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Construction of Vicinal All-Carbon Quaternary Stereocenters Enabled by a Catalytic Asymmetric Dearomatization Reaction of #-Naphthols with 3-Bromooxindoles Xihong Liu, Pengxin Wang, Lutao Bai, Dan Li, Linqing Wang, Dongxu Yang, and Rui Wang ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.8b03905 • Publication Date (Web): 22 Oct 2018 Downloaded from http://pubs.acs.org on October 22, 2018
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ACS Catalysis
Construction of Vicinal All-Carbon Quaternary Stereocenters Enabled by a Catalytic Asymmetric Dearomatization Reaction of βNaphthols with 3-Bromooxindoles Xihong Liu, Pengxin Wang, Lutao Bai, Dan Li, Linqing Wang,* Dongxu Yang, and Rui Wang* Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, China. KEYWORDS: asymmetric catalysis, dearomatization, vicinal all-carbon quaternary stereocenters, β-naphthols, 3,3’disubstituted oxindoles
ABSTRACT: The organocatalyzed asymmetric dearomative addition of phenols to indol-2-ones generated in situ from 3bromooxindoles was reported. This methodology leads to the efficient construction of a series of enantioenriched 3,3’disubstituted oxindoles bearing vicinal all-carbon quaternary stereocenters via a dearomatization process of phenols under mild reaction conditions. Besides, the representative large-scale reactions and related transformations of the dearomatized products reveal the potential synthetic utility of this protocol.
Vicinal all-carbon quaternary stereocenters, a structural arrangement found in a variety of natural products and biologically active compounds, have attracted tremendous interest from synthetic chemists.1 However, their asymmetric construction still represents a formidable challenge in organic synthesis due to the fact that C-C bond-forming reaction between the sterically congested, prochiral carbon species is inherently unfavourable. Despite impressive efforts have been made, only a limited number of catalytic asymmetric approaches, such as alkylation2 and cycloaddition reactions3, have been proved to be available for assembling of such structural motifs to date. Therefore, development of more novel and general synthetic methodologies towards such structural motifs in a catalytic asymmetric manner is urgently needed.
oxidative dearomatization reactions of phenols with nucleophiles,5,6 metal- and organocatalyzed non-oxidative dearomatization reactions by utilizing the nucleophilicity of the enol tautomer of phenols,7 as well as visible-lightpromoted dearomatization process have been developed.8 However, despite these elegant works, most of the cases enabled constructing the dearomative products with only one stereogenic center (Figure 1).5-9 It should be noted that only two examples documented the construction of continuous quaternary and tertiary stereocenters via an intermolucular dearomatization process of phenols. For examples, in 2012, Katsuki group reported an ironScheme 1. Catalytic asymmetric functionalization of 3-bromooxindoles with phenols
Recently, the catalytic asymmetric dearomatization reactions of phenols have emerged as one of the most efficient and straightforward approach for the construction of three-dimensional structures with readily available planar aromatic compounds as starting materials.4 And the corresponding methodologies, such as hypervalent-iodine- and transition-metal-mediated
Figure 1. Catalytic asymmetric dearomatization of βnaphthols.
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Table 1. Optimization of the reaction conditionsa
entry
Cat.
solvent
base
Time (h)
3a/4ab
3a Yield
(%)c
drb
erd
1
C1
THF
K2CO3
3
7.3:1
53
1.8:1
66.5:43.5
2
C2
THF
K2CO3
3
>20:1
79
9:1
92:8
3
C3
THF
K2CO3
4
7.5:1
55
2:1
72:28
4
C4
THF
K2CO3
3
>20:1
80
8.2:1
93.5:6.5
5
C5
THF
K2CO3
3
10.5:1
62
3.2:1
59.5:40.5
6
C6
THF
K2CO3
3
6:1
52
2:1
50:50
7
C7
THF
K2CO3
3
14:1
70
4:1
18:82
8
C4
CH2Cl2
K2CO3
3
>20:1
85
17:1
93:7
9
C4
Toluene
K2CO3
24
>20:1
82
12.5:1
93.5:6.5
10
C4
MTBE
K2CO3
6
>20:1
92
>20:1
96:4
11
C4
Et2O
K2CO3
7
>20:1
90
>20:1
96:4
12
C4
MTBE
Na2CO3
24
>20:1
88
>20:1
95.5:4.5
13
C4
MTBE
Cs2CO3
24
15:1
79
11:1
94.5:5.5
14
C4
MTBE
K3PO4
10
>20:1
74
6.8:1
86:14
15
C4
MTBE
DIPEA
13
>20:1
75
12.8:1
95:5
16e
C4
MTBE
K2CO3
10
>20:1
91
>20:1
96:4
17e,f
C4
MTBE
K2CO3
10
>20:1
91
>20:1
97:3
aReaction
conditions: 1a (0.075 mmol, 1.5 equiv), 2a (0.05 mmol, 1.0 equiv), Cat. (0.01 mmol) and base (0.1 mmol, 2.0 equiv) in 0.3 mL of solvent. bDetermined by 1H NMR analysis of the crude mixture. cIsolated yield of the major diastereomer. dDetermined by HPLC using a chiral stationary phase. eWith 1.2 equiv of K2CO3 and 1.2 equiv of 1a. fCarried out on 0.1 mmol scale in 0.6 mL of MTBE.
catalyzed asymmetric oxidative dearomatization of βnaphthols utilizing nitroalkanes as nucleophiles.10b And then, our group developed a deriect enantioselective dearomatization of β-naphthols with aziridines by employing a in situ generated magnesium catalyst under non-oxidative conditions.10c However, as for the construction of continuous quaternary stereocenters, no successful example was reported thus far, mainly due to the fact that it is indeed difficult to overcome the high energy barrier caused by loss of aromaticity and also the steric congestion between carbon substituents simultaneously. In order to develop and explore more efficient and reliable dearomatization protocols towards structurally complex molecules, herein, we describe the first efficient assembly of vicinal all-carbon quaternary stereocenters via a catalytic asymmetric dearomatization reaction of β-
naphthols with 3-bromooxindoles, providing a novel and efficient protocol toward 3,3’-disubstituted oxindoles bearing vicinal all-carbon quaternary stereocenters (Scheme 1b). To the best of our knowledge, such structural motifs are ubiquitous not only in natural products and pharmaceutical compounds11, but also in key intermediates for the synthesis of indole alkaloids.12 In our previous work, we realized the asymmetric construction of vicinal all-carbon quaternary stereocenters via an alkylation reaction of 3bromooxindoles with 3-substituted indols catalyzed by a nickel(II)-diamine complex.13 To futher extend the application of dearomatization reactions in the construction of sterically restricted vicinal all-carbon quaternary stereocenters, we envisioned that indol-2ones14 generated in situ from 3-bromooxindoles could also
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ACS Catalysis be captured by 1,3-disubstituted 2-naphthols. Owing to the nucleophilic property and relatively small steric hindrance of phenol oxygen, O-alkylation products is likely to be produced (Scheme 1a).15 Therefore, finding a competent catalytic system to control the site selectivity and stereoselectivity seems to be a critical task. Considering the significant advantages of bifunctional organocatalyts in asymmetric transformations, we assume that H-bond donor organocatalysts could also be applied to control the stereochemistry of the dearomative alkylation of 3-bromooxindoles. Accordingly, our initial investigation was launched with a model reaction of 1,3dimethyl-2-naphthol (1a) and 3-benzyl-3-bromooxindole (2a) in the presence of 2.0 equiv of K2CO3 and 20 mol% of typical Takemoto thiourea (C1, Table 1). As expected, the indol-2-ones generated in situ from 2a was successfully captured by 1a and led to moderate C/O addition ratios Table 2. The substrate scope with respect to 3substituted 3-bromo-2-oxindolesa
a
Reaction conditions: 0.12 mmol 1a, 0.10 mmol 2, 0.12 mmol K2CO3 and 20 mol% C4 in MTBE (0.6 mL). Isolated yields. The d.r. values were determined by 1H NMR analysis of the crude mixture. The e.r. values were determined by HPLC analysis using a chiral stationary phase.
(7.3:1), albeit poor dr and er values for 3a (entry 1). Encouraged by this result, cinchona alkaloid derived thioureas (C3 and C6) and squaramide C5 were further evaluated (entries 2-7). However, none of them led to a much better outcome. Based on some relevant works,14c,d we speculated that urea catalysts with decreased acidity of the N-H bonds might be conductive to the improvement of the stereocontrol. To our delight, the use of either C2 or C4 dramatically improved both the C/O addition ratios and stereoselectivities. With C4 as the optimal catalyst, the solvents were screened and MTBE was identified to be the most suitable choice concerning both diastereo- and enantioselectivities (entries 8-11). Next, various bases, including Na2CO3, Cs2CO3, K3PO4 and DIPEA were evaluated (entries 12-15). However, none of them afforded a better result than that of K2CO3. It should be noted that Table 3. The substrate scope with respect to βnaphtholsa
aReaction
conditions: 0.12 mmol 1, 0.10 mmol 2a, 0.12 mmol K2CO3 and 20 mol% C4 in MTBE (0.6 mL). Isolated yields. The d.r. values were determined by 1H NMR analysis of the crude mixture. The e.r. values were determined by HPLC analysis using a chiral stationary phase.
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lowering the amounts of both 1,3-dimethyl-2-naphthol (1a) and K2CO3 to 1.2 equiv, the same excellent outcome was obtained (entry 16, 3a:4a>20:1, >20:1 dr and 96:4 er). Having established the optimal reaction conditions, we firstly investigated the substrate scope with respect to 3substituted 3-bromo-2-oxindoles. As shown in table 2, 3benzyl-substituted-3-bromooxindoles, with either electron-donating or electron-withdrawing substituents in the meta- and para-position of the phenyl ring of R1, were all well tolerated, and gave the corresponding dearoma tized products in high yields and stereoselectivities (3b3f). Besides, oxindoles 2 bearing a bulkier naphthalene or heteroaryl group also worked well (3g-3i). It is particularly worth noting that various alkyl chains, such as cyclohexyl methyl, allyl, azidoethyl, among others, were all compatible substituents on the C3 position of 2. In general, different alkyl chains substituted dearomatized adducts were all obtained with satisfactory yields and high stereoselectivities (3j-3q). Only in the case of 3r was a relatively lower ee value delivered. Additionally, substitutions of the phenyl ring of oxindole core with methyl or halogen at different positions also afforded the desired products with excellent selectivities (3s-3v). Subsequently, we further explored the generality of this dearomatization process by involving various different substituted 2-naphthols (Table 3).16 The substitutions of 3-position of 2-naphthols with alkyl or aromatic groups led to the dearomatized products with excellent yield and stereoselectivities (3y-3ac). 2-naphthols 1b and 1c, containing a Cl and Br group at its 3-position respectively, also proceeded smoothly and gave the corresponding products in high yields, but with reduced enantioselectivities. Gratifyingly, 2-naphthols with bulkier groups, such as pentyl and heptyl at the C1 position, also underwent the current protocol (3af-3ag). It should be noted that a slight compromise of enantioselectivities resulted from a halogen substitution at the C3 position of 2-naphthols was also observed in the cases of 3ae and 3ag. Then, 2naphthol 5 bearing no substituent at its 3-position was also employed, affording the dearomatized product 3ah in only 36% yield with poor stereoselectivity (6.5:1 dr, 64.5:35.5 er) and C/O addition ratio (1:1). Which indicates that the substitution of 3-position of 2-naphthols is essential for providing either good stereoselectivities or C/O addition ratios.
Furthermore, 3-chlorooxindole 6 was also synthesized to further extend the substrate scope (Scheme 2). However, compared with 3-bromooxindole 2a, compound 6 provided a relatively lower stereoselectivity (10:1 dr and 88.5:11.5 er). The absolute stereochemistry of the dearomatized products 3 was determined by X-ray crystallographic analysis of 3i.17 Scheme 3. Control experiments
To gain insight into the mechanism of this dearomatization process, some control experiments were conducted (Scheme 3). N-methyl-protected 3-bromooxindole 9 failed to give any product, which highlights the generation of putative o-azaxylylene intermediate A in situ (Scheme 3a). With potassium 2-naphtholate 10 as the substrate, the dearomatized product 3a was obtained with only 1.3:1 dr and 56.5:43.5 er vaue, suggesting that the deprotonation process of 2-naphthol in the current protocol is not caused by K2CO3 (Scheme 3b). Based on this experiment results and previous studies,14 a catalytic model was proposed to explain the observed stereochemical preference (Figure 2). Firstly, a reactive intermediate indol-2-one was generated in situ from precursor 2a in the presence of base. Subsequently, under the catalysis of bifunctional catalyst C4, β-naphthol 1a and indol-2-one were activated by the tertiary amine moiety and the two urea hydrogen atoms through weak hydrogen bonds, respectively. Thus the Re face of indol-2-one was attacked by the Re face of β-naphthol to afford the corresponding product 3a. Besides, two peaks at m/z 800.3029 and m/z 972.3934 in the ESI-MS spectrum of the reaction mixture, further support
Scheme 2. Further investigation of substrate scope
Figure 2. Plausible reaction pathway.
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ACS Catalysis further transformed into 1,5-amino alcohol 13 when treated with PPh3. In summary, we have developed an organocatalyzed asymmetric dearomatization reaction of β-naphthols with 3-bromooxindoles under mild reaction conditions. By which a series of 3,3’-disubstituted oxindoles bearing vicinal all-carbon quaternary stereocenters were obtained in good to excellent yields and stereoselectivities. This protocol, to the best of our knowledge, is the first example of constructing vicinal all-carbon quaternary stereocenters via a dearomatization process of β-naphthols.
ASSOCIATED CONTENT Supporting Information. This material is available free of charge via the Internet at http://pubs.acs.org. X-ray data of 3i (CIF) Experimental details, characterization data for all of the new compounds, and copies of NMR and HPLC spectra (PDF) Figure 3. ESI-MS studies.
AUTHOR INFORMATION
Scheme 4. Gram-scale preparation of 3a and representative transformations of dearomatized product 3q
Corresponding Author * E-mail:
[email protected] * E-mail:
[email protected] ORCID
Rui Wang: 0000-0002-4719-9921 Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT We are grateful for the financial support from the NSFC (21432003, 81473095, 21602091), the Program for Chang-jiang Scholars and Innovative Research Team in University (PCSIRT: No. IRT_15R27), and the Fundamental Research Funds for the Central Universities (lzujbky-2017-k11, lzujbky2017-19 and lzujbky-2017-118).
REFERENCES
the proposed reactive intermediate and transition state (Figure 3). To demonstrate the synthetic utility of this dearomatization process, a gram-scale reaction of 1a and 2a was conducted (Scheme 4). To our delight, the reaction proceeded smoothly to afford the corresponding product 3a without significant erosion of diastereoselectivity, enantioselectivity and yield. Furthermore, some representative transformations of the dearomatized product 3q were exhibited. For example, a click reaction of 3q with phenylacetylene easily occurred in the presence of CuI and Et3N at room temperature. In addition, subjecting 3q to a reductive reaction using NaBH4 in methanol led to 12 in 87% yield, which could be
(1) For selected reviews on the asymmetric construction of vicinal all-carbon quaternary stereocenters, see: (a) Peterson, E. A.; Overman, L. E. Contiguous Stereogenic Quaternary Carbons: A Daunting Challenge in Natural Products Synthesis. Proc. Natl. Acad. Sci. USA 2004, 101, 11943-11948. (b) Long, R.; Huang, J.; Gong, J.; Yang, Z. Direct Construction of Vicinal All-Carbon Quaternary Stereocenters in Natural Product Synthesis. Nat. Prod. Rep. 2015, 32, 1584-1601. (c) Liang, K.; Xia, C. Recent Advances of Transition Metal-Mediated Oxidative Radical Reactions in Total Synthesis of Indole Alkaloids. Chin. J. Chem. 2017, 35, 255-270. For selected examples on the total synthesis, see: (d) Corey, E. J.; Lin, S. A Short Enantioselective Total Synthesis of Dammarenediol II. J. Am. Chem. Soc. 1996, 118, 8765-8766. (e) Lemieux, R. M.; Meyers, A. I. Asymmetric Synthesis of (-)Trichodiene. Generation of Vicinal Stereogenic Quaternary Centers via the Thio-Claisen Rearrangement. J. Am. Chem. Soc. 1998, 120, 5453-5457. (f) Overman, L. E.; Paone, D. V.; Stearns, B. A. Direct Stereo- and Enantiocontrolled Synthesis of Vicinal Stereogenic Quaternary Carbon Centers. Total Syntheses of mesoand (-)-Chimonanthine and (+)-Calycanthine. J. Am. Chem. Soc. 1999, 121, 7702-7703. (g) Overman, L. E.; Paone, D. V. Enantioselective Total Syntheses of Ditryptophenaline and ent-WIN 64821. J. Am. Chem. Soc. 2001, 123, 9465-9467. (h) Movassaghi, M.;
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Schmidt, M. A. Concise Total Synthesis of (-)-Calycanthine, (+)Chimonanthine, and (+)-Folicanthine. Angew. Chem. Int. Ed. 2007, 46, 3725-3728. (i) Movassaghi, M.; Schmidt M. A.; Ashenhurst, J. A. Concise Total Synthesis of (+)-WIN 64821 and (-)Ditryptophenaline. Angew. Chem. Int. Ed. 2008, 47, 1485-1487. (j) Kim, J.; Ashenhurst, J. A.; Movassaghi, M. Total Synthesis of (+)11,11'-Dideoxyverticillin A. Science 2009, 324, 238-241. (k) Kim, J.; Movassaghi, M. General Approach to Epipolythiodiketopiperazine Alkaloids: Total Synthesis of (+)-Chaetocins A and C and (+)-12,12'-Dideoxychetracin A. J. Am. Chem. Soc. 2010, 132, 1437614378. (l) Shimizu, Y.; Shi, S.-L.; Usuda, H.; Kanai, M.; Shibasaki, M. Catalytic Asymmetric Total Synthesis of ent-Hyperforin. Angew. Chem. Int. Ed. 2010, 49, 1103-1106. (m) Trost, B. M.; Osipov, M. Palladium-Catalyzed Asymmetric Construction of Vicinal AllCarbon Quaternary Stereocenters and its Application to the Synthesis of Cyclotryptamine Alkaloids. Angew. Chem. Int. Ed. 2013, 52, 9176-9181. (2) (a) Uyeda, C.; Rötheli, A. R.; Jacobsen, E. N. Catalytic Enantioselective Claisen Rearrangements of O-Allyl β-Ketoesters. Angew. Chem. Int. Ed. 2010, 49, 9753-9756. (b) Mitsunuma, H.; Shibasaki, M.; Kanai, M.; Matsunaga, S. Catalytic Asymmetric Total Synthesis of Chimonanthine, Folicanthine, and Calycanthine through Double Michael Reaction of Bisoxindole. Angew. Chem. Int. Ed. 2012, 51, 5217-5221. (c) Trost, B. M.; Osipov, M. Palladium-Catalyzed Asymmetric Construction of Vicinal AllCarbon Quaternary Stereocenters and its Application to the Synthesis of Cyclotryptamine Alkaloids. Angew. Chem. Int. Ed. 2013, 52, 9176-9181. (d) Ohmatsu, K., Ando, Y.; Ooi, T. Asymmetric Substitution at the Tetrasubstituted Chiral Carbon: Catalytic Ring-Opening Alkylation of Racemic 2,2-Disubstituted Aziridines with 3‑Substituted Oxindoles. J. Am. Chem. Soc. 2013, 135, 18706-18709. (e) Ghosh, S.; Bhunia, S.; Kakde, B. N.; De, S.; Bisai, A. Enantioselective Construction of Vicinal All-Carbon Quaternary Centers via Catalytic Double Asymmetric Decarboxylative Allylation. Chem. Commun. 2014, 50, 2434-2437. (f) Yang, H.; Cao, K.-S.; Zheng, W.-H. A Catalytic Enantioselective Approach to Tetrol Bearing Vicinal All-Carbon Quaternary Stereogenic Centers. Chem. Commun. 2017, 53, 3737-3740. (3) (a) Trost, B. M.; Cramer, N.; Silverman, S. M. Enantioselective Construction of Spirocyclic Oxindolic Cyclopentanes by Palladium-Catalyzed Trimethylenemethane-[3+2]-Cycloaddition. J. Am. Chem. Soc. 2007, 129, 12396-12397. (b) Payette, J. N.; Yamamoto, H. Regioselective and Asymmetric Diels-Alder Reaction of 1- and 2-Substituted Cyclopentadienes Catalyzed by a Brønsted Acid Activated Chiral Oxazaborolidine. J. Am. Chem. Soc. 2007, 129, 9536-9537. (c) Gao, L.; Hwang, G.-S.; Ryu, D. H. Oxazaborolidinium Ion-Catalyzed Cyclopropanation of αSubstituted Acroleins: Enantioselective Synthesis of Cyclopropanes Bearing Two Chiral Quaternary Centers. J. Am. Chem. Soc. 2011, 133, 20708-20711. (d) Noole, A.; Sucman, N. S.; Kabeshov, M. A.; Kanger, T.; Macaev, F. Z.; Malkov, A. V. Highly Enantio- and Diastereoselective Generation of Two Quaternary Centers in Spirocyclopropanation of Oxindole Derivatives. Chem. Eur. J. 2012, 18, 14929-14933. (e) Cao, Z.-Y.; Wang, X.; Tan, C.; Zhao, X.L.; Zhou, J.; Ding, K. Highly Stereoselective Olefin Cyclopropanation of Diazooxindoles Catalyzed by a C2‑Symmetric Spiroketal Bisphosphine/Au(I) Complex. J. Am. Chem. Soc. 2013, 135, 81978200. (f) Ohmatsu, K.; Imagawa N.; Ooi, T. Ligand-Enabled Multiple Absolute Stereocontrol in Metal-Catalysed Cycloaddition for Construction of Contiguous All-Carbon Quaternary Stereocentres. Nat. Chem. 2014, 6, 47-51. (g) Jolit, A.; Walleser, P. M.; Yap, G. P. A.; Tius, M. A. Catalytic Enantioselective Nazarov Cyclization: Construction of Vicinal All-Carbon-Atom Quaternary Stereocenters. Angew. Chem. Int. Ed. 2014, 53, 6180-6183. (4) For selected reviews, see: (a) Ortiz, F. L.; Iglesias, M. J.; Fernández, I.; Andújar Sánchez C. M.; Ruiz Gόmez, G. Nucleo-
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philic Dearomatizing (DNAr) Reactions of Aromatic C,H-Systems. A Mature Paradigm in Organic Synthesis. Chem. Rev. 2007, 107, 1580-1691. (b) Roche, S. P.; Porco, Jr., J. A. Dearomatization Strategies in the Synthesis of Complex Natural Products. Angew. Chem. Int. Ed. 2011, 50, 4068-4093. (c) Zhuo, C.-X.; Zhang, W.; You, S.-L. Catalytic Asymmetric Dearomatization Reactions. Angew. Chem. Int. Ed. 2012, 51, 12662-12686. (d) Zhuo, C.-X.; Zheng, C.; You, S.-L. Transition-Metal-Catalyzed Asymmetric Allylic Dearomatization Reactions. Acc. Chem. Res. 2014, 47, 2558-2573. (e) Wu, W.-T.; Zhang, L.; You, S.-L. Catalytic Asymmetric Dearomatization (CADA) Reactions of Phenol and Aniline Derivatives. Chem. Soc. Rev. 2016, 45, 1570-1580. (f) Liang, X.-W.; Zheng, C.; You, S.-L. Dearomatization through Halofunctionalization Reactions. Chem. Eur. J. 2016, 22, 11918-11933. (g) Sun, W.; Li, G.; Hong, L.; Wang, R. Asymmetric Dearomatization of Phenols. Org. Biomol. Chem. 2016, 14, 2164-2176. For halogenative dearomatization reactions, see: (h) Phipps, R. J.; Toste, F. D. Chiral Anion Phase-Transfer Catalysis Applied to the Direct Enantioselective Fluorinative Dearomatization of Phenols. J. Am. Chem. Soc. 2013, 135, 1268-1271. (i) Yin, Q.; Wang, S.-G.; Liang, X.W.; Gao, D.-W.; Zheng, J.; You, S.-L. Organocatalytic Asymmetric ChlorinativeDearomatization of Naphthols. Chem. Sci. 2015, 6, 4179-4183. (5) For hypervalent iodine mediated oxidative dearomatization of phenols and naphthols, see: (a) Dohi, T.; Maruyama, A.; Takenaga, N.; Senami, K.; Minamitsuji, Y.; Fujioka, H.; Caemmerer S. B.; Kita, Y. A Chiral Hypervalent Iodine(III) Reagent for Enantioselective Dearomatization of Phenols. Angew. Chem. Int. Ed. 2008, 47, 3787-3790. (b) Uyanik, M.; Yasui, T.; Ishihara, K. Enantioselective Kita Oxidative Spirolactonization Catalyzed by In Situ Generated Chiral Hypervalent Iodine(III) Species. Angew. Chem. Int. Ed. 2010, 49, 2175-2177. (c) Dohi, T.; Takenaga, N.; Nakae, T.; Toyoda, Y.; Yamasaki, M.; Shiro, M.; Fujioka, H.; Maruyama, A.; Kita, Y. Asymmetric Dearomatizing Spirolactonization of Naphthols Catalyzed by SpirobiindaneBased Chiral Hypervalent Iodine Species. J. Am. Chem. Soc. 2013, 135, 4558-4566. (d) Uyanik, M.; Yasui T.; Ishihara, K. Hydrogen Bonding and Alcohol Effects in Asymmetric Hypervalent Iodine Catalysis: Enantioselective Oxidative Dearomatization of Phenols. Angew. Chem. Int. Ed. 2013, 52, 9215-9218. (6) For transition metal mediated oxidative dearomatization reactions, see: (a) Dong, S.; Zhu, J.; Porco, Jr., J. A. Enantioselective Synthesis of Bicyclo[2.2.2]octenones Using a CopperMediated Oxidative Dearomatization/[4+2] Dimerization Cascade. J. Am. Chem. Soc. 2008, 130, 2738-2739. (b) Zhu, J.; Grigoriadis, N. P.; Lee, J. P.; Porco, Jr., J. A. Synthesis of the Azaphilones Using Copper-Mediated Enantioselective Oxidative Dearomatization. J. Am. Chem. Soc. 2005, 127, 9342-9343. (7) For selected recent dearomatization reactions of phenols and naphthols under non-oxidative conditions, see: (a) Zhuo, C.X.; You, S.-L. Palladium-Catalyzed Intermolecular Asymmetric Allylic Dearomatization Reaction of Naphthol Derivatives. Angew. Chem. Int. Ed. 2013, 52, 10056-10059. (b) Wang, S.-G.; Liu, X.-J.; Zhao, Q.-C.; Zheng, C.; Wang S.-B.; You, S.-L. Asymmetric Dearomatization of β-Naphthols through a BifunctionalThiourea-Catalyzed Michael Reaction. Angew. Chem. Int. Ed. 2015, 54, 14929-14932. (c) Zheng, J.; Wang, S.-B.; Zheng, C.; You, S.-L. Asymmetric Dearomatization of Naphthols via a RhCatalyzed C(sp2)−H Functionalization/Annulation Reaction. J. Am. Chem. Soc. 2015, 137, 4880-4883. (d) Yang, L.; Zheng, H.; Luo, L.; Nan, J.; Liu, J.; Wang Y.; Luan, X. Palladium-Catalyzed Dynamic Kinetic Asymmetric Transformation of Racemic Biaryls: Axial-to-Central Chirality Transfer. J. Am. Chem. Soc. 2015, 137, 4876-4879. (e) Wang, S.-G.; Yin, Q.; Zhuo, C.-X.; You, S.-L. Asymmetric Dearomatization of β-Naphthols through an Amination Reaction Catalyzed by a Chiral Phosphoric Acid. Angew. Chem. Int. Ed. 2015, 54, 647-650. (f) Nan, J.; Liu, J.; Zheng, H.;
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ACS Catalysis Zuo, Z.; Hou, L.; Hu, H.; Wang, Y.; Luan, X. Direct Asymmetric Dearomatization of 2-Naphthols by Scandium-Catalyzed Electrophilic Amination. Angew. Chem. Int. Ed. 2015, 54, 2356-2360. (g) Du, K.; Guo, P.; Chen, Y.; Cao, Z.; Wang, Z.; Tang, W. Enantioselective Palladium-Catalyzed Dearomative Cyclization for the Efficient Synthesis of Terpenes and Steroids. Angew. Chem. Int. Ed. 2015, 54, 3033-3037. (h) Tu, H.-F.; Zheng, C.; Xu, R.-Q.; Liu, X.-J.; You, S.-L. Iridium-Catalyzed Intermolecular Asymmetric Dearomatization of β-Naphthols with Allyl Alcohols or Allyl Ethers. Angew. Chem. Int. Ed. 2017, 56, 3237-3241. (i) Shen, D.; Chen, Q.; Yan, P.; Zeng, X.; Zhong, G. Enantioselective Dearomatization of Naphthol Derivatives with Allylic Alcohols by Cooperative Iridium and Brønsted Acid Catalysis. Angew. Chem. Int. Ed. 2017, 56, 3242-3246. (j) Zhang, Y.; Liao, Y.; Liu, X.; Xu, X.; Lin L.; Feng, X. Catalytic Asymmetric Hydroxylative Dearomatization of 2-Naphthols: Synthesis of Lacinilene Derivatives. Chem. Sci. 2017, 8, 6645-6649. (k) Nakayama, H.; Harada, S.; Kono, M.; Nemoto, T. Chemoselective Asymmetric Intramolecular Dearomatization of Phenols with α-Diazoacetamides Catalyzed by Silver Phosphate. J. Am. Chem. Soc. 2017, 139, 10188-10191. (8) (a) Guo, Q.; Wang, M.; Liu, H.; Wang, R.; Xu, Z. VisibleLight-Promoted Dearomative Fluoroalkylation of β-Naphthols through Intermolecular Charge Transfer. Angew. Chem. Int. Ed. 2018, 57, 4747-4751. (b) Cheng, Y.-Z.; Zhou, K.; Zhu, M.; Li, L.-A.C.; Zhang, X.; You, S.-L. Visible-Light Promoted Intermolecular Oxidative Dearomatization of β-Naphthols with NHydroxycarbamates. Chem. Eur. J. 2018, 24, 12519. (9) For our previous works on dearomatization reactions, see: (a) Yang, D.; Wang, L.; Kai, M.; Li, D.; Yao, X.; Wang, R. Applicationofa C-C Bond-Forming Conjugate Addition Reaction in Asymmetric Dearomatization of β-Naphthols. Angew. Chem. Int. Ed. 2015, 54, 9523-9527. (b) Wang, L.; Yang, D.; Li, D.; Wang, P.; Wang, K.; Wang, J.; Jiang, X.; Wang, R. MgII-Mediated Catalytic Asymmetric Dearomatization (CADA) Reaction of β-Naphthols with Dialkyl Acetylenedicarboxylates. Chem. Eur. J. 2016, 22, 8483-8487. (c) Zhu, G.; Bao, G.; Li, Y.; Yang, J.; Sun, W.; Li, J.; Hong, L.; Wang, R. Chiral Phosphoric Acid Catalyzed Asymmetric Oxidative Dearomatization of Naphthols with Quinones. Org. Lett. 2016, 18, 5288-5291. (d) Liu, X.; Yang, D.; Wang, K.; Zhang, J.; Wang, R. A Catalyst-Free 1,3-Dipolar Cycloaddition of C,N-Cyclic Azomethine Imines and 3Nitroindoles: an Easy Access to Five-Ring-Fused Tetrahydroisoquinolines. Green Chem. 2017, 19, 82-87. (e) Zhu, G.; Li, Y.; Bao, G.; Sun, W.; Huang, L.; Hong, L.; Wang, R. Catalytic Kinetic Resolution of Spiro-Epoxyoxindoles with 1‑Naphthols: Switchable Asymmetric Tandem Dearomatization/Oxa-Michael Reaction and Friedel−Crafts Alkylation of 1‑Naphthols at the C4 Position. ACS Catal. 2018, 8, 1810-1816. (10) (a) Rudolph, A.; Bos, P. H.; Meetsma, A.; Minnaard, A. J.; Feringa, B. L. Catalytic Asymmetric Conjugate Addition/Oxidative Dearomatization Towards Multifunctional Spirocyclic Compounds. Angew. Chem. Int. Ed. 2011, 50, 5834-5838. (b) Oguma, T.; Katsuki, T. Iron-Catalyzed Dioxygen-Driven C−C Bond Formation: Oxidative Dearomatization of 2‑Naphthols with Construction of a Chiral Quaternary Stereocenter. J. Am. Chem. Soc. 2012, 134, 20017-20020. (c) Yang, D.; Wang, L.; Han, F.; Li, D.; Zhao D.; Wang, R. Intermolecular Enantioselective Dearomatization Reaction of β-Naphthol Using meso-Aziridine: A Bifunctional In Situ Generated Magnesium Catalyst. Angew. Chem. Int. Ed. 2015, 54, 2185-2189. (d) Cheng, Q.; Wang, Y.; You, S.-L. Chemo-, Diastereo-, and Enantioselective IridiumCatalyzed Allylic Intramolecular Dearomatization Reaction of Naphthol Derivatives. Angew. Chem. Int. Ed. 2016, 55, 3496-3499. (11) (a) Kushida, N.; Watanabe, N.; Okuda, T.; Yokoyama, F.; Gyobu, Y.; Yaguchi, T. PF1270A, B and C, Novel Histamine H3 Receptor Ligands Produced by Penicillium waksmanii PF1270. J.
Antibiot. 2007, 60, 667-673. (b) Mercado-Marin, E. V.; GarciaReynaga, P.; Romminger, S.; Pimenta, E. F.; Romney, D. K.; Lodewyk, M. W.; Williams, D. E.; Andersen, R. J.; Miller, S. J.; Tantillo, D. J.; Berlinck, R. G. S.; Sarpong, R. Total Synthesis and Isolation of Citrinalin and Cyclopiamine Congeners. Nature 2014, 509, 318-324. (12) (a) Steven, A.; Overman, L. E. Total Synthesis of Complex Cyclotryptamine Alkaloids: Stereocontrolled Construction of Quaternary Carbon Stereocenters. Angew. Chem. Int. Ed. 2007, 46, 5488-5508. (b) Ruiz-Sanchis, P.; Savina, S. A.; Albericio, F.; Á lvarez, M. Structure, Bioactivity and Synthesis of Natural Products with Hexahydropyrrolo[2,3-b]indole. Chem. Eur. J. 2011, 17, 1388-1408. (13) Zhang, H.; Hong, L.; Kang, H.; Wang, R. Construction of Vicinal All-Carbon Quaternary Stereocenters by Catalytic Asymmetric Alkylation Reaction of 3‑Bromooxindoles with 3‑Substituted Indoles: Total Synthesis of (+)-Perophoramidine. J. Am. Chem. Soc. 2013, 135, 14098-14101. (14) For selected examples, see: (a) Ma, S.; Han, X.; Krishnan, S.; Virgil, S. C.; Stoltz, B. M. Catalytic Enantioselective Stereoablative Alkylation of 3-Halooxindoles: Facile Access to Oxindoles with C3 All-Carbon Quaternary Stereocenters. Angew. Chem. Int. Ed. 2009, 48, 8037-8041. (b) Zuo, J.; Liao, Y.-H.; Zhang, X.-M.; Yuan, W.-C. Organocatalyzed Enantioselective Decarboxylative Stereoablation Reaction for the Construction of 3,3’Disubstituted Oxindoles Using β‑Ketoacids and 3‑Halooxindoles. J. Org. Chem. 2012, 77, 11325-11332. (c) Wu, C.; Li, G.; Sun, W.; Zhang, M.; Hong, L.; Wang, R. Organocatalytic Highly Enantioselective Monofluoroalkylation of 3-Bromooxindoles: Construction of Fluorinated 3,3’-Disubstituted Oxindoles and Their Derivatives. Org. Lett. 2014, 16, 1960-1963. (d) Bai, X.; Jing, Z.; Liu, Q.; Ye, X.; Zhang, G.; Zhao, X.; Jiang, Z. L‑Amino Acid Based Urea-Tertiary Amine-Catalyzed Chemoselective and Asymmetric Stereoablative Carboxylation of 3‑Bromooxindoles with Malonic Acid Half Thioesters. J. Org. Chem. 2015, 80, 12686-12696. (e) Han, S.-J.; Vogt, F.; May, J. A.; Krishnan, S.; Gatti, M.; Virgil, S. C.; Stoltz, B. M. Evolution of a Unified, Stereodivergent Approach to the Synthesis of Communesin F and Perophoramidine. J. Org. Chem. 2015, 80, 528-547. (f) Zheng, J.; Lin, L.; Dai, L.; Tang, Q.; Liu, X.; Feng, X. Nickel-Catalyzed Conjugate Addition of Silyl Ketene Imines to In Situ Generated Indol-2-ones: Highly Enantioseletive Construction of Vicinal All-Carbon Quaternary Stereocenters. Angew. Chem. Int. Ed. 2017, 56, 13107-13111. (15) For an example of aryloxylation of 3-bromoxindoles with phenols, see: Jadhav, A. P.; Manchanda, A.; Jaiswal, M. K.; Singh, R. P. Asymmetric Stereoablative Aryloxylation of 3Bromooxindoles with Bifunctional Catalyst. Adv. Synth. Catal. 2017, 359, 3917-3921. (16) Besides 2-naphthols, phenol 7 also underwent the current protocol, providing the corresponding dearomatized product 8 in 68% yield, but with
