Nitration and Cyclization of Arene-Alkynes: An ... - ACS Publications

Subscriber access provided by University of South Dakota

Note

Nitration and Cyclization of AreneAlkynes: An Access to 9-Nitrophenathrenes Wangsheng Liu, Yanbin Zhang, and Hao Guo J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.8b01201 • Publication Date (Web): 03 Aug 2018 Downloaded from http://pubs.acs.org on August 4, 2018

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 25 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

Nitration and Cyclization of Arene-Alkynes: An Access to 9-Nitrophenathrenes

Wangsheng Liu,† Yanbin Zhang,† and Hao Guo*,†,‡

†

Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200438,

P.

R.

China.

Tel:

+86-21-31249190,

Fax:

+86-21-31249190,

E-mail:

[email protected] ‡

Academy for engineering and technology, Fudan University, 220 Handan Road,

Shanghai, 200433, P. R. China Table of Contents

Keywords: Nitration, Cyclization, Iron, Nitrogen Dioxide, Phenanthrene

ABSTRACT: A nitration and cyclization of arene-alkynes has been developed, affording 9-nitrophenathrenes efficiently. This reaction probably proceeds via addition of the nitrogen dioxide to the alkyne moiety, intramolecular radical addition of vinyl radical to one aryl ring, oxidation of radical intermediate into carbocation species, and elimination of a proton. In this transformation, Fe(NO3)3 was used as both nitro source 1

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

Page 2 of 25

and oxidant.

Nitroolefins are a prominent class of molecules, existing widely in agrochemicals,1 pharmaceuticals,2 and natural products.3 In organic synthesis, nitroolefins are also ubiquitous building blocks.4 One of the most representative synthetic methods to obtain nitroolefins is based on the addition of nitrogen dioxide to alkene, after which elimination of a hydrogen/proton from the resulting alkyl radical intermediate gives the nitroolefin product5 (Scheme 1). However, methods for constructing nitroalkenes via 2-nitrovinyl species generated from the addition of nitrogen dioxides to alkynes are rare, since 2-nitrovinyl intermediate is highly unstable and has high reactivity and a short lifetime.6 Normally, there are two main ways to realize such a transformation. One is the intermolecular radical trapping reaction which remained undeveloped until the last decade.6-7 In this way, 2-nitrovinyl radicals can be captured by iodine or TEMPO, forming polysubstituted nitroolefins (Scheme 2a). The other is the intramolecular radical trapping reaction, in which 2-nitrovinyl radicals firstly undergo an radical cyclization when an unsaturated bond is incorporated at an appropriate position.8 In this way, the resulting alkyl radical intermediate will be further oxidized by TEMPO to enable the elimination of a proton to afford the final products (Scheme 2b). Scheme 1. Nitration of alkenes

2


Page 3 of 25 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


Scheme 2. Nitration of alkynes

Direct accesses to phenanthrene derivatives or 1,2-dihydronaphthalene derivatives from 4-arylalkynes have been well studied.9 Various functional groups, such as halogen,10 sulfide,11 selenium,12 tellurium,12 sulfone,13 and trifluoromethyl,14 can be introduced into the final products (Scheme 3). In most cases of such a transformation, the first step undergoes via the addition of the positive ion into the alkyne moiety.10-12 Only trifluoromethylation and sulfone reactions proceed via radical addition initiated procedure.13-14 Obviously, radical addition initiated reactions in this field are less studied. To the best of our knowledge, nitration and cyclization of 4-arylalkynes affording 9-nitrophenanthrene derivatives has not been reported. Based on our research interest on construction of 9-functionalized phenanthrenes,15 we did research on Fe(NO3)3-participated nitration and cyclization of arene-alkynes which affords 9-nitrophenanthrenes efficiently. Herein, we wish to report our recent observation in this field. Scheme 3. Cyclization and functionalization of 4-arylalkynes 3



When

optimizing

the

reaction

Page 4 of 25

conditions,

2-((4-methoxyphenyl)ethynyl)-1,1'-biphenyl 1a was chosen as the model substrate and Fe(NO3)3·9H2O was applied as both nitro source and oxidant. We firstly examined the solvent effect carefully. As shown in table 1, the desired reaction in Et3N, acetone, DCM, toluene, DCE, or MeOH did not proceed at all (entries 1-6, Table 1). 10-(4-Methoxyphenyl)-9-nitrophenanthrene 2a could be observed in a low yield, when THF or MeCN was used as the solvent (entries 7 and 8, Table 1). To our delight, 2a was obtained in a higher yield, when MeNO2 was used as the solvent (entry 9, Table 1). Thus, MeNO2 was chosen as the best solvent. Next, the amount of Fe(NO3)3·9H2O was optimized. Increased amount led to a decreased yield (entries 10 and 11, Table 1). When 2 equivalents of Fe(NO3)3·9H2O was applied, 2a was formed in a 71% isolated yield (entry 12, Table 1). Further reducing the amount of Fe(NO3)3·9H2O resulted in a much lower yield of 2a (entries 13 and 14, Table 1). Finally, temperature effect was studied. No reaction occurred at lower temperature (entry 15, Table 1). When higher temperature was applied, the reaction speed was obviously accelerated, however, the corresponding yield was lower (entries 16 and 17, Table 1). Thus, Condition A (Fe(NO3)3·9H2O (2 equiv.), MeNO2, and 30 oC) was applied for the following studies. Table 1. Optimization of the reaction conditionsa 4


Page 5 of 25 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


Fe(NO3)3·9H2O Entry

Temperature

Solvent

NMR Yield Time (h)

(equiv.)

o

of 2a (%)b

( C)

1

Et3N

3

30

24

0 (80)c

2

Acetone

3

30

24

0 (63)c

3

DCM

3

30

24

0 (100)c

4

Toluene

3

30

24

0 (99)c

5

DCE

3

30

24

0 (85)c

6

MeOH

3

30

24

0 (96)c

7

THF

3

30

24

15 (72)c

8

MeCN

3

30

10

32 (0)c

9

MeNO2

3

30

3

61 (0)c

10

MeNO2

4

30

3

55 (0)c

11

MeNO2

5

30

3

37 (0)c

12

MeNO2

2

30

3.5

73 (0)c (71)d

13

MeNO2

1

30

5

52 (0)c

14

MeNO2

0.5

30

48

26 (32)c

15

MeNO2

2

0

7

0 (100)c

16

MeNO2

2

60

1

53 (0)c

5



17 a

MeNO2

2

100

Page 6 of 25

0.5

10 (0)c

A solution of 1a (0.2 mmol) and Fe(NO3)3·9H2O in anhydrous solvent (3 mL) was

stirred under argon atmosphere. b The yields were determined by 1H NMR (400 MHz) analysis of the crude reaction mixture with CH2Br2 (0.2 mmol) as internal standrad.

c

NMR recovery yield of 1a. d Isolated yield of 2a. With optimized reaction conditions in hand, we started to investigate the scope of this reaction (Table 2). A series of mono-, di-, or tri-substituted arene-alkynes were tested under Condition A. We firstly studied the electronic effect of monosubstituted arene-alkynes. With strong electron-donating groups, like methoxy and acetoxy, the reaction completed in a short time, generating the desired products (2a and 2b) in good yields. Weak electron-donating group, like t-butyl and phenyl, substituted reactants also gave the corresponding products (2c and 2d) in moderate yields. When substrates with weak electron-withdrawing group, like chlorine, was tested, higher temperature was required to complete the transformation (2f and 2g). Reactions for substrates bearing strong electron-withdrawing groups, such as nitro and cyano, gave similar results (2h and 2i). Finally, some di- or trisubstituted substrates were applied under Condition A, multi-substituted nitrophenathrenes were formed in good yields (2j-l). Table 2. Scope of this reactiona

6


Page 7 of 25 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


a

2a, 30 oC, 3.5 h, 71%

2b, 30 oC, 12 h, 70%

2c, 30 oC, 12 h, 68%

2d, 20 oC, 48 h, 65%

2e, 30 oC, 72 h, 75%

2f, 45 oC, 36 h, 50%

2g, 45 oC, 36 h, 54%

2h, 30 oC, 47 h, 57%

2i, 30 oC, 47 h, 55%

2j, 30 oC, 4 h, 75%

2k, 30 oC, 12.5 h, 62%

2l, 30 oC, 12.5 h, 68%

A solution of 1a (0.2 mmol) and Fe(NO3)3·9H2O (2 equiv.) in anhydrous MeNO2 (3

mL) was stirred under argon atmosphere. Isolated yield was reported. Further studies indicated that this reaction also worked with heteroaromatic substituents

in

the

alkyne

moiety

(Scheme

4).

When

2-(4-pyridylethynyl)-1,1'-biphenyl 3a was applied, higher temperature was required, generating the desired product 4a in a moderate yield. The reaction of 7



Page 8 of 25

2-(3-thienylethynyl)-1,1'-biphenyl 3b must be carried out at 0 oC, affording the corresponding cyclized product 4b in a low yield. Scheme 4. The reaction with heteroaromatic substituents in the alkyne moiety

Next, the reactivities of some arene-alkyne substrates that bear O, N, and simple methylene linkers were tested (Table 3). The reaction of phenyl 3-phenylpropiolate 5a gave the corresponding 3-nitro-4-phenyl-2H-chromen-2-one 6a in a 34% isolated yield. However, the reaction temperature must be increased to 100 oC. The reaction n of N,3-diphenylpropiolamide 5b under Condition A did not proceed at all. Then we attempted to run this reaction at 60 oC. Disappointingly, although 5b was totally consumed, no desired product was observed. For but-1-yne-1,4-diyldibenzene 5c, no desire product was formed either under Condition A or at 0 oC. Table 3. Reaction of other substratesa

8


Page 9 of 25 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


a

6a, 30 oC, 11 h, NR

6b, 30 oC, 12 h, NR

6c, 30 oC, 11 h, trace

100 oC, 10 h, 34%

60 oC, 12 h, 0%

0 oC, 24 h, traceb

A solution of 5 (0.2 mmol) and Fe(NO3)3·9H2O (2 equiv.) in anhydrous MeNO2 (3

mL) was stirred under argon atmosphere. Isolated yield was reported.

b

Some

unidentified byproducts were formed. Furthermore, gram-scale application was successfully achieved. As shown in Scheme 4, 1000 mg of 1a could be efficiently transferred into 2a in a 68% isolated yield. This example clearly demonstrated the operationally facile of this method for organic synthesis. Scheme 5. Gram scale reaction of 1a

To gain further insight into the reaction mechanism, radical scavenger (TEMPO), was added into the reaction system. When 5 equivalents of TEMPO was used, the reaction was suppressed and only trace amount of 2a was obtained (Scheme 5), suggesting that a radical intermediate might be involved in the key reaction step.16 Scheme 6. Control reaction with 5 equivlents of TEMPO 9



Page 10 of 25

Based on the above results and literature precedents, a plausible mechanism was proposed as shown in Scheme 7. Firstly, nitrogen dioxide was generated by thermal decomposition of Fe(NO3)3·9H2O.5c,17 Secondly, the in suit generated nitrogen dioxide would give rise to two regiosiomeric alkenyl radicals 7 and 7’ by attack at either carbon of the alkyne moiety. Thirdly, the favored six-membered ring radical intermediate 8 and the disfavored five-membered ring radical intermediate 8’ were formed from the corresponding intramolecular radical addition of 7 and 7’, respectively. Notably, the radical addition steps are generally reversible, which led to the result that the favored intermediate 8 was afforded as the sole product. Subsequently, the cyclohexadienyl radical 8 was oxidized by Fe3+ to form cyclohexadienyl cation 9.18 Notably, this single electron oxidation step would be the product-determining step. Finally, 9 would easily eliminate a proton to form the final product 2.14a Scheme 7. Proposed mechanism

10


Page 11 of 25 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


In summary, we have developed a new strategy of nitration and cyclization of a series of arene-alkynes under mild conditions, which provides a novel and practical protocol for the synthesis of 9-nitrophenathrenes. The whole transformation was initiated by the radical addition of nitroxyl radical to the alkyne moiety. In this reaction Fe(NO3)3·9H2O was used as both nitro source and oxidant. EXPERIMENTAL SECTION General Methods. 1H (400 MHz) and 13C (100 MHz) NMR spectra of samples in CDCl3 were recorded on an AVANCE III 400 spectrometer. IR spectra were recorded on a Avatar 360 FT-IR spectrometer. HRMS (EI) determinations were carried out on a Waters GCT CA176 spectrometer. HRMS (ESI) determinations were carried out on a Bruker Daltonics APEXIIITM ESI-FTICRMS spectrometer. Melting points were determined on a WRS-2 apparatus. Anhydrous MeNO2 was distilled with CaSO4. Compounds 1a,15 1b,19 1d,15 1e,15 1f,15 1g,15 1h,15 1i,20 1j,15 1k,19 1l,19 5a,21 5b,21 and 5c22 were prepared according to literature procedures. General Procedure for the synthesis of arene-alkynes. 2-Iodo-1,1'-biphenyl (1 equiv.), aromatic alkyne (1 equiv.), Pd(PPh3)4 (5 mol%), CuI (5 mol%), and Et3N (50 11



Page 12 of 25

mL) were added subsequently into a 100 mL of three-necked flask. The resulting mixture was refluxed and completed as monitored by TLC. Then it was cooled to room temperature. The solvent was removed and the residue was purified by flash chromatography on silica gel to afford 1c, 3a or 3b. 2-((4-tert-butylphenyl)ethynyl)-1,1'-biphenyl (1c). Liquid (827 mg, 62%); 1H NMR (400 MHz, CDCl3) δ 7.90-7.55 (m, 3 H), 7.52-7.12 (m, 10 H), 1.29 (s, 9 H); 13C NMR (100 MHz, CDCl3) δ 151.3, 143.8, 140.6, 132.7, 131.1, 129.42, 129.39, 128.3, 127.8, 127.4, 127.0, 125.2, 121.8, 120.4, 92.4, 88.7, 34.7, 31.1; IR (neat) 2223, 2194, 1604, 1516, 1473, 1433 cm-1; HRMS (EI) calcd for C24H22 (M+) 310.1722, found 310.1724. 2-(4-Pyridylethynyl)-1,1'-biphenyl (3a).20 Solid (0.705 g, 28%); 1H NMR (400 MHz, CDCl3) δ 8.52 (d, J = 4.8 Hz, 2 H), 7.72-7.53 (m, 3 H), 7.52-7.39 (m, 5 H), 7.37-7.29 (m, 1 H), 7.15 (d, J = 4.8 Hz, 2 H). 2-(3-Thienylethynyl)-1,1'-biphenyl (3b). Liquid (0.724 g, 28%); 1H NMR (400 MHz, CDCl3) δ 7.69-7.54 (m, 3 H), 7.46-7.24 (m, 7 H), 7.20-7.11 (m, 1 H), 6.98 (dd, J = 5.0, 1.1 Hz, 1 H);

13

C NMR (100 MHz, CDCl3) δ 143.7, 140.5, 132.6, 129.5,

129.4, 129.3, 128.4, 128.2, 127.8, 127.4, 127.0, 125.2, 122.4, 121.5, 88.8, 87.5; IR (neat) 2209, 1598, 1575, 1527, 1476, 1433 cm-1; HRMS (EI) calcd for C18H13S (M + H+) 261.0732, found 261.0733. General

procedure

for

reactions

under

Condition

A.

Substituted

2-phenylethynyl-1,1'-biphenyl 1a-1l (0.20 mmol), Fe(NO3)3·9H2O (0.40 mmol), and anhydrous nitromethane (3 mL) were added subsequently to a 25 mL of dry glass reaction tube which was equipped with a magnetic stirrer. The mixture was stirred at 12


Page 13 of 25 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


30 oC. The reaction was completed as monitored by TLC. The resulting reaction mixture was filtered. Then, the solvent was removed and the residue was purified by flash column chromatography on silica gel (eluent: petroleum ether : ethyl acetate 100:1) to afford 2a-2l, 4a, 4b, 6a or 6c. The Gram-Scale Synthesis. 2-((4-methoxyphenyl)ethynyl)-1,1'-biphenyl 1a (1000 mg, 3.52 mmol), Fe(NO3)3·9H2O (2.841 g, 7.03 mmol), and anhydrous nitromethane (6 mL) were added subsequently to a 25 mL of dry glass reaction tube which was equipped with a magnetic stirrer. The mixture was stirred at 30 oC. The reaction was completed after 4 hours as monitored by TLC (eluent: petroleum ether : ethyl acetate = 100:1). The resulting reaction mixture was filtered. Then, the solvent was removed and the residue was purified by flash column chromatography on silica gel (eluent: petroleum ether : ethyl acetate = 100:1) to afford 2a as a solid (788 mg, 68%) 10-(4-methoxyphenyl)-9-nitrophenanthrene (2a). Solid (47 mg, 71%); mp 159.7-159.9 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.75 (t, J = 7.4 Hz, 2 H), 7.86-7.61 (m, 5 H), 7.59-7.48 (m, 1 H), 7.35 (d, J = 8.8 Hz, 2 H), 7.04 (d, J = 8.4 Hz, 2 H), 3.88 (s, 3 H); 13C NMR (100 MHz, CDCl3) δ 159.9, 131.1, 130.6, 130.38, 130.35, 129.8, 128.6, 128.4, 128.3, 128.1, 127.6, 125.6, 122.9, 122.81, 122.78, 122.5, 114.1, 55.3; IR (neat) 1607, 1558, 1537, 1433, 1388 cm-1; HRMS (ESI) calcd for C21H15NO3Na (M + Na+) 352.0944, found 352.0944. 10-(4-Acetylphenyl)-9-nitrophenanthrene

(2b).

Solid

(50

mg,

70%);

mp

193.5-193.6 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.78 (t, J = 7.6 Hz, 2 H), 7.90-7.67 (m, 4 H), 7.66-7.51 (m, 2 H), 7.45 (d, J = 8.4 Hz, 2 H), 13



Page 14 of 25

7.27 (d, J = 8.4 Hz, 2 H), 2.37 (s, 3 H); 13C NMR (100 MHz, CDCl3) δ 169.2, 151.1, 131.1, 131.0, 130.5, 130.4, 130.2, 129.1, 128.62, 128.56, 128.4, 127.8, 123.0, 122.9, 122.7, 121.8, 21.2; IR (neat) 1766, 1592, 1528, 1503, 1488, 1452, 1430, 1406, 1378, 1366 cm-1; HRMS (EI) calcd for C22H15NO4 (M+) 357.1001, found 357.0995. 10-(4-tert-Butylphenyl)-9-nitrophenanthrene (2c). Solid (48 mg, 68%); mp 172.7-172.8 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.78 (t, J = 7.9 Hz, 2 H), 7.87-7.63 (m, 5 H), 7.62-7.47 (m, 3 H), 7.41-7.31 (m, 2 H), 1.40 (s, 9 H); 13C NMR (100 MHz, CDCl3) δ 151.7, 147.1, 130.5, 130.4, 130.1, 129.6, 129.0, 128.8, 128.4, 128.3, 128.1, 127.6, 125.5, 122.9, 122.8, 122.6, 34.8, 31.3; IR (neat) 1619, 1595, 1561, 1531, 1507, 1446, 1427, 1378 cm-1; HRMS (EI) calcd for C24H21NO2 (M+) 355.1572, found 355.1577. 9-Nitro-10-(4-phenylphenyl)phenanthrene

(2d).

Solid

(49

mg,

65%);

mp

195.6-195.8 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.80 (t, J = 7.2 Hz, 2 H), 7.86-7.65 (m, 9 H), 7.60 (t, J = 7.6 Hz, 1 H), 7.55-7.45 (m, 4 H), 7.40 (t, J = 7.4 Hz, 1 H);

13

C NMR (100 MHz, CDCl3) δ147.2, 141.7, 140.4, 132.5,

130.5, 130.4, 130.3, 129.8, 128.9, 128.7, 128.5, 128.4, 128.3, 127.74, 127.67, 127.3, 127.2, 123.0, 122.9, 122.7, 122.6; IR (neat) 1601, 1564, 1531, 1461, 1446, 1382 cm-1; HRMS (EI) calcd for C26H17NO2 (M+) 375.1254, found 375.1250. 9-Nitro-10-phenylphenanthrene (2e). Solid (45 mg, 75%); mp 213.1-213.2 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.78 (t, J = 7.6 Hz, 2 H), 7.86-7.67 (m, 4 H), 7.66-7.48 (m, 5 H), 7.47-7.37 (m, 2 H); 13C NMR (100 MHz, CDCl3) δ 133.6, 130.5, 130.4, 130.3, 130.0, 129.9, 128.9, 128.64, 128.59, 128.5, 14


Page 15 of 25 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


128.3, 128.2, 127.7, 122.9, 122.8, 122.7, 122.6; IR (neat) 1598, 1522, 1488, 1439, 1375 cm-1; HRMS (EI) calcd for C20H13NO2 (M+) 299.0946, found 299.0951. 10-(4-Chlorophenyl)-9-nitrophenanthrene

(2f).

Solid

(33

mg,

50%);

mp

196.4-196.9 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.78 (dd, J = 8.3, 5.1 Hz, 2 H), 7.87-7.66 (m, 4 H), 7.60-7.56 (m, 2 H), 7.52-7.48 (m, 2 H), 7.42-7.33 (m, 2 H); 13C NMR (100 MHz, CDCl3) δ 135.2, 132.1, 131.3, 130.6, 130.4, 129.9, 129.0, 128.8, 128.6, 128.48, 128.46, 128.3, 127.8, 123.0, 122.7, 122.6; IR (neat) 1531, 1488, 1446, 1375 cm-1; HRMS (EI) calcd for C20H12NO2Cl (M+) 333.0557, found 333.0561. 2-Chloro-10-nitro-9-phenylphenanthrene

(2g).

Solid

(36

mg,

54%);

mp

198.0-198.3 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.71 (d, J = 9.2 Hz, 2 H), 7.86-7.68 (m, 3 H), 7.66-7.47 (m, 5 H), 7.46-7.36 (m, 2 H);

13

C

NMR (100 MHz, CDCl3) δ 134.6, 133.3, 131.5, 130.2, 130.0, 129.8, 129.1, 128.91, 128.87, 128.8, 128.7, 128.0, 124.6, 123.8, 122.8, 122.0; IR (neat) 1598, 1531, 1482, 1443, 1378 cm-1; HRMS (EI) calcd for C20H12NO2Cl (M+) 333.0557, found 333.0550. 9-Nitro-10-(4-nitrophenyl)phenanthrene (2h). Solid (39 mg, 57%); mp 205.3-205.8 o

C (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.81 (d, J = 8.0 Hz,

2 H), 8.39 (d, J = 8.4 Hz, 2 H), 7.90-7.72 (m, 4 H), 7.70-7.55 (m, 3 H), 7.47 (d, J = 8.4 Hz, 1 H); 13C NMR (100 MHz, CDCl3) δ 148.3, 140.6, 131.2, 130.8, 130.5, 129.1, 128.96, 128.91, 128.7, 128.1, 127.9, 127.7, 123.8, 123.2, 123.1, 122.8, 122.3; IR (neat) 1671, 1592, 1522, 1446, 1430 cm-1; HRMS (EI) calcd for C20H12N2O4 (M+) 344.0792, found 344.0789. 15



10-(4-Cyanophenyl)-9-nitrophenanthrene

(2i).

Solid

Page 16 of 25

(36

mg,

55%);

mp

202.2-202.4 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.81 (dd, J = 8.4, 1.2 Hz, 2 H), 7.89-7.70 (m, 6 H), 7.69-7.52 (m, 3 H), 7.46 (dd, J = 8.4, 0.8 Hz, 1 H); 13C NMR (100 MHz, CDCl3) δ 138.7, 132.4, 130.9, 130.8, 130.5, 129.2, 128.90, 128.85, 128.7, 128.1, 128.03, 127.98, 123.2, 123.0, 122.8, 122.4, 118.3, 113.1; IR (neat) 2226, 1604, 1528, 1503, 1446, 1427 cm-1; HRMS (EI) calcd for C21H13N2O2 (M + H+) 325.0972, found 325.0971. 3-Methyl-9-(4-methoxyphenyl)-10-nitrophenanthrene (2j). Solid (52 mg, 75%); mp 173.1-173.5 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.75 (d, J = 8.0 Hz, 1 H), 8.56 (s, 1 H), 7.78-7.70 (m, 1 H), 7.68-7.60 (m, 2 H), 7.59-7.51 (m, 2 H), 7.35 (d, J = 8.8 Hz, 2 H), 7.04 (d, J = 8.8 Hz, 2 H), 3.89 (s, 3 H), 2.66 (s, 3 H); C NMR (100 MHz, CDCl3) δ 159.9, 138.3, 131.2, 130.8, 130.5, 130.1, 130.0, 128.7,

13

128.6, 128.1, 127.5, 125.7, 122.8, 122.7, 122.4, 120.8, 114.1, 55.3, 22.1; IR (neat) 1610, 1592, 1525, 1500, 1430 cm-1; HRMS (EI) calcd for C22H17NO3 (M+) 343.1208, found 343.1204. 6-Methyl-10-(4-methoxyphenyl)-2,9-dinitrophenanthrene (2k). Solid (48 mg, 62%); mp 254.2-254.5 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.86 (d, J = 9.2 Hz, 1 H), 8.68-8.51 (m, 2 H), 8.47 (dd, J = 9.2, 2.0 Hz, 1 H), 7.66 (s, 2 H), 7.34 (d, J = 8.4 Hz, 2 H), 7.07 (d, J = 8.8 Hz, 2 H), 3.92 (s, 3 H), 2.69 (s, 3 H); 13C NMR (100 MHz, CDCl3) δ 160.4, 146.6, 139.5, 133.9, 132.0, 131.2, 130.9, 129.5, 128.9, 124.5, 124.3, 124.0, 123.6, 122.9, 122.0, 121.7, 114.6, 55.3, 22.1; IR (neat) 1610, 1534, 1507, 1494, 1467, 1439 cm-1; HRMS (EI) calcd for C22H16N2O5 (M+) 16


Page 17 of 25 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


388.1059, found 388.1062. 2-Cyano-6-methyl-10-(4-methoxyphenyl)-9-nitrophenanthrene (2l). Solid (50 mg, 68%); mp 254.9-255.0 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.81 (d, J = 8.8 Hz, 1 H), 8.54 (s, 1 H), 7.99 (s, 1 H), 7.89 (d, J = 8.8 Hz, 1 H), 7.64 (s, 2 H), 7.31 (d, J = 8.8 Hz, 2 H), 7.06 (d, J = 8.8 Hz, 2 H), 3.91 (s, 3 H), 2.68 (s, 3 H);

13

C NMR (100 MHz, CDCl3) δ 160.3, 148.3, 139.3, 133.6, 132.5, 131.7, 131.1,

130.8, 129.6, 129.4, 128.0, 124.0, 123.2, 122.8, 121.7, 118.6, 114.5, 111.0, 55.4, 22.1; IR (neat) 2226, 1610, 1528, 1510, 1455, 1439 cm-1; HRMS (EI) calcd for C23H16N2O3 (M+) 368.1161, found 368.1164. 10-(4-Pyridyl)-9-nitrophenanthrene (4a). Solid (39 mg, 65%); mp 147.7-147.9 oC (ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 8.83 (s, 4 H), 7.95-7.74 (m, 4 H), 7.62 (t, J = 7.6 Hz, 1 H), 7.52 (d, J = 8.2 Hz, 1 H), 7.42 (s, 2 H); 13C NMR (100 MHz, CDCl3) δ 150.1, 130.5, 129.0, 128.9, 128.8, 128.7, 128.1, 128.0, 125.0, 123.2, 123.1, 122.9, 122.4; IR (neat) 1592, 1529, 1496, 1450 cm-1; HRMS (ESI) calcd for C19H13N2O2 (M + H+) 301.0978, found 301.0972. 10-(3-Thienylethynyl)-9-nitrophenanthrene (4b). Oil (19 mg, 31%); 1H NMR (400 MHz, CDCl3) δ 8.86-8.72 (m, 2 H), 7.86-7.67 (m, 5 H), 7.65-7.57 (m, 1 H), 7.55-7.43 (m, 2 H), 7.27-7.21 (m, 1 H);

13

C NMR (100 MHz, CDCl3) δ 132.9, 130.5, 130.33,

130.31, 129.9, 129.4, 128.9, 128.5, 128.3, 127.8, 126.15, 126.08, 125.5, 123.0, 122.9, 122.8, 122.6; IR (neat) 1601, 1529, 1496, 1450 cm-1; HRMS (EI) calcd for C18H12NO2S (M + H+) 306.0583, found 306.0582. 3-Nitro-4-phenyl-2H-chromen-2-one (6a). Solid (18 mg, 34%); mp 116.1-116.2 oC 17



Page 18 of 25

(ethyl acetate/petroleum ether); 1H NMR (400 MHz, CDCl3) δ 7.74-7.65 (m, 1 H), 7.60-7.52 (m, 3 H), 7.49 (d, J = 8.4 Hz, 1 H), 7.41-7.37 (m, 2 H), 7.34-7.29 (m, 2 H); 13

C NMR (100 MHz, CDCl3) δ 153.4, 152.9, 147.0, 134.1, 130.8, 129.2, 128.8, 127.9,

125.5, 117.9, 117.5; IR (neat) 1736, 1604, 1567, 1532, 1448 cm-1; HRMS (EI) calcd for C15H10NO4 (M + H+) 268.0604, found 268.0604. ASSOCIATED CONTENT Supporting Information 1

H NMR spectra of all the products.

13

C NMR spectra of all the products.

AUTHOR INFORMATION Corresponding Author * E-mail: [email protected] Notes The authors declare no competing financial interest. ACKNOWLEDGMENTS We greatly acknowledge the financial support from Fundamental Research Funds for the Central Universities, Pioneering Project of Academy for Engineering and Technology, Fudan University (gyy2017-002). REFERENCES (1) Jeschke, P.; Nauen, R. Neonicotinoids–from Zero to Hero in Insecticide Chemistry. Pest. Manag. Sci. 2008, 64, 1084-1098. (2) (a) Kim, J. H.; Kim, J. H.; Lee, G. E.; Lee, J. E.; Chung, I. K. Potent Inhibition of 18


Page 19 of 25 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


Human Telomerase by Nitrostyrene Derivatives. Mol. Pharmacol. 2003, 63, 1117-1124. (b) Reddy, M. A.; Jain, N.; Yada, D.; Kishore, C.; Vangala, J. R.; Reddy, P. S.; Addlagatta, A.; Kalivendi, S. V.; Sreedhar, B. Design and Synthesis of Resveratrol-Based Nitrovinylstilbenes as Antimitotic Agents. J. Med. Chem. 2011, 54, 6751-6760. (c) Safaei-Ghomi, J.; Babaei, P.; Shahbazi-Alavi, H.; Zahedi, S. Diastereoselective Synthesis of Trans-2,3-Dihydrofuro[3,2-c]coumarins by MgO Nanoparticles under Ultrasonic Irradiation J. Saudi Chem. Soc. 2017, 21, 929-937. (3) Ligon, J. M.; Hill, D. S.; Hammer, P. E.; Torkewitz, N. R.; Hofmann, D.; Kempf, H.-J.; Pe´e, K.-H. v. Natural Products with Antifungal Activity from Biocontrol Bacteria. Pest. Manag. Sci. 2000, 56, 688-695. (4) (a) Barrett, G. M.; Graboski, G. G. Conjugated Nitroalkenes: Versatile Intermediates in Organic Synthesis. Chem. Rev. 1986, 86, 751-762. (b) Alonso, D. A.; Baeza, A.; Chinchilla, R.; Gomez, C.; Guillena, G.; Pastor, I. M.; Ramon, D. J. Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes. Molecules 2017, 22, 895. (c) Figueroa-Valverde, L.; Díaz-Cedillo, F.; Pool-Gómez, E. G.-C. E.; Rosas-Nexticapa, M.; López-Ramos, M.; Vera-Escobedoa, M. I. Design and Synthesis of Two Triazoninecarbaldehyde Derivatives Using Several Chemical Tools. J. Saudi Chem. Soc. 2017, 22, 183-197. (d) Moradi, L.; Tadayon, M. Green Synthesis of 3,4-Dihydropyrimidinones Using Nano Fe3O4@meglumine Sulfonic Acid as a New Efficient Solid Acid Catalyst under Microwave Irradiation. J. Saudi Chem. Soc. 2018, 22, 66-75. (5) (a) Maity, S.; Naveen, T.; Sharma, U.; Maiti, D. Stereoselective Nitration of 19



Page 20 of 25

Olefins with tBuONO and TEMPO: Direct Access to Nitroolefins under Metal-free Conditions. Org. Lett. 2013, 15, 3384-3387. (b) Maity, S.; Manna, S.; Rana, S.; Naveen, T.; Mallick, A.; Maiti, D. Efficient and Stereoselective Nitration of Monoand Disubstituted Olefins with AgNO2 and TEMPO. J. Am. Chem. Soc. 2013, 135, 3355-3358. (c) Naveen, T.; Maity, S.; Sharma, U.; Maiti, D. A Predictably Selective Nitration of Olefin with Fe(NO3)3 and TEMPO. J. Org. Chem. 2013, 78, 5949-5954. (6) (a) Dutta, U.; Maity, S.; Kancherla, R.; Maiti, D. Aerobic Oxynitration of Alkynes with tBuONO and TEMPO. Org. Lett. 2014, 16, 6302-6305. (b) Yan, H.; Rong, G.; Liu,

D.;

Zheng,

Y.;

Chen,

J.;

Mao,

J.

Stereoselective

Intermolecular

Nitroaminoxylation of Terminal Aromatic Alkynes: Trapping Alkenyl Radicals by TEMPO. Org. Lett. 2014, 16, 6306-6309. (7) (a) Yusubov, M. S.; Perederina, I. A.; Filimonov, V. D.; Park, T.-H.; Chi, K.-W. A Facile Synthesis of α-Iodo-β-nitroalkenes from Alkynes Using I2/NO3- or KI/NO3-. Synth. Commun. 1998, 28, 833-836. (b) Hlekhlai, S.; Samakkanad, N.; Sawangphon, T.; Pohmakotr, M.; Reutrakul, V.; Soorukram, D.; Jaipetch, T.; Kuhakarn, C. Oxone®/KI-Mediated Nitration of Alkenes and Alkynes: Synthesis of Nitro- and β-Iodonitro-Substituted Alkenes. Eur. J. Org. Chem 2014, 7433-7442. (c) Xu, X.; Li, X.; Fan, Y.; Zhou, B.; Chen, K.; Wang, B. A Facile Synthesis of β-Iodonitro Alkenes via Iodonitration of Alkynes with tert-Butyl Nitrite and Iodine. Synlett. 2017, 28, 1657-1659. (8) (a) Hao, X. H.; Gao, P.; Song, X. R.; Qiu, Y. F.; Jin, D. P.; Liu, X. Y.; Liang, Y. M. Metal-free Nitro-carbocyclization of 1,6-Enynes with tBuONO and TEMPO. Chem. 20


Page 21 of 25 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


Commun. 2015, 51, 6839-6842. (b) Yang, X.-H.; Ouyang, X.-H.; Wei, W.-T.; Song, R.-J.; Li, J.-H. NitrativeSpirocyclization Mediated by TEMPO: Synthesis of Nitrated Spirocycles from N-Arylpropiolamides, tert-Butyl Nitrite and Water. Adv. Synth. Catal. 2015, 357, 1161-1166. (9) (a) Godoi, B.; Schumacher, R. F.; Zeni, G. Synthesis of Heterocycles via Electrophilic Cyclization of Alkynes Containing Heteroatom. Chem. Rev. 2011, 111, 2937-2980. (b) Palisse, A.; Kirsch, S. F. Metal-free Reactions of Alkynes via Electrophilic Iodocarbocyclizations. Org. Biomol. Chem. 2012, 10, 8041-8047. (c) Gao, P.; Song, X. R.; Liu, X. Y.; Liang, Y. M. Recent Developments in the Trifluoromethylation of Alkynes. Chem. Eur. J. 2015, 21, 7648-7661. (10) (a) Barluenga, J.; Trincado, M.; Marco-Arias, M.; Ballesteros, A.; Rubio, E.; Gonzalez, J. M. Intramolecular Iodoarylation Reaction of Alkynes: Easy Access to Derivatives of Benzofused Heterocycles. Chem. Commun. 2005, 2008-2010. (b) Yao, T.; Campo, M. A.; Larock, R. C. Synthesis of Polycyclic Aromatics and Heteroaromatics via Electrophilic Cyclization. J. Org. Chem. 2005, 70, 3511-3517. (c) Zhang, X.; Sarkar, S.; Larock, R. C. Synthesis of Naphthalenes and 2-Naphthols by the Electrophilic Cyclization of Alkynes. J. Org. Chem. 2006, 71, 236-243. (d) Likhar, P.; Racharlawar, S.; Karkhelikar, M.; Subhas, M.; Sridhar, B. Iodocyclization of N-Aryl-3-phenylpropiolamides by I2/CAN: A Convenient Route for the Selective Synthesis of Quinolin-2-ones. Synthesis. 2011, 2011, 2407-2414. (e) Mo, J.; Choi, W.; Min, J.; Kim, C. E.; Eom, D.; Kim, S. H.; Lee, P. H. ICl-Mediated Intramolecular Twofold Iodoarylation of Diynes and Diynyl Diethers and Amines: Synthesis of 21



Page 22 of 25

Bis(2H-hydronaphthalene and chromene) and 2H-Quinoline Bearing an Alkenyl Iodide Moiety. J. Org. Chem. 2013, 78, 11382-11388. (f) Grimaldi, T. B.; Lutz, G.; Back, D. F.; Zeni, G. (Biphenyl-2-alkyne) Derivatives as Common Precursors for the Synthesis of 9-Iodo-10-organochalcogen-phenanthrenes and 9-Organochalcogenphenanthrenes. Org. Biomol. Chem. 2016, 14, 10415-10426. (g) Zhou, Y.; Zhang, X.; Zhang, Y.; Ruan, L.; Zhang, J.; Zhang-Negrerie, D.; Du, Y. Iodocyclization of N-Arylpropynamides Mediated by Hypervalent Iodine Reagent: Divergent Synthesis of Iodinated Quinolin-2-ones and Spiro[4,5]trienones. Org. Lett. 2017, 19, 150-153. (11) (a) Gao, W. C.; Liu, T.; Zhang, B.; Li, X.; Wei, W. L.; Liu, Q.; Tian, J.; Chang, H. H. Synthesis of 3-Sulfenylated Coumarins: BF3·Et2O-Mediated Electrophilic Cyclization of Aryl Alkynoates Using N-Sulfanylsuccinimides. J. Org. Chem. 2016, 81,

11297-11304.

(b)

Zhang,

A.;

Zhang,

M.;

4-Aryl-3-arylthio-3,4-dihydroquinolin-2(1H)-ones

Ren, via

H.

Synthesis

Cyclization

of of

N-Arylcinnamamides with N-Thiosuccinimides. Synthesis 2018, 50, 575-582. (12) (a) Mantovani, A. C.; Goulart, T. A.; Back, D. F.; Menezes, P. H.; Zeni, G. Iron(III) Chloride and Diorganyl Diselenides-Mediated 6-endo-dig Cyclization of Arylpropiolates and Arylpropiolamides Leading to 3-Organoselenyl-2H-coumarins and 3-Organoselenyl-quinolinones. J. Org. Chem. 2014, 79, 10526-10536. (b) Recchi, A. M.; Back, D. F.; Zeni, G. Sequential Carbon-Carbon/Carbon-Selenium Bond Formation Mediated by Iron(III) Chloride and Diorganyl Diselenides: Synthesis and Reactivity of 2-Organoselenyl-Naphthalenes. J. Org. Chem 2017, 82, 2713-2723. (13) (a) Yang, W.; Yang, S.; Li, P.; Wang, L. Visible-light Initiated Oxidative 22


Page 23 of 25 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


Cyclization of Phenyl Propiolates with Sulfinic Acids to Coumarin Derivatives under Metal-free Conditions. Chem. Commun. 2015, 51, 7520-7523. (b) Zheng, D.; Yu, J.; Wu, J. Generation of Sulfonyl Radicals from Aryldiazonium Tetrafluoroborates and Sulfur Dioxide: The Synthesis of 3-Sulfonated Coumarins. Angew. Chem. Int. Ed. Ed. 2016, 55, 11925-11929. (c) Zhu, J.; Yang, W.-C.; Wang, X.-d.; Wu, L. PhotoredoxCatalysis in C-S Bond Construction: Recent Progress in Photo-Catalyzed Formation of Sulfones and Sulfoxides. Adv. Synth. Catal. 2018, 360, 386-400. (14)

(a)

Li,

Y.;

Lu,

Y.;

Qiu,

G.;

Ding,

Q.

Copper-Catalyzed

Direct

Trifluoromethylation of Propiolates: Construction of Trifluoromethylated Coumarins. Org. Lett. 2014, 16, 4240-4243. (b) Xu, J.; Wang, Y. L.; Gong, T. J.; Xiao, B.; Fu, Y. Copper-catalyzed endo-Type Trifluoromethylarylation of Alkynes. Chem. Commun. 2014, 50, 12915-12918. (c) Fu, W.; Zhu, M.; Zou, G.; Xu, C.; Wang, Z.; Ji, B. Visible-Light-Mediated Radical Aryldifluoroacetylation of Alkynes with Ethyl Bromodifluoroacetate for the Synthesis of 3-Difluoroacetylated Coumarins. J. Org. Chem. 2015, 80, 4766-4770. (d) Li, J.; Lei, Y.; Yu, Y.; Qin, C.; Fu, Y.; Li, H.; Wang, W. Co(OAc)2-Catalyzed

Trifluoromethylation

and

C(3)-Selective

Arylation

of

2‑(Propargylamino)pyridines via a 6-Endo-Dig Cyclization. Org. Lett. 2017, 19, 6052-6055. (15) Liu, W.; Chen, J.; Jin, R.; Xu, D.; Li, Y.; Ba, F.; Gu, G.; Kuang, Y.; Guo, H. CuBr2-Promoted Cyclization and Bromination of Arene–Alkynes: C–Br Bond Formation via Reductive Elimination of Cu(III) Species. Org. Chem. Front. 2016, 3, 852-855. 23



Page 24 of 25

(16) (a) Ng, Y. S.; Chan, C. S.; Chan, K. S. Free Porphyrin Catalyzed Direct C-H Arylation of Benzene with Aryl Halides. Tetrahedron Lett. 2012, 53, 3911-3914. (b) Zheng, X.; Yang, L.; Du, W.; Ding, A.; Guo, H. Amine-Catalyzed Direct Photoarylation of Unactivated Arenes. Chem. Asian. J. 2014, 9, 439-442. (17) (a) Wieczorek-Ciurowa, K.; Kozak, A. J. The Thermal Decomposition of Fe(NO3)3·9H2O. J. Therm. Anal. Cal. 1999, 58, 647-651. (b) Taniguchi, T.; Fujii, T.; Ishibashi, H. Iron-Mediated Radical Halo-Nitration of Alkenes. J. Org. Chem. 2010, 75,

8126-8132.

(c)

Taniguchi,

T.;

Ishibashi,

H.

Iron-Mediated

Radical

Nitro-Cyclization Reaction of 1,6-Dienes. Org. Lett. 2010, 12, 124-126. (18) (a) 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. (b) Zhu, N.; Zhao, J.; Bao, H. Iron Catalyzed Methylation and Ethylation of Vinyl Arenes. Chem. Sci. 2017, 8, 2081-2085. (c) Jian, W.; Ge, L.; Jiao, Y.; Qian, B.; Bao, H. Iron-Catalyzed DecarboxylativeAlkyl Etherification of Vinylarenes with Aliphatic Acids as the Alkyl Source. Angew. Chem. Int. Ed. 2017, 56, 3704-3708. (19) Jin, R.; Chen, Y.; Liu, W.; Xu, D.; Y, Li.; Ding, A.; Guo, H. Merging

photoredox catalysis with lewis acid catalysis: activation of carbon-carbon triple bond. Chem. Commun. 2016, 52, 9909-9912. (20) Pati, K.; Michas, C.; Allenger, D.; Piskun, I.; Coutros, P. S.; Gomes, G. P.; Alabugin, I. V. Synthesis of Functionalized Phenanthrenes via Regioselective Oxidative Radical Cyclization. J. Org. Chem. 2015, 80, 11706-11717. 24


Page 25 of 25 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


(21) Hua, H. -L.; He, Y. -T.; Qiu, Y. -F.; Li, Y.-X.; Song, B.; Gao, P.; Song, X. -R.; Guo, D. -H.; Liu, X.-Y.; Liang, Y. -M. Copper‐Catalyzed Difunctionalization of Activated Alkynes by Radical Oxidation-Tandem Cyclization/Dearomatization to Synthesize 3-Trifluoromethyl Spiro[4.5]trienones. Chem. Eur. J. 2015, 21, 1468-1473. (22) Liang, F.; Meike, N. Calcium‐Catalyzed Carboarylation of Alkynes. Chem. Eur. J. 2015, 21, 6367-6370.

25


Nitration and Cyclization of Arene-Alkynes: An ... - ACS Publications

Recommend Documents