1.57 (s, 9H), 1.83-1.96 (m, 2H), 2.31 (s, 3H), 2.35-2.43 (m, 1H), 2.56-2.63 (m, 1H), 3.64 (brs, 1H), 3.86 (brs, 0.5H), 3.94 (brs, 0.5H), 6.90 (s, 1H), 6.99 (d, J 7.7 Hz, 1H), 7.12 (d, J 7.2 Hz, 2H), 7.15 (dd, J 7.3, 7.3 Hz, 1H), 7.25 (dd, J 7.6, 7.2 Hz, 2H), 7.33 (brs, unexchangeable, 0.5H), 7.73 (brs, unexchangeable, 0.5H); 13C{1H} NMR (100 MHz, CDCl ) 152.5 (br), 142.2, 140.03 138.4 (brm), 131.8, 128.4, 128.3, 125.8, 123.3 (br), 123.1 (br), 114.4, 81.4 (br), 80.4 (br), 60.1 (br), 59.8 (br), 43.6, 42.9 (br), 42.2 (br), 31.0, 28.5, 27.2, 21.0; HRMS (ESI-TOF) Calcd for C23H30NO2 ([MH]) 352.2271. Found 352.2273. 2f, 5-chloro-1-(ethylsulfonyl)-3-methyl-3phenethylindoline, isolated by flash column chromatography (petroleum ether/ethyl acetate 30:1) in 27% yield (25 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.41 (s, 3H), 1.42 (t, J 7.4 Hz, 3H), 1.86-2.01 (m, 2H), 2.40-2.47 (m, 1H), 2.62-2.70 (m, 1H), 3.12 (q, J 7.4 Hz,
2H), 3.73 (d, J 10.1 Hz, 1H), 3.98 (d, J 10.1 Hz, 1H), 7.09 (d, J 2.1 Hz, 1H), 7.12 (d, J 7.0 Hz, 2H), 7.15-7.20 (m, 2H), 7.25-7.27 (m, 2H), 7.30 (d, J 8.5 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 141.3, 140.4, 140.1, 128.54, 128.45, 128.20, 128.18, 126.1, 123.6, 114.1, 62.0, 44.2, 43.9, 42.8, 31.0, 26.5, 7.8; HRMS (ESI-TOF) Calcd for C19H23ClNO2S ([MH]) 364.1133. Found 364.1131. 2g, 1-(4,6-dichloro-3-methyl-3-phenethylindolin-1yl)octan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 100:1) in 41% yield (44 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.89 (t, J 7.0 Hz, 3H), 1.30-1.37 (m, 8H), 1.52 (s, 3H), 1.67-1.74 (m, 2H), 1.89-1.99 (m, 1H), 2.24-2.51 (m, 5H), 3.70 (d, J 10.3 Hz, 1H), 3.93 (d, J 10.3 Hz, 1H), 7.01 (d, J 1.8 Hz, 1H), 7.11 (d, J 7.0 Hz, 2H), 7.17 (dd, J 7.3, 7.3 Hz, 1H), 7.26 (dd, J 7.3, 7.3 Hz, 2H), 8.31 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.8, 145.3, 141.4, 134.4, 132.0, 130.4, 128.5, 128.3, 126.1, 124.7, 116.0, 60.8, 45.3, 40.3, 36.1, 31.7, 31.5, 29.3, 29.2, 26.4, 24.4, 22.7, 14.1; HRMS (ESI-TOF) Calcd for C25H32Cl2NO ([MH]) 432.1855. Found 432.1871. 2h1, 1-(3,5-dimethyl-3-(2-methylphenethyl)indolin-1yl)octan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 50:1) in 62% yield (61 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 7.0 Hz, 3H), 1.30-1.40 (m, 8H), 1.41 (s, 3H), 1.68-1.78 (m, 2H), 1.80-1.91 (m, 2H), 2.20 (s, 3H), 2.27-2.42 (m, 6H), 2.52-2.59 (m, 1H), 3.73 (d, J 10.3 Hz, 1H), 3.95 (d, J 10.3 Hz, 1H), 6.94 (s, 1H), 6.99-7.12 (m, 5H), 8.12 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.1, 140.2, 140.0, 138.7, 135.6, 133.3, 130.3, 128.7, 128.5, 126.1, 122.9, 116.8, 60.6, 43.6, 42.2, 36.0, 31.8, 29.4, 29.2, 28.4, 26.9, 24.7, 22.7, 21.2, 19.1, 14.1; HRMS (ESI-TOF) Calcd for C27H38NO ([MH]) 392.2948. Found 392.2949. 2h2, 1-(3,5-dimethyl-3-(3-methylphenethyl)indolin-1yl)octan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 51% yield (50 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 6.8 Hz, 3H), 1.30-1.39 (m, 11H), 1.68-1.75 (m, 2H), 1.861.99 (m, 2H), 2.30-2.43 (m, 9H), 2.49-2.56 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 6.90-7.03 (m, 5H), 7.14 (dd, J 7.8, 7.8 Hz, 1H), 8.11 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.1, 141.8, 140.2, 138.7, 138.0, 133.3, 129.1, 128.4, 128.3, 126.7, 125.2, 122.9, 116.7, 60.6, 43.6, 43.4, 36.0, 31.8, 31.0, 29.4, 29.2, 27.1, 24.7, 22.7, 21.4, 21.2, 14.1; HRMS (ESI-TOF) Calcd for C27H38NO ([MH]) 392.2948. Found 392.2946. 2h3, 1-(3,5-dimethyl-3-(4-methylphenethyl)indolin-1yl)octan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 45% yield (44 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 6.8 Hz, 3H), 1.30-1.39 (m, 11H), 1.68-1.75 (m, 2H), 1.861.94 (m, 2H), 2.30-2.42 (m, 9H), 2.48-2.56 (m, 1H), 3.67 (d, J 10.3 Hz, 1H), 3.88 (d, J 10.3 Hz, 1H), 6.92 (s, 1H), 6.987.07 (m, 5H), 8.11 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.1, 140.2, 138.77, 138.75, 135.4, 133.3, 129.1, 128.4, 128.1, 122.9, 116.7, 60.6, 43.6, 43.5, 36.0,
7 ACS Paragon Plus Environment
The Journal of Organic Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
31.8, 30.6, 29.4, 29.2, 27.2, 24.7, 22.7, 21.2, 21.0, 14.1; HRMS (ESI-TOF) Calcd for C27H38NO ([MH]) 392.2948. Found 392.2940. 2i1, 1-(3-(2-chlorophenethyl)-3,5-dimethylindolin-1yl)propan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 81% yield (69 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.24 (t, J 7.4 Hz, 3H), 1.41 (s, 3H), 1.82-1.95 (m, 2H), 2.33 (s, 3H), 2.41-2.53 (m, 3H), 2.65-2.73 (m, 1H), 3.72 (d, J 10.4 Hz, 1H), 4.01 (d, J 10.3 Hz, 1H), 6.95 (s, 1H), 7.03 (d, J 8.4 Hz, 1H), 7.08-7.17 (m, 3H), 7.31 (dd, J 2.0, 7.0 Hz, 1H), 8.12 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.7, 140.2, 139.4, 138.5, 133.7, 133.3, 130.3, 129.5, 128.5, 127.5, 126.9, 122.9, 116.7, 60.2, 43.7, 41.7, 29.22, 29.16, 27.0, 21.2, 8.8; HRMS (ESI-TOF) Calcd for C21H25ClNO ([MH]) 342.1619. Found 342.1622. 2i2, 1-(3-(3-chlorophenethyl)-3,5-dimethylindolin-1yl)propan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 66% yield (56 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.23 (t, J 7.4 Hz, 3H), 1.40 (s, 3H), 1.85-1.98 (m, 2H), 2.33 (s, 3H), 2.35-2.42 (m, 3H), 2.49-2.56 (m, 1H), 3.70 (d, J 10.4 Hz, 1H), 3.88 (d, J 10.4 Hz, 1H), 6.91 (s, 1H), 6.96 (d, J 6.9 Hz, 1H), 7.04 (d, J 8.4 Hz, 1H), 7.09 (s, 1H), 7.13-7.19 (m, 2H), 8.12 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.6, 143.9, 140.2, 138.2, 134.2, 133.3, 129.7, 128.6, 128.3, 126.5, 126.1, 122.9, 116.7, 60.4, 43.6, 43.2, 30.8, 29.1, 27.2, 21.2, 8.8; HRMS (ESI-TOF) Calcd for C21H25ClNO ([MH]) 342.1619. Found 342.1634. 2i3, 1-(3-(4-chlorophenethyl)-3,5-dimethylindolin-1yl)propan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 64% yield (55 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.22 (t, J 7.4 Hz, 3H), 1.40 (s, 3H), 1.83-1.97 (m, 2H), 2.33 (s, 3H), 2.35-2.43 (m, 3H), 2.45-2.56 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.86 (d, J 10.3 Hz, 1H), 6.91 (s, 1H), 7.01-7.04 (m, 3H), 7.21 (d, J 8.3 Hz, 2H), 8.12 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.6, 140.3, 138.3, 133.3, 131.7, 129.6, 128.6, 128.5, 122.9, 116.7, 60.4, 43.6, 43.4, 30.5, 29.1, 27.2, 21.2, 8.7; HRMS (ESI-TOF) Calcd for C21H25ClNO ([MH]) 342.1619. Found 342.1618. 2i4, 1-(3-(4-fluorophenethyl)-3,5-dimethylindolin-1yl)propan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 50% yield (41 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.22 (t, J 7.4 Hz, 3H), 1.40 (s, 3H), 1.84-1.97 (m, 2H), 2.33-2.41 (m, 6H), 2.48-2.56 (m, 1H), 3.68 (d, J 10.3 Hz, 1H), 3.87 (d, J 10.3 Hz, 1H), 6.91-6.95 (m, 3H), 7.02-7.06 (m, 3H), 8.12 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.6, 162.3 (d, 1J(C–F) 242.2 Hz), 140.2, 138.4, 137.4 (d, 4J(C–F) 3.0 Hz), 133.3, 129.6 (d, 3J(C–F) 7.7 Hz), 128.5, 122.9, 116.7, 115.1 (d, 2J(C–F) 21.0 Hz), 60.4, 43.6, 30.3, 29.1, 27.2, 21.2, 8.8; 19F NMR (376 MHz, CDCl3) –117.54 (m, 1F); HRMS (ESI-TOF) Calcd for C21H25FNO ([MH]) 326.1915. Found 326.1919. 2j, 1-(3-(3,5-dimethylphenethyl)-3,5-dimethylindolin-1yl)octan-1-one, isolated by flash column chromatography
Page 8 of 15
(petroleum ether/ethyl acetate 30:1) in 60% yield (61 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 0.88 (t, J 6.8 Hz, 3H), 1.26-1.39 (m, 11H), 1.68-1.76 (m, 2H), 1.851.97 (m, 2H), 2.17-2.42 (m, 12H), 2.45-2.52 (m, 1H), 3.67 (d, J 10.3 Hz, 1H), 3.89 (d, J 10.3 Hz, 1H), 6.72 (s, 2H), 6.80 (s, 1H), 6.92 (s, 1H), 7.02 (d, J 8.4 Hz, 1H), 8.11 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.1, 141.8, 140.2, 138.8, 137.9, 133.2, 128.4, 127.6, 126.1, 122.9, 116.7, 60.6, 43.6, 43.5, 36.0, 31.8, 30.9, 29.4, 29.2, 27.1, 24.7, 22.7, 21.24, 21.17, 14.1; HRMS (ESI-TOF) Calcd for C28H40NO ([MH]) 406.3104. Found 406.3108. 2k, 1-(3,5-dimethyl-3-(2(perfluorophenyl)ethyl)indolin-1-yl)propan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 76% yield (76 mg), colorless crystal: mp 94-95 C. 1H NMR (400 MHz, CDCl3) 1.25 (t, J 7.4 Hz, 3H), 1.41 (s, 3H), 1.80-1.92 (m, 2H), 2.33 (s, 3H), 2.40-2.52 (m, 3H), 2.59-2.69 (m, 1H), 3.76 (d, J 10.4 Hz, 1H), 3.98 (d, J 10.5 Hz, 1H), 6.92 (s, 1H), 7.04 (d, J 8.3 Hz, 1H), 8.11 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.6, 140.2, 137.4, 133.5, 128.8, 122.7, 116.7, 59.9, 43.6, 40.7, 29.2, 27.2, 21.1, 18.0, 8.8; 19F NMR (376 MHz, CDCl3) –144.93 (m, 2F), –157.53 (m, 1F), –162.59 (m, 2F); HRMS (ESI-TOF) Calcd for C21H21F5NO ([MH]) 398.1538. Found 398.1540. 3, 2-(1-acetyl-3-methylindolin-3-yl)-1-phenylethan-1one, isolated by flash column chromatography (petroleum ether/ethyl acetate 15:1) in 17% yield (12 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.50 (s, 3H), 2.23 (s, 3H), 3.24 (d, J 17.3 Hz, 1H), 3.53 (d, J 17.3 Hz, 1H), 4.06 (d, J 11.0 Hz, 1H), 4.20 (d, J 11.0 Hz, 1H), 7.06 (dd, J 6.8, 6.8 Hz, 1H), 7.18-7.25 (m, 2H), 7.46 (dd, J 7.5, 7.5 Hz, 2H), 7.57 (dd, J 7.4, 7.4 Hz, 1H), 7.91 (d, J 7.3 Hz, 2H), 8.21 (d, J 8.0 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 198.3, 168.9, 141.6, 139.2, 137.2, 133.4, 128.7, 128.3, 128.0, 123.8, 122.1, 117.2, 61.3, 48.1, 42.2, 26.4, 24.3; HRMS (ESI-TOF) Calcd for C19H20NO2 ([MH]) 294.1489. Found 294.1490. 4, 1-acetyl-3-ethyl-3-methylindoline-5-carbonitrile, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 12% yield (7 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.83 (t, J 7.5 Hz, 3H), 1.36 (s, 3H), 1.68 (q, J 7.5 Hz, 2H), 2.26 (s, 3H), 3.74 (d, J 10.3 Hz, 1H), 3.92 (d, J 10.3 Hz, 1H), 7.34 (s, 1H), 7.52 (dd, J 1.7, 8.4 Hz, 1H), 8.27 (d, J 8.4 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 169.4, 145.9, 140.1, 132.9, 126.3, 119.4, 117.1, 106.6, 61.0, 43.9, 34.0, 26.6, 24.3, 8.8; HRMS (ESI-TOF) Calcd for C14H17N2O ([MH]) 229.1335. Found 229.1346 5a, 2,4-dimethyl-4-phenethyl-3,4-dihydroisoquinolin1(2H)-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 50% yield (35 mg), yellow oil. 1H NMR (400 MHz, CDCl3) 1.41 (s, 3H), 1.86-2.02 (m, 2H), 2.37-2.44 (m, 1H), 2.55-2.62 (m, 1H), 3.14 (s, 3H), 3.30 (d, J 12.5 Hz, 1H), 3.51 (d, J 12.6 Hz, 1H), 7.08 (d, J 7.3 Hz, 2H), 7.16 (dd, J 7.4, 7.4 Hz, 1H), 7.23 (dd, J 7.5, 7.5 Hz, 2H), 7.29 (d, J 7.8 Hz, 1H), 7.35 (dd, J 7.5, 7.6 Hz, 1H), 7.48 (dd, J 7.5, 7.5 Hz, 1H), 8.13
8 ACS Paragon Plus Environment
Page 9 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
(d, J 7.7 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 164.5, 145.1, 141.8, 131.7, 128.7, 128.5, 128.3, 128.2, 126.9, 126.0, 124.3, 58.6, 41.6, 37.3, 35.3, 31.0, 23.2; HRMS (ESI-TOF) Calcd for C19H22NO ([MH]) 280.1696. Found 280.1692. 5b, 2,4-dimethyl-4-(2-methylphenethyl)-3,4dihydroisoquinolin-1(2H)-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 38% yield (28 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.44 (s, 3H), 1.77-1.92 (m, 2H), 2.13 (s, 3H), 2.34-2.42 (m, 1H), 2.53-2.61 (m, 1H), 3.16 (s, 3H), 3.31 (d, J 12.5 Hz, 1H), 3.55 (d, J 12.5 Hz, 1H), 7.00-7.19 (m, 4H), 7.31 (d, J 7.7 Hz, 1H), 7.36 (dd, J 6.8, 7.5 Hz, 1H), 7.48 (ddd, J 1.2, 7.6, 7.4 Hz, 1H), 8.14 (d, J 6.8 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 164.5, 145.1, 139.9, 135.6, 131.7, 130.3, 128.8, 128.7, 128.3, 126.9, 126.2, 126.1, 124.3, 58.7, 40.5, 37.3, 35.4, 28.2, 22.9, 19.0; HRMS (ESI-TOF) Calcd for C20H24NO ([MH]) 294.1852. Found 294.1851. 6a, 1-(3-phenethylindolin-1-yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 50% yield (33 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.86-1.95 (m, 1H), 2.13-2.18 (m, 1H), 2.20 (s, 3H), 2.72 (t, J 7.4 Hz, 2H), 3.40-3.47 (m, 1H), 3.68 (dd, J 6.0, 10.3 Hz, 1H), 4.14 (dd, J 9.9, 9.9 Hz, 1H), 7.03 (dd, J 7.4, 7.4 Hz, 1H), 7.17-7.23 (m, 5H), 7.31 (dd, J 7.1, 7.6 Hz, 2H), 8.20 (d, J 8.0 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.7, 142.7, 141.3, 134.7, 128.6, 128.4, 128.0, 126.2, 123.8, 123.7, 117.0, 55.0, 39.7, 37.0, 33.2, 24.3; HRMS (ESI-TOF) Calcd for C18H20NO ([MH]) 266.1539. Found 266.1538. 6b, 1-(5-methyl-3-phenethylindolin-1-yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 40:1) in 57% yield (40 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.84-1.93 (m, 1H), 2.12-2.20 (m, 4H), 2.31 (s, 3H), 2.69-2.74 (m, 2H), 3.363.43 (m, 1H), 3.66 (dd, J 6.0, 10.4 Hz, 1H), 4.12 (dd, J 9.9, 9.9 Hz, 1H), 6.98-7.02 (m, 2H), 7.19-7.23 (m, 3H), 7.29-7.32 (m, 2H), 8.07 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.3, 141.4, 140.4, 134.9, 133.3, 128.6, 128.39, 128.35, 126.2, 124.4, 116.7, 55.1, 39.7, 37.0, 33.3, 24.1, 21.1; HRMS (ESI-TOF) Calcd for C19H22NO ([MH]) 280.1696. Found 280.1699. 6c, 1-(5-chloro-3-phenethylindolin-1-yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 30:1) in 62% yield (46 mg), white solid: mp 88-89 C. 1H NMR (400 MHz, CDCl3) 1.85-1.95 (m, 1H), 2.10-2.23 (m, 4H), 2.69-2.74 (m, 2H), 3.37-3.44 (m, 1H), 3.69 (dd, J 6.1, 10.4 Hz, 1H), 4.14 (dd, J 9.9, 9.9 Hz, 1H), 7.13-7.24 (m, 5H), 7.29-7.33 (m, 2H), 8.13 (d, J 8.6 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 168.6, 141.4, 140.9, 136.7, 128.6, 128.5, 128.3, 127.9, 126.3, 124.0, 118.0, 55.1, 39.5, 36.8, 33.1, 24.1; HRMS (ESI-TOF) Calcd for C18H19ClNO ([MH]) 300.1150. Found 300.1161. 6d, 1-(5-methyl-3-phenethylindolin-1-yl)propan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 40:1) in 60% yield (44 mg), white solid: mp 83-84 C. 1H NMR (400 MHz, CDCl3) 1.22 (t, J 7.4 Hz, 3H), 1.83-1.92 (m, 1H), 2.11-2.20 (m, 1H), 2.31 (s,
3H), 2.40 (q, J 7.4 Hz, 2H), 2.69-2.73 (m, 2H), 3.35-3.42 (m, 1H), 3.66 (dd, J 5.9, 10.3 Hz, 1H), 4.11 (dd, J 9.9, 9.9 Hz, 1H), 6.98-7.02 (m, 2H), 7.19-7.22 (m, 3H), 7.28-7.32 (m, 2H), 8.11 (d, J 8.2 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.6, 141.4, 140.7, 134.7, 133.1, 128.5, 128.40, 128.35, 126.1, 124.4, 116.6, 54.1, 39.7, 37.0, 33.3, 29.1, 21.1, 8.8; HRMS (ESI-TOF) Calcd for C20H24NO ([MH]) 294.1852. Found 294.1850. 6e, 1-(5-methyl-3-phenethylindolin-1-yl)octan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 55:1) in 46% yield (42 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 0.89 (t, J 6.8 Hz, 3H), 1.29-1.40 (m, 8H), 1.68-1.75 (m, 2H), 1.83-1.92 (m, 1H), 2.11-2.19 (m, 1H), 2.30 (s, 3H), 2.36 (t, J 7.6 Hz, 2H), 2.71 (t, J 6.9 Hz, 2H), 3.34-3.41 (m, 1H), 3.66 (dd, J 6.0, 10.3 Hz, 1H), 4.11 (dd, J 9.8, 9.9 Hz, 1H), 6.97-7.01 (m, 2H), 7.19-7.22 (m, 3H), 7.28-7.32 (m, 2H), 8.10 (d, J 8.1 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl3) 171.1, 141.4, 140.6, 134.8, 133.1, 128.5, 128.38, 128.36, 126.1, 124.4, 116.7, 54.3, 39.7, 37.0, 36.0, 33.3, 31.8, 29.4, 29.2, 24.7, 22.7, 21.1, 14.1; HRMS (ESI-TOF) Calcd for C25H34fNO ([MH]) 364.2635. Found 364.2628. 7, methyl 1-acetyl-5-chloro-3-phenethylindoline-3carboxylate, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 53% yield (49 mg), white solid: mp 154-155 C. 1H NMR (400 MHz, CDCl3) 2.11-2.18 (m, 1H), 2.21 (s, 3H), 2.45-2.58 (m, 3H), 3.76 (s, 3H), 3.84 (d, J 10.8 Hz, 1H), 4.71 (d, J 10.8 Hz, 1H), 7.13-7.15 (m, 2H), 7.18-7.25 (m, 2H), 7.29 (dd, J 7.6, 7.6 Hz, 2H), 7.38 (d, J 2.1 Hz, 1H), 8.15 (d, J 8.7 Hz, 1H); 13C{1H} NMR (100 MHz, CDCl ) 172.5, 168.5, 140.9, 3 140.2, 133.7, 129.3, 128.8, 128.6, 128.3, 126.5, 124.6, 118.0, 56.3, 54.9, 53.1, 40.5, 31.3, 24.1; HRMS (ESI-TOF) Calcd for C20H21ClNO3 ([MH]) 358.1204. Found 358.1207. 8, 1-(3-phenethyl-1H-indol-1-yl)ethan-1-one, isolated by flash column chromatography (petroleum ether/ethyl acetate 24:1) in 67% yield (44 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 2.54 (s, 3H), 3.01 (s, 4H), 7.07 (brs, 1H, unexchangeable), 7.20-7.24 (m, 3H), 7.26-7.37 (m, 4H), 7.52 (d, J 7.8 Hz, 1H), 8.43 (brd, J 6.5 Hz, 1H, unexchangeable); 13C{1H} NMR (100 MHz, CDCl3) 168.4, 141.6, 136.0, 130.6, 128.5, 126.2, 125.3, 123.4, 122.4, 122.0, 118.9, 116.7, 35.5, 27.0, 24.0; HRMS (ESI-TOF) Calcd for C18H18NO ([MH]) 264.1383. Found 264.1382. 9, 4-benzyl-2,6-di-tert-butyl-4-methylcyclohexa-2,5dien-1-one, isolated by flash column chromatography (pure petroleum ether) in 71% yield (55 mg), yellow solid: mp 83-84 C. 1H NMR (400 MHz, CDCl3) 1.14 (s, 18H), 1.27 (s, 3H), 2.82 (s, 2H), 6.47 (s, 2H), 6.94-6.97 (m, 2H), 7.12-7.20 (m, 3H); 13C{1H} NMR (100 MHz, CDCl3) 186.1, 146.1, 145.9, 136.7, 130.1, 127.5, 126.6, 48.1, 40.9, 34.6, 29.3, 26.2; HRMS (ESI-TOF) Calcd for C22H31O ([MH]) 311.2369. Found 311.2371. Synthesis of Allyl Amines 1. Substrates 1 were prepared from anilides and allyl bromides according to the literature procedure, and spectral data of known compounds match those described.32a-c Spectral data of
9 ACS Paragon Plus Environment
The Journal of Organic Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
new compounds or known compounds prepared by the new method are shown below. 1a1-d5, N-(2-methylallyl)-N-(phenyl-d5)acetamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 15:1) in 92% yield (2681 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.76 (s, 3H), 1.90 (s, 3H), 4.29 (s, 2H), 4.70 (s, 1H), 4.81 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) 170.3, 143.0, 140.7, 129.0 (t, J(C– D) 24.1 Hz), 127.3 (t, J(C–D) 24.5 Hz), 127.2 (t, J(C–D) 23.7 Hz), 113.1, 55.0, 22.7, 20.3; HRMS (ESI-TOF) Calcd for C12H11D5NO ([MH]) 195.1540. Found 195.1542. 1a6, N-(4-methoxyphenyl)-N-(2-methylallyl)acetamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 88% yield (2895 mg), white solid: mp 60-61 C. 1H NMR (400 MHz, CDCl3) 1.75 (s, 3H), 1.88 (s, 3H), 3.82 (s, 3H), 4.24 (s, 2H), 4.69 (s, 1H), 4.81 (s, 1H), 6.89 (ddd, J 3.4, 2.2, 8.9 Hz, 2H), 7.07 (ddd, J 3.4, 2.2, 8.9 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 170.8, 158.8, 140.9, 136.0, 128.9, 114.6, 113.2, 55.4, 55.1, 22.7, 20.3; HRMS (ESI-TOF) Calcd for C13H18NO2 ([MH]) 220.1332. Found 220.1333. 1a7, N-(2-methylallyl)-N-(4(trifluoromethyl)phenyl)acetamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 90% yield (3473 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.67 (s, 3H), 1.86 (s, 3H), 4.22 (s, 2H), 4.63 (s, 1H), 4.76 (s, 1H), 7.25 (d, J 8.2 Hz, 2H), 7.58 (d, J 8.2 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 169.8, 146.2, 140.3, 129.5, 128.1, 126.6, 123.7 (q, 1J(C–F) 270.5 Hz), 113.4, 54.8, 22.7, 20.1; 19F NMR (376 MHz, CDCl3) – 62.64 (s, 3F); HRMS (ESI-TOF) Calcd for C13H15F3NO ([MH]) 258.1100. Found 258.1106. N-(4-Cyanophenyl)-N-(2-methylallyl)acetamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 20:1) in 76% yield (2443 mg), white solid: mp 122-123 C. 1H NMR (400 MHz, CDCl3) 1.75 (s, 3H), 2.01 (s, 3H), 4.29 (s, 2H), 4.73 (s, 1H), 4.88 (s, 1H), 7.33 (d, J 8.2 Hz, 2H), 7.69 (d, J 8.2 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 169.8, 147.1, 140.2, 133.4, 128.1, 118.1, 113.4, 55.2, 22.8, 20.2; HRMS (ESI-TOF) Calcd for C13H15N2O ([MH]) 215.1179. Found 215.1171. 1b, N-(2-methylallyl)-N-(pyridin-4-yl)acetamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 1:1) in 44% yield (1256 mg), brown oil. 1H NMR (400 MHz, CDCl3) 1.75 (s, 3H), 2.09 (s, 3H), 4.29 (s, 2H), 4.77 (s, 1H), 4.90 (s, 1H), 7.18 (d, J 5.5 Hz, 2H), 8.62 (d, J 4.8 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 169.9, 151.0, 150.5, 140.1, 121.2, 112.9, 54.8, 22.9, 20.2; HRMS (ESI-TOF) Calcd for C11H15N2O ([MH]) 191.1179. Found 191.1180. 1d5, N-(2-methylallyl)-N-(p-tolyl)pivalamide, prepared from 4-methyl-N-(2-methylallyl)aniline and pivaloyl chloride and isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 77% yield (2834 mg), yellow oil. 1H NMR (400 MHz, CDCl3) 1.04 (s, 9H), 1.74 (s, 3H), 2.36 (s, 3H), 4.18 (s, 2H), 4.67 (s, 1H), 4.80 (s, 1H), 7.06 (ddd, J 1.6, 1.6, 8.2 Hz, 2H), 7.14 (d, J 8.0 Hz,
Page 10 of 15
2H); 13C{1H} NMR (100 MHz, CDCl3) 177.7, 141.2, 137.7, 129.5, 129.2, 112.3, 58.6, 41.1, 29.6, 21.1, 20.4; HRMS (ESITOF) Calcd for C16H24NO ([MH]) 246.1852. Found 246.1856. 1e, tert-butyl (2-methylallyl)(p-tolyl)carbamate, isolated by flash column chromatography (petroleum ether/ethyl acetate 300:1) in 81% yield (3176 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.44 (s, 9H), 1.74 (d, J 0.5 Hz, 3H), 2.31 (s, 3H), 4.14 (s, 2H), 4.79-4.81 (m, 1H), 4.83-4.84 (m, 1H), 7.10 (s, 4H); 13C{1H} NMR (100 MHz, CDCl3) 154.8, 141.8, 140.3, 135.2, 129.1, 125.9, 111.3, 80.2, 55.9, 28.3, 21.0, 20.1; HRMS (ESI-TOF) Calcd for C16H24NO2 ([MH]) 262.1802. Found 262.1809. 1f, N-(4-chlorophenyl)-N-(2methylallyl)ethanesulfonamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 24:1) in 87% yield (3573 mg), yellow oil. 1H NMR (400 MHz, CDCl3) 1.38 (t, J 7.4 Hz, 3H), 1.74 (s, 3H), 3.04 (q, J 7.4 Hz, 2H), 4.27 (s, 2H), 4.78 (s, 1H), 4.81 (s, 1H), 7.27-7.35 (m, 4H); 13C{1H} NMR (100 MHz, CDCl3) 139.8, 137.6, 133.4, 129.42, 129.38, 115.4, 57.2, 45.3, 19.8, 8.0; HRMS (ESI-TOF) Calcd for C12H17ClNO2S ([MH]) 274.0663. Found 274.0663. 1g, N-(3,5-dichlorophenyl)-N-(2-methylallyl)octanamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 80:1) in 91% yield (4672 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 0.86 (t, J 7.0 Hz, 3H), 1.23-1.27 (m, 8H), 1.60 (s, 2H), 1.74 (s, 3H), 2.13 (s, 2H), 4.22 (s, 2H), 4.71 (s, 1H), 4.88 (s, 1H), 7.08 (s, 2H), 7.33 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) 172.6, 144.8, 140.3, 135.4, 128.0, 126.7, 113.5, 55.2, 34.4, 31.6, 29.2, 29.0, 25.4, 22.6, 20.3, 14.1; HRMS (ESI-TOF) Calcd for C18H26Cl2NO ([MH]) 342.1386. Found 342.1385. N-(But-2-en-1-yl)-N-(4-chlorophenyl)acetamide, 4:17 mixture of Z/E isomers, isolated by flash column chromatography (petroleum ether/ethyl acetate 12:1) in 82% yield (2752 mg), colorless oil. 1H NMR (400 MHz, CDCl3) 1.46 (d, J 6.7 Hz, 3H minor), 1.60-1.68 (m, 3H major), 1.84 (s, 3H major and 3H minor), 4.16-4.23 (m, 2H major), 4.33 (d, J 7.0 Hz, 2H minor), 5.42-5.63 (stack, 2H major and 2H minor), 7.08-7.13 (stack, 2H major and 2H minor), 7.37 (d, J 8.5 Hz, 2H major and 2H minor); 13C{1H} NMR (100 MHz, CDCl3) 169.8 (minor), 169.7 (major), 141.54 (major), 141.50 (minor), 133.7 (minor), 133.6 (major), 129.8 (minor), 129.7 (major), 129.6 (major), 129.5 (minor), 128.2 (minor), 125.5 (major), 124.8 (minor), 51.2 (major), 45.4 (minor), 22.7 (major), 22.6 (minor), 17.7 (major), 12.7 (minor); HRMS (ESI-TOF) Calcd for C12H15ClNO ([MH]) 224.0837. Found 224.0831. 3-Chloro-N-(2-methylallyl)-N-(p-tolyl)benzamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 86% yield (3867 mg), pale yellow solid: mp 43-44 C. 1H NMR (400 MHz, CDCl3) 1.81 (s, 3H), 2.27 (s, 3H), 4.46 (s, 2H), 4.87 (s, 1H), 4.90 (s, 1H), 6.90 (d, J 8.1 Hz, 2H), 7.01 (d, J 8.1 Hz, 2H), 7.057.13 (m, 2H), 7.21 (ddd, J 1.6, 1.6, 7.6 Hz, 1H), 7.37 (s, 1H); 13C{1H} NMR (100 MHz, CDCl ) 168.9, 140.8, 140.6, 3
10 ACS Paragon Plus Environment
Page 11 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
138.0, 136.7, 133.9, 129.7, 129.6, 129.0, 128.9, 126.9, 126.7, 112.8, 55.8, 21.0, 20.5; HRMS (ESI-TOF) Calcd for C18H19ClNO ([MH]) 300.1150. Found 300.1154. N-Methyl-N-(2-methylallyl)benzamide, 2:3 mixture of rotamers, isolated by flash column chromatography (petroleum ether/ethyl acetate 40:1) in 88% yield (2498 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.60 (s, 3H major), 1.78 (s, 3H minor), 2.88 (s, 3H minor), 3.04 (s, 3H major), 3.77 (s, 2H major), 4.13 (s, 2H minor), 4.89 (s, 1H minor), 4.92 (s, 1H major), 4.97 (s, 1H minor), 4.98 (s, 1H major), 7.36-7.44 (stack, 5H major and 5H minor); 13C{1H} NMR (100 MHz, CDCl ) 172.3 (major), 171.4 3 (minor), 140.5 (major), 140.2 (minor), 136.4 (minor), 136.2 (major), 129.6 (major), 129.5 (minor), 128.3 (major and minor), 126.8 (minor), 126.6 (major), 112.5 (minor), 112.2 (major), 57.3 (major), 52.8 (minor), 36.8 (minor), 33.2 (major), 19.90 (minor), 19.86 (major); HRMS (ESITOF) Calcd for C12H16NO ([MH]) 190.1226. Found 190.1225. N-Allyl-N-(p-tolyl)acetamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 40:1) in 93% yield (2640 mg), yellow oil. 1H NMR (400 MHz, CDCl3) 1.85 (s, 3H), 2.37 (s, 3H), 4.27 (d, J 6.3 Hz, 2H), 5.045.11 (m, 2H), 5.80-5.90 (m, 1H), 7.03 (d, J 8.2 Hz, 2H), 7.19 (d, J 8.0 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 170.3, 140.4, 137.8, 133.3, 130.2, 127.8, 117.7, 52.0, 22.6, 21.1; HRMS (ESI-TOF) Calcd for C12H16NO ([MH]) 190.1226. Found 190.1223. N-Allyl-N-(4-chlorophenyl)acetamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 90% yield (2831 mg), yellow solid: mp 45-46 C. 1H NMR (400 MHz, CDCl ) 1.86 (s, 3H), 4.27 (ddd, J 3 1.2, 1.2, 6.2 Hz, 2H), 5.04-5.13 (m, 2H), 5.79-5.89 (m, 1H), 7.10 (d, J 8.5 Hz, 2H), 7.38 (d, J 8.6 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 169.9, 141.5, 133.8, 132.9, 129.8, 129.5, 118.2, 52.0, 22.7; HRMS (ESI-TOF) Calcd for C11H13ClNO ([MH]) 210.0680. Found 210.0682. N-Allyl-N-(p-tolyl)propionamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 89% yield (2714 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.04 (t, J 7.5 Hz, 3H), 2.06 (q, J 7.4 Hz, 2H), 2.37 (s, 3H), 4.27 (d, J 6.3 Hz, 2H), 5.03-5.10 (m, 2H), 5.81-5.91 (m, 1H), 7.03 (d, J 8.2 Hz, 2H), 7.19 (d, J 8.0 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 173.7, 140.0, 137.7, 133.4, 130.1, 128.0, 117.6, 52.2, 27.7, 21.1, 9.6; HRMS (ESI-TOF) Calcd for C13H18NO ([MH]) 204.1383. Found 204.1377. N-Allyl-N-(p-tolyl)octanamide, isolated by flash column chromatography (petroleum ether/ethyl acetate 60:1) in 85% yield (3486 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 0.84 (t, J 6.8 Hz, 3H), 1.18-1.26 (m, 8H), 1.521.59 (m, 2H), 2.04 (t, J 7.7 Hz, 2H), 2.37 (s, 3H), 4.26 (ddd, J 1.1, 1.1, 6.3 Hz, 2H), 5.03-5.10 (m, 2H), 5.80-5.90 (m, 1H), 7.01 (d, J 8.1 Hz, 2H), 7.19 (d, J 8.0 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 173.0, 140.1, 137.7, 133.5, 130.1, 128.1, 117.6, 52.2, 34.3, 31.6, 29.2, 29.0, 25.5, 22.6,
21.1, 14.1; HRMS (ESI-TOF) Calcd for C18H28NO ([MH]) 274.2165. Found 274.2168. N-Phenyl-N-(2-phenylallyl)acetamide,43 isolated by flash column chromatography (petroleum ether/ethyl acetate 32:1) in 77% yield (2903 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.79 (s, 3H), 4.87 (s, 2H), 5.00 (s, 1H), 5.33 (s, 1H), 6.90-6.92 (s, 2H), 7.25-7.35 (s, 6H), 7.40-7.42 (m, 2H); 13C{1H} NMR (100 MHz, CDCl3) 170.3, 143.8, 142.2, 138.5, 129.3, 128.4, 128.2, 127.9, 127.8, 126.4, 115.9, 51.9, 22.8; HRMS (ESI-TOF) Calcd for C17H18NO ([MH]) 252.1383. Found 252.1392. Methyl 2-((N-(4chlorophenyl)acetamido)methyl)acrylate, prepared from methyl 2-(((4-chlorophenyl)amino)methyl)acrylate and acetyl chloride and isolated by flash column chromatography (petroleum ether/ethyl acetate 16:1) in 90% yield (3614 mg), white solid: mp 63-64 C. 1H NMR (400 MHz, CDCl3) 1.91 (s, 3H), 3.70 (s, 3H), 4.57 (s, 2H), 5.74 (d, J 1.0 Hz, 1H), 6.32 (s, 1H), 7.10 (d, J 8.5 Hz, 2H), 7.37 (d, J 8.5 Hz, 2H); 13C{1H} NMR (100 MHz, CDCl3) 170.3, 166.3, 141.6, 135.4, 133.9, 129.9, 129.2, 127.3, 52.0, 50.0, 22.7; HRMS (ESI-TOF) Calcd for C13H15ClNO3 ([MH]) 268.0735. Found 268.0741. N-(2-Bromoallyl)-N-phenylacetamide,44 isolated by flash column chromatography (petroleum ether/ethyl acetate 16:1) in 42% yield (1601 mg), pale yellow oil. 1H NMR (400 MHz, CDCl3) 1.91 (s, 3H), 4.60 (s, 2H), 5.51 (s, 1H), 5.65 (s, 1H), 7.24-7.27 (m, 2H), 7.34-7.44 (m, 3H); 13C{1H} NMR (100 MHz, CDCl3) 170.5, 142.2, 129.7, 128.6, 128.2, 128.0, 119.5, 56.3, 22.7; HRMS (ESI-TOF) Calcd for C11H13BrNO ([MH]) 254.0175. Found 254.0177.
ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website. 1H, 19F, 13C and DEPT NMR Spectra (PDF)
AUTHOR INFORMATION Corresponding Author
[email protected] Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT We gratefully acknowledge the financial support from the National Natural Science Foundation of China (21702083), the Yunnan Ten Thousand Talent Program for Young Top-Notch Talents, and the Program for Innovative Research Team (in Science and Technology) in Universities of Yunnan Province.
REFERENCES (1) (a) Chen, B.; Wu, L.; Tung, C. Photocatalytic Activation of Less Reactive Bonds and Their Functionalization via HydrogenEvolution Cross-Couplings. Acc. Chem. Res. 2018, 51, 2512–2523. (b) Kӓrkӓs, M. D. Electrochemical strategies for C–H functionalization and C–N bond formation. Chem. Soc. Rev. 2018,
11 ACS Paragon Plus Environment
The Journal of Organic Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
47, 5786–5865. (c) Yi, H.; Zhang, G.; Wang, H.; Huang, Z.; Wang, J.; Singh, A. K.; Lei, A. Recent Advances in Radical C–H Activation/Radical Cross-Coupling. Chem. Rev. 2017, 117, 9016– 9085. (d) Labinger, J. A. Platinum-catalyzed C–H functionalization. Chem. Rev. 2017, 117, 8483–8496. (e) Pototschnig, G.; Maulide, N.; Schnürch, M. Direct Functionalization of C−H Bonds by Iron, Nickel, and Cobalt Catalysis. Chem. Eur. J. 2017, 23, 9206–9232. (2) White, M. C.; Zhao, J. Aliphatic C–H oxidations for late-stage functionalization. J. Am. Chem. Soc. 2018, 140, 13988−14009. (3) (a) Li, S.; Wang, B.; Dong, G.; Li, C.; Liu, H. Cobalt-catalyzed C(sp3)–H/C(sp2)–H oxidative coupling between alkanes and benzamides. RSC Adv. 2018, 8, 13454−13458. (b) Li, Q.; Hu, W.; Hu, R.; Lu, H.; Li, G. Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reaction between Unactivated C(sp2)–H and C(sp3)–H Bonds. Org. Lett. 2017, 19, 4676−4679. (c) Li, B.; Fang, S.; Huang, D.; Shi, B. Ru-Catalyzed Meta-C–H Benzylation of Arenes with Toluene Derivatives. Org. Lett. 2017, 19, 3950−3953. (d) Aihara, Y.; Tobisu, M.; Fukumoto, Y.; Chatani, N. Ni(II)-Catalyzed Oxidative Coupling between C(sp2)–H in Benzamides and C(sp3)–H in Toluene Derivatives. J. Am. Chem. Soc. 2014, 136, 15509−15512. (4) Storr, T. E.; Teskey, C. J.; Greaney, M. F. CrossDehydrogenative-Coupling of Alkoxybenzenes with Toluenes: Copper(II) Halide Mediated Tandem Halo/Benzylation of Arenes. Chem. Eur. J. 2016, 22, 18169−18178. (5) (a) Lv, F.; Yu, Y.; Hao, E.; Yu, C.; Wang, H.; Jiao, L.; Boens, N. Copper-catalyzed -benzylation of BODIPYs via radical-triggered oxidative cross-coupling of two C–H bonds. Chem. Commun. 2018, 54, 9059−9062. (b) Hu, L.; Yuan, J.; Fu, J.; Zhang, T.; Gao, L.; Xiao, Y.; Mao, P.; Qu, L. Copper-Catalyzed Direct C-3 Benzylation of Quinoxalin-2(1H)-ones with Methylarenes under Microwave Irradiation. Eur. J. Org. Chem. 2018, 4113−4120. (c) Kianmehr, E.; Gholamhosseyni, M. Visible-Light-Promoted Copper-Catalyzed Regioselective Benzylation of Pyridine N-Oxides versus Thermal Acylation Reaction with Toluene Derivatives. Eur. J. Org. Chem. 2018, 1559−1566. (d) Shi, X.; Zhang, F.; Luo, W.; Yang, L. OxidantTriggered C1-Benzylation of Isoquinoline by Iodine-Catalyzed Cross-Dehydrogenative-Coupling with Methylarenes. Synlett 2017, 28, 494−498. (e) Wan, L.; Qiao, K.; Sun, X. N.; Di, Z. C.; Fang, Z.; Li, Z. J.; Guo, K. Benzylation of heterocyclic N-oxides via direct oxidative cross-dehydrogenative coupling with toluene derivatives. New J. Chem. 2016, 40, 10227−10232. (f) Kianmehr, E.; Faghih, N.; Khan, K. M. Palladium-catalyzed regioselective benzylation–annulation of pyridine N-oxides with toluene derivatives via multiple C–H bond activations: benzylation versus arylation. Org. Lett. 2015, 17, 414−417. (g) Wan, M.; Lou, H.; Liu, L. C1-Benzyl and benzoyl isoquinoline synthesis through direct oxidative cross-dehydrogenative coupling with methyl arenes. Chem. Commun. 2015, 51, 13953−13956. (h) Zhou, S.; Guo, L.; Duan, X. Copper-Catalyzed Regioselective Cross-Dehydrogenative Coupling of Coumarins with Benzylic Csp3-H Bonds. Eur. J. Org. Chem. 2014, 8094–8100. (6) (a) Soni, V.; Khake, S. M.; Punji, B. Nickel-Catalyzed C(sp2)– H/C(sp3)–H Oxidative Coupling of Indoles with Toluene Derivatives. ACS Catal. 2017, 7, 4202−4208. (b) Zhang, H.; Su, F.; Wen, T. Copper-Catalyzed Direct C2-Benzylation of Indoles with Alkylarenes. J. Org. Chem. 2015, 80, 11322−11329. (7) Fan, W.; Shi, D.; Feng, B. TBAI-catalyzed synthesis of ketoamides via sp3 C–H radical/radical cross-coupling and domino aerobic oxidation. Tetrahedron Lett. 2015, 56, 4638–4641. (8) (a) Tanaka, T.; Hashiguchi, K.; Tanaka, T.; Yazaki, R.; Ohshima, T. Chemoselective Catalytic Dehydrogenative CrossCoupling of 2‑Acylimidazoles: Mechanistic Investigations and Synthetic Scope. ACS Catal. 2018, 8, 8430−8440. (b) Tan, M.; Li, K.; Yin, J.; You, J. Manganese/cobalt-catalyzed oxidative C(sp3)– H/C(sp3)–H coupling: a route to -tertiary -arylethylamines. Chem. Commun. 2018, 54, 1221−1224. (c) Yu, H.; Xu, Y.; Dong, R.; Fang, Y. Direct Oxidative Cross-Coupling of Toluene Derivatives
Page 12 of 15
and N-Acyl-2-aminoacetophenones. Adv. Synth. Catal. 2017, 359, 39–43. (d) Curto, J. M.; Kozlowski, M. C. Chemoselective Activation of sp3 vs sp2 C–H Bonds with Pd(II). J. Am. Chem. Soc. 2015, 137, 18−21. (e) Li, Z.; Cao, L.; Li, C. FeCl2-Catalyzed Selective C−C Bond Formation by Oxidative Activation of a Benzylic C−H Bond. Angew. Chem. Int. Ed. 2007, 46, 6505–6507. Angew. Chem. 2007, 119, 6625–6627. (9) The rule of polarity-matching might be inapplicable to radical/radical cross-coupling, and for the homocoupling of methyl arene radical, please see: (a) Wang, Z.; Lv, J.; Yi, R.; Xiao, M.; Feng, J.; Liang, Z.; Wang, A.; Xua, X. Nondirecting Group sp3 C-H Activation for Synthesis of Bibenzyls via Homo-coupling as Catalyzed by Reduced Graphene Oxide Supported PtPd@Pt Porous Nanospheres. Adv. Synth. Catal. 2018, 360, 932–941. (b) Sahoo, S. K. An unprecedented oxidative intermolecular homo coupling reaction between two sp3C–sp3C centers under metalfree condition. Tetrahedron Lett. 2016, 57, 3476–3480. (10) (a) Qin, G.; Chen, X.; Yang, L.; Huang, H. Copper-Catalyzed -Benzylation of Enones via Radical-Triggered Oxidative Coupling of Two C–H Bonds. ACS Catal. 2015, 5, 2882−2885. (b) Gu, H.; Wang, C. Rhenium-catalyzed dehydrogenative olefination of C(sp3)– H bonds with hypervalent iodine(III) reagents. Org. Biomol. Chem. 2015, 13, 5880–5884. (11) Cross-coupling of nucleophilic ketene dithioacetals with methyl arenes was also reported, which might benefit from both the stabilizing effect of the dialkylthio group on radical intermediates and the charge regulation by electron-withdrawing groups: (a) Wen, J.; Zhang, F.; Shi, W.; Lei, A. Metal-Free Direct Alkylation of Ketene Dithioacetals by Oxidative C(sp2)−H/C(sp3)−H Cross-Coupling. Chem. Eur. J. 2017, 23, 8814– 8817. (b) Wang, Q.; Lou, J.; Wu, P.; Wu, K.; Yu, Z. Iron-Mediated Oxidative C−H Alkylation of S,S-Functionalized Internal Olefins via C(sp2)−H/C(sp3)−H Cross-Coupling. Adv. Synth. Catal. 2017, 359, 2981–2998. (12) (a) Ackerman, L. K. G.; Alvarado, J. I. M.; Doyle, A. G. Direct C–C Bond Formation from Alkanes Using Ni-Photoredox Catalysis. J. Am. Chem. Soc. 2018, 140, 14059−14063. (b) Shields, B. J.; Doyle, A. G. Direct C(sp3)–H Cross Coupling Enabled by Catalytic Generation of Chlorine Radicals. J. Am. Chem. Soc. 2016, 138, 12719−12722. (c) Heitz, D. R.; Tellis, J. C.; Molander, G. A. Photochemical nickel-catalyzed C–H arylation: synthetic scope and mechanistic investigations. J. Am. Chem. Soc. 2016, 138, 12715−12718. (d) Huang, R.; Zhang, X.; Pan, J.; Li, J.; Shen, H.; Ling, X.; Xiong, Y. Benzylation of arenes with benzyl halides synergistically promoted by in situ generated superacid boron trifluoride monohydrate and tetrahaloboric acid. Tetrahedron 2015, 71, 1540−1546. (13) Vasilopoulos, A.; Zultanski, S. L.; Stahl, S. S. Feedstocks to Pharmacophores: Cu-Catalyzed Oxidative Arylation of Inexpensive Alkylarenes Enabling Direct Access to Diarylalkanes. J. Am. Chem. Soc. 2017, 139, 7705−7708. (14) (a) Guo, S.; Yuan, Y.; Xiang, J. Copper-catalyzed oxidative alkenylation of C (sp3)–H bonds via benzyl or alkyl radical addition to -nitrostyrenes. New J. Chem. 2015, 39, 3093−3097. (b) Guo, S.; Yuan, Y. Copper-Catalyzed Alkenylation of Alcohols with -Nitrostyrenes via a Radical Addition–Elimination Process. Synlett 2015, 26, 1961–1968. (15) (a) Zhao, Y.; Sun, L.; Zeng, T.; Wang, J.; Peng, Y.; Song, G. Direct olefination of benzaldehydes into 1,3-diarylpropenes via a copper-catalyzed heterodomino Knoevenagel-decarboxylationCsp3-H activation sequence. Org. Biomol. Chem. 2014, 12, 3493– 3498. (b) Yang, H.; Yan, H.; Sun, P.; Zhu, Y.; Lu, L.; Liu, D.; Rong, G.; Mao, J. Iron-catalyzed direct alkenylation of sp3(C–H) bonds via decarboxylation of cinnamic acids under ligand-free conditions. Green Chem. 2013, 15, 976–981. (c) Yang, H.; Sun, P.; Zhu, Y.; Yan, H.; Lu, L.; Qu, X.; Li, T.; Mao, J. Copper-catalyzed decarboxylative
12 ACS Paragon Plus Environment
Page 13 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
C(sp2)–C(sp3) coupling reactions via radical mechanism. Chem. Commun. 2012, 48, 7847–7849. (16) Banerjee, A.; Santra, S. K.; Khatun, N.; Ali, W.; Patel, B. K. Oxidant controlled regioselective mono- and di-functionalization reactions of coumarins. Chem. Commun. 2015, 51, 15422–15425. (17) Paeth, M.; Carson, W.; Luo, J.; Tierney, D.; Cao, Z.; Cheng, M.; Liu, W. Copper Mediated Trifluoromethylation of Benzylic Csp3-H Bonds. Chem. Eur. J. 2018, 24, 11559−11563. (18) Liu, H.; Laurenczy, G.; Yan, N.; Dyson, P. J. Amide bond formation via C(sp3)–H bond functionalization and CO insertion. Chem. Commun. 2014, 50, 341−343. (19) (a) Go, S. Y.; Lee, G. S.; Hong, S. H. Highly Regioselective and E/Z‑Selective Hydroalkylation of Ynone, Ynoate, and Ynamide via Photoredox Mediated Ni/Ir Dual Catalysis. Org. Lett. 2018, 20, 4691−4694. (b) Miao, T.; Xia, D.; Li, Y.; Li, P.; Wang, L. Direct difunctionalization of activated alkynes via domino oxidative benzylation/1,4-aryl migration/decarboxylation reactions under metal-free conditions. Chem. Commun. 2016, 52, 3175−3178. (c) Zhang, Y.; Hu, G.; Ma, D.; Xu, P.; Gao, Y.; Zhao, Y. TBAI-catalyzed oxidative C–H functionalization: a new route to benzo[b]phosphole oxides. Chem. Commun. 2016, 52, 2815−2818. (d) Ouyang, X.; Song, R.; Liu, B.; Li, J. Synthesis of 3-alkyl spiro[4,5]trienones by copper-catalyzed oxidative ipso-annulation of activated alkynes with unactivated alkanes. Chem. Commun. 2016, 52, 2573−2576. (e) Kong, D.; Cheng, L.; Wu, H.; Li, Y.; Wang, D.; Liu, L. A metal-free yne-addition/1,4-aryl migration/decarboxylation cascade reaction of alkynoates with Csp3–H centers. Org. Biomol. Chem. 2016, 14, 2210–2217. (20) (a) Fan, X.; Rong, J.; Wu, H.; Zhou, Q.; Deng, H.; Tan, J. D.; Xue, C.; Wu, L.; Tao, H.; Wu, J. Eosin Y as a Direct Hydrogen-Atom Transfer Photocatalyst for the Functionalization of C-H Bonds. Angew. Chem. Int. Ed. 2018, 57, 8514–8518. Angew. Chem. 2018, 130, 8650–8654. (b) Mazzarella, D.; Crisenza, G. E. M.; Melchiorre, P. Asymmetric Photocatalytic C−H Functionalization of Toluene and Derivatives. J. Am. Chem. Soc. 2018, 140, 8439−8443. (c) Liu, H.; Ma, L.; Zhou, R.; Chen, X.; Fang, W.; Wu, J. One-Pot Photomediated Giese Reaction/Friedel−Crafts Hydroxyalkylation/Oxidative Aromatization To Access Naphthalene Derivatives from Toluenes and Enones. ACS Catal. 2018, 8, 6224−6229. (d) Lee, G. S.; Hong, S. H. Formal Giese addition of C(sp3)–H nucleophiles enabled by visible light mediated Ni catalysis of triplet enone diradicals. Chem. Sci. 2018, 9, 5810–5815. (e) Zhou, R.; Liu, H.; Tao, H.; Yu, X.; Wu, J. Metal-free direct alkylation of unfunctionalized allylic/benzylic sp3 C–H bonds via photoredox induced radical cation deprotonation. Chem. Sci. 2017, 8, 4654–4659. (f) Patil, S.; Chen, L.; Tanko, J. M. C–H Bond Functionalization with the Formation of a C−C Bond: A Free Radical Condensation Reaction Based on the Phthalimido-N-oxyl Radical. Eur. J. Org. Chem. 2014, 502–505. (g) Patil, S.; Chen, L.; Tanko, J. M. Effect of Lewis acids and low temperature initiators on the allyl transfer reaction involving phthalimido-N-oxyl radical. Tetrahedron Lett. 2014, 55, 7029–7033. (21) Guo, L.; Wang, S.; Duan, X.; Zhou, S. Iron-catalyzed tandem cyclization of olefinic dicarbonyl compounds with benzylic Csp3– H bonds for the synthesis of dihydrofurans. Chem. Commun. 2015, 51, 4803–4806. (22) For selected examples, see: (a) Hu, A.; Guo, J.; Pan, H.; Zuo, Z. Selective functionalization of methane, ethane, and higher alkanes by cerium photocatalysis. Science 2018, 361, 668–672. (b) Trowbridge, A.; Reich, D.; Gaunt, M. J. Multicomponent synthesis of tertiary alkylamines by photocatalytic olefinhydroaminoalkylation. Nature 2018, 561, 522–527. (c) Guo, X.; Wenger, O. S. Reductive Amination by Photoredox Catalysis and Polarity-Matched Hydrogen Atom Transfer. Angew. Chem. Int. Ed. 2018, 57, 2469–2473. Angew. Chem. 2018, 130, 2494–2498. (d) Le, C.; Liang, Y.; Evans, R. W.; Li, X.; MacMillan, D. W. C. Selective sp3 C–H alkylation via polarity-match-based cross-coupling.
Nature 2017, 547, 79−83; For an early review: (e) Roberts, B. P. Polarity-reversal catalysis of hydrogen-atom abstraction reactions: concepts and applications in organic chemistry. Chem. Soc. Rev. 1999, 28, 25–35. (23) For recent reviews on the functionalization of unactivated olefins elucidating their electronic property, see: (a) Dhungana, R. K.; KC, S.; Basnet, P.; Giri, R. Transition Metal-Catalyzed Dicarbofunctionalization of Unactivated Olefins. Chem. Rec. 2018, 18, 1314–1340. (b) Dong, Z.; Ren, Z.; Thompson, S. J.; Xu, Y.; Dong, G. Transition-metal-catalyzed C–H alkylation using alkenes. Chem. Rev. 2017, 117, 9333−9403. (c) Lan, X.; Wang, N.; Xing, Y. Recent Advances in Radical Difunctionalization of Simple Alkenes. Eur. J. Org. Chem. 2017, 5821–5851. (d) Deb, A.; Maiti, D. Emergence of Unactivated Olefins for the Synthesis of Olefinated Arenes. Eur. J. Org. Chem. 2017, 1239–1252. (e) Coombs, J. R.; Morken, J. P. Catalytic enantioselective functionalization of unactivated terminal alkenes. Angew. Chem. Int. Ed. 2016, 55, 2636–2649. Angew. Chem. 2016, 128, 2682–2696. (24) Sattar, M.; Kumar, S. Palladium-Catalyzed Removable 8Aminoquinoline Assisted Chemo-and Regioselective Oxidative sp2-C–H/sp3-C–H Cross-Coupling of Ferrocene with Toluene Derivatives. Org. Lett. 2017, 19, 5960−5963. (25) Kubo, T.; Aihara, Y.; Chatani, N. Pd (II)-catalyzed Chelation-assisted Cross Dehydrogenative Coupling between Unactivated C(sp3)–H Bonds in Aliphatic Amides and Benzylic C– H Bonds in Toluene Derivatives. Chem. Lett. 2015, 44, 1365–1367. (26) Sun and co-workers reported an esterification of methyl arenes with carboxylic acids, yet mechanism investigations suggested that methyl arene radical coupled with coordinated carboxylate cations: Lu, B.; Zhu, F.; Sun, H.; Shen, Q. Esterification of the Primary Benzylic C–H Bonds with Carboxylic Acids Catalyzed by Ionic Iron(III) Complexes Containing an Imidazolinium Cation. Org. Lett. 2017, 19, 1132−1135. (27) (a) Yu, H.; Xuan, P.; Jiao, M.; Lin, J. Synthesis of 1,1Disubstituted N-Acyl Tetrahydroisoquinolines from Enamides by Cascade Radical Addition and Cyclization. Eur. J. Org. Chem. 2018, 4565–4570. (b) Wang, J.; Sang, R.; Chong, X.; Zhao, Y.; Fan, W.; Li, Z.; Zhao, J. Copper-catalyzed radical cascade oxyalkylation of olefinic amides with simple alkanes: highly efficient access to benzoxazines. Chem. Commun. 2017, 53, 7961–7964. (c) Yang, J.; Zhang, J.; Guo, L. Copper-catalyzed oxidative cyclization of vinyl azides with benzylic Csp3–H bonds for the synthesis of substituted phenanthridines. Org. Biomol. Chem. 2016, 14, 9806–9813. (28) Wang, L.; Xiong, W.; Peng, Y.; Ding, Q. Iron-catalyzed cascade addition/cyclization of 2-biphenyl isocyanides with toluenes: a highly efficient approach to 6-benzylated phenanthridines. Org. Biomol. Chem. 2018, 16, 8837–8844. (29) (a) Li, Z.; Zhang, Y.; Zhang, L.; Liu, Z. Free-Radical Cascade Alkylarylation of Alkenes with Simple Alkanes: Highly Efficient Access to Oxindoles via Selective (sp3)C–H and (sp2)C–H Bond Functionalization. Org. Lett. 2014, 16, 382−385. (b) Zhou, S.; Guo, L.; Wang, H.; Duan, X. Copper-Catalyzed Oxidative Benzylarylation of Acrylamides by Benzylic C−H Bond Functionalization for the Synthesis of Oxindoles. Chem. Eur. J. 2013, 19, 12970–12973. (c) Zhou, M.; Wang, C.; Song, R.; Liu, Y.; Wei, W.; Li, J. Oxidative 1,2difunctionalization of activated alkenes with benzylic C(sp3)–H bonds and aryl C(sp2)–H bonds. Chem. Commun. 2013, 49, 10817– 10819. (30) Zhou, S.; Guo, L.; Wang, S.; Duan, X. Copper-catalyzed tandem oxidative cyclization of cinnamamides with benzyl hydrocarbons through cross-dehydrogenative coupling. Chem. Commun. 2014, 50, 3589−3591. (31) (a) Pan, C.; Yang, Z.; Gao, D.; Yu, J. Metal-free oxidative radical cascade addition/oxobutylation of unactivated alkenes with acetone towards 3-(3-oxobutyl)indolines. Org. Biomol. Chem. 2018, 16, 6035–6038. (b) Pan, C.; Gao, D.; Yang, Z.; Wu, C.; Yu, J. Metal-free oxidative radical cascade addition/oxobutylation of
13 ACS Paragon Plus Environment
The Journal of Organic Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
unactivated alkenes with acetone towards 3-(3oxobutyl)indolines. Org. Biomol. Chem. 2018, 16, 6035–6038. (c) Zhang, H.; Chen, P.; Liu, G. Palladium-Catalyzed Oxidative Arylalkylation of Unactivated Alkenes: Dual C–H Bond Cleavage of Anilines and Acetonitrile. Synlett 2012, 23, 2749-2752. (32) (a) Li, Y.; Chang, Y.; Li, Y.; Cao, C.; Yang, J.; Wang, B.; Liang, D. Iron-Catalyzed exo-Selective Synthesis of Cyanoalkyl Indolines via Cyanoisopropylarylation of Unactivated Alkenes. Adv. Synth. Catal. 2018, 360, 2488–2492. (b) Liang, D.; Dong, Q.; Xu, P.; Dong, Y.; Li, W.; Ma, Y. Synthesis of CF3CH2‑Containing Indolines by Transition-Metal-Free Aryltrifluoromethylation of Unactivated Alkenes. J. Org. Chem. 2018, 83, 11978−11986. (c) Liang, D.; Ge, D.; Lv, Y.; Huang, W.; Wang, B.; Li, W. Silver-Catalyzed Radical Arylphosphorylation of Unactivated Alkenes: Synthesis of 3‑Phosphonoalkyl Indolines. J. Org. Chem. 2018, 83, 4681–4691. (d) Liang, D.; Li, Y.; Gao, S.; Li, R.; Li, X.; Wang, B.; Yang, H. Amideassisted radical strategy: metal-free direct fluorination of arenes in aqueous media. Green Chem. 2017, 19, 3344–3349. (33) Lv, L.; Qi, L.; Guo, Q.; Shen, B.; Li, Z. Iron-Catalyzed Divergent Tandem Radical Annulation of Aldehydes with Olefins toward Indolines and Dihydropyrans. J. Org. Chem. 2015, 80, 12562–12571. (34) (a) Dadashpour, S.; Emami, S. Indole in the target-based design of anticancer agents: A versatile scaffold with diverse mechanism. Eur. J. Med. Chem. 2018, 150, 9−29. (b) Chadha, N.; Silakari, O. Indoles as therapeutics of interest in medicinal chemistry: Bird's eye view. Eur. J. Med. Chem. 2017, 134, 159−184. (c) Sugimoto, S.; Naganuma, M.; Kanai, T. Indole compounds may be promising medicines for ulcerative colitis. J. Gastroenterol. 2016, 51, 853−861. (d) Sravanthi, T. V.; Manju, S. L. Indoles—a promising scaffold for drug development. Eur. J. Pharm. Sci. 2016, 91, 1−10. (35) For recent reviews on the construction of indolic scaffolds: (a) Nagarajua, K.; Ma, D. Oxidative coupling strategies for the synthesis of indole alkaloids. Chem. Soc. Rev. 2018, 47, 8018−8029. (b) Xu, Z.; Wang, Q.; Zhu, J. Metamorphosis of cycloalkenes for the divergent total synthesis of polycyclic indole alkaloids. Chem. Soc. Rev. 2018, 47, 7882−7898. (c) Wang, Y.; Xie, F.; Lin, B.; Cheng, M.; Liu, Y. Synthetic Approaches to Tetracyclic Indolines as Versatile Building Blocks of Diverse Indole Alkaloids. Chem. Eur. J. 2018, 24, 14302–14315. (d) Kirillova, M. S.; Miloserdov, F. M.; Echavarren, A. M. Total syntheses of pyrroloazocine indole alkaloids: challenges and reaction discovery. Org. Chem. Front. 2018, 5, 273−287. (36) For recent examples, see: (a) Zhou, Y.; Lin, L.; Liu, X.; Hu, X.; Lu, Y.; Zhang, X.; Feng, X. Catalytic Asymmetric Diels–Alder Reaction/[3,3] Sigmatropic Rearrangement Cascade of 1Thiocyanatobutadienes. Angew. Chem. Int. Ed. 2018, 57, 9113– 9116. Angew. Chem. 2018, 130, 9251–9254. (b) Chen, X.; Xiong, J.; Liu, Q.; Li, S.; Sheng, H.; von Essen, C.; Rissanen, K.; Enders, D. Control of N-Heterocyclic Carbene Catalyzed Reactions of Enals: Asymmetric Synthesis of Oxindole--Amino Acid Derivatives. Angew. Chem. Int. Ed. 2018, 57, 300–304. Angew. Chem. 2018, 130, 306–310. (c) Chen, S.; Ma, W.; Yan, Z.; Zhang, F.; Wang, S.; Tu, Y.; Zhang, X.; Tian, J. Organo-Cation Catalyzed Asymmetric Homo/Heterodialkylation of Bisoxindoles: Construction of Vicinal All-Carbon Quaternary Stereocenters and Total Synthesis of ()Chimonanthidine. J. Am. Chem. Soc. 2018, 140, 10099–10103. (d) Wang, S.; Guo, Z.; Chen, S.; Jiang, Y.; Zhang, F.; Liu, X.; Chen, W.; Sheng, C. Organocatalytic Asymmetric Synthesis of SpiroTetrahydrothiophene Oxindoles Bearing Four Contiguous Stereocenters by One-Pot Michael-Henry-Cascade-Rearrangement Reactions. Chem. Eur. J. 2018, 24, 62–66. (e) Curti, C.; Battistini, L.; Sartori, A.; Rassu, G.; Pelosi, G.; Lombardo, M.; Zanardi, F. (E)-3(Alkoxycarbonyl-2-Alkyliden)-2-Oxindoles: Multidentate Pronucleophiles for the Organocatalytic, Vinylogous Michael Addition to Nitroolefins. Adv. Synth. Catal. 2018, 360, 711–721.
Page 14 of 15
(37) For a review, see: Chen, J.; Yu, X.; Xiao, W. Tandem radical cyclization of N-arylacrylamides: an emerging platform for the construction of 3,3-disubstituted oxindoles. Synthesis 2015, 47, 604−629. (38) (a) Zheng, C.; You, S. Catalytic asymmetric dearomatization by transition-metal catalysis: a method for transformations of aromatic compounds. Chem 2016, 1, 830–857. (b) Zhuo, C.; Zheng, C.; You, S. Transition-metal-catalyzed asymmetric allylic dearomatization reactions. Acc. Chem. Res. 2014, 47, 2558–2573. (c) Ding, Q.; Zhou, X.; Fan, R. Recent advances in dearomatization of heteroaromatic compounds. Org. Biomol. Chem. 2014, 12, 4807−4815. (d) Roche, S. P.; Porco, J. A., Jr. Dearomatization strategies in the synthesis of complex natural products. Angew. Chem. Int. Ed. 2011, 50, 4068–4093. Angew. Chem. 2011, 123, 4154–4179. (39) For recent examples: (a) Wang, L.; Li, S.; Blümel, M.; Puttreddy, R.; Peuronen, A.; Rissanen, K.; Enders, D. Switchable Access to Different Spirocyclopentane Oxindoles by NHeterocyclic Carbene Catalyzed Reactions of Isatin-Derived Enals and N-Sulfonyl Ketimines. Angew. Chem. Int. Ed. 2017, 56, 8516– 8521. Angew. Chem. 2017, 129, 8636–8641. (b) Katayev, D.; Kajita, H.; Togni, A. Magnesium-Catalyzed Electrophilic Trifluoromethylation: Facile Access to All-Carbon Quaternary Centers in Oxindoles. Chem. Eur. J. 2017, 23, 8353–8357. (c) Filatov, A. S.; Knyazev, N. A.; Molchanov, A. P.; Panikorovsky, T. L.; Kostikov, R. R.; Larina, A. G.; Boitsov, V. M.; Stepakov, A. V. Synthesis of Functionalized 3-Spiro [cyclopropa[a]pyrrolizine]and 3-Spiro[3-azabicyclo[3.1.0]hexane]oxindoles from Cyclopropenes and Azomethine Ylides via [3 2]-Cycloaddition. J. Org. Chem. 2017, 82, 959−975. (d) Li, T.; Cheng, B.; Fan, S.; Wang, Y.; Lu, L.; Xiao, W. Highly Stereoselective [32] Cycloadditions of Chiral Palladium-Containing N1-1,3-Dipoles: A Divergent Approach to Enantioenriched Spirooxindoles. Chem. Eur. J. 2016, 22, 6243–6247. (e) Zhao, B.; Du, D. Organocatalytic cascade Michael/Michael reaction for the asymmetric synthesis of spirooxindoles containing five contiguous stereocenters. Chem. Commun. 2016, 52, 6162–6165. (40) Studer, A.; Curran, D. P. Catalysis of Radical Reactions: A Radical Chemistry Perspective. Angew. Chem. Int. Ed. 2016, 55, 58–102. Angew. Chem. 2016, 128, 58–106. (41) (a) Gilmore, K.; Mohamed, R. K.; Alabugin, I. V. The Baldwin rules: revised and extended. WIREs Comput. Mol. Sci. 2016, 6, 487–514. (b) Baldwin, J. K. Rules for ring closure. J. Chem. Soc. Chem. Commun. 1976, 734–736. (c) Baldwin, J. K.; Thomas, R. C.; Kruse, L. I.; Silberman, L. Rules for ring closure: ring formation by conjugate addition of oxygen nucleophiles. J. Org. Chem. 1977, 42, 3846–3852. (42) For some examples, see: (a) Nandi, R. K.; Perez-Luna, A.; Gori, D.; Beaud, R.; Guillot, R.; Kouklovsky, C.; Gandon, V.; Vincenta, G. Triflic Acid as an Efficient Brønsted Acid Promoter for the Umpolung of N-Ac Indoles in Hydroarylation Reactions. Adv. Synth. Catal. 2018, 360, 161–172. (b) Bosset, C.; Beucher, H.; Bretel, G.; Pasquier, E.; Queguiner, L.; Henry, C.; Vos, A.; Edwards, J. P.; Meerpoel, L.; Berthelot, D. Minisci-Photoredox-Mediated Heteroarylation of N-Protected Secondary Amines: Remarkable Selectivity of Azetidines. Org. Lett. 2018, 20, 6003−6006. (c) Okugawa, N.; Moriyama, K.; Togo, H. Introduction of Quinolines and Isoquinolines onto Nonactivated -C–H Bond of Tertiary Amides through a Radical Pathway. J. Org. Chem. 2017, 82, 170−178. (d) Wang, J.; Li, J.; Huang, J.; Zhu, Q. Transition MetalFree Amidoalkylation of Benzothiazoles and Amidoalkylarylation of Activated Alkenes with N,N-Dialkylamides. J. Org. Chem. 2016, 81, 3017−3022. (43) Wu, Z.; Li, S.; Xu, H. Synthesis of N-Heterocycles by Dehydrogenative Annulation of N-Allyl Amides with 1,3Dicarbonyl Compounds. Angew. Chem. Int. Ed. 2018, 57, 14070−14074. Angew. Chem. 2018, 130, 14266−14270.
14 ACS Paragon Plus Environment
Page 15 of 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
The Journal of Organic Chemistry
(44) Pace, V.; Castoldi, L.; Hernáiz, M. J.; Alcántara, A. R.; Holzer, W. Chemoselective oxidative hydrolysis of EWG protected arylamino vinyl bromides to -arylamino-′-bromoacetones. Tetrahedron Lett. 2013, 54, 4369−4372.
15 ACS Paragon Plus Environment