Letter Cite This: Org. Lett. XXXX, XXX, XXX−XXX
pubs.acs.org/OrgLett
Catalytic Regio- and Enantioselective Oxytrifluoromethylthiolation of Aliphatic Internal Alkenes by Neighboring Group Assistance Jia Xu,† Yuanyuan Zhang,† Tian Qin, and Xiaodan Zhao* Institute of Organic Chemistry & MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China
Downloaded via KAOHSIUNG MEDICAL UNIV on September 29, 2018 at 00:35:46 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
S Supporting Information *
ABSTRACT: Chiral selenide-catalyzed oxytrifluoromethylthiolation of aliphatic internal alkenes by a formally intermolecular strategy is disclosed, affording CF3S 1,3amino alcohol and 1,3-diol derivatives with high regio-, enantio-, and diastereoselectivities. The reactions are promoted by a neighboring imide or ester group on substrates via a six-membered ring transition state. This assistance strategy is also successfully applied to the regio- and diastereoselective oxyhalofunctionalization of internal alkenes and the conversion of alkynes.
A
is tethered to the double bond of internal alkenes, the marginal difference of electron density at the two carbons of the double bond can result in the highly regioselective addition. The other is a directing group controlled strategy.6 A directing group is installed on substrates to chelate metal catalyst or organocatalyst to control the regioselectivity. In addition, this directing fashion heavily benefits the enantioselectivity. Despite these impressive achievements, the types of functional groups selectively incorporated into the double bond of internal alkenes are still limited. Thus, developing new methods toward highly regio- and enantioselective introduction of two different functional groups into internal alkenes to synthesize valuable molecules is highly desirable. 1,3-Amino alcohols and 1,3-diols are important synthetic intermediates, and their structural units widely exist in natural products and bioactive compounds.7,8 As a result, an elegant metal-free or metal-catalyzed route via directed hydrofunctionalization of internal alkenes has been developed to construct 1,3-amino alcohols and protected 1,3-diols.6a−d,i In this transformation, internal alkenes containing nitrogen or oxygen substituents in the homoallylic position as a directing group underwent highly regio- and enantioselective hydroboration and then oxidation to afford the final products. Inspired by these results, we questioned whether homoallylic amides and esters could form the corresponding 1,3-amino alcohols and acyl-protected 1,3-diols in one step, respectively. Because introduction of the trifluoromethylthio (CF3S) group into parent molecules can change their physical and chemical properties as well as bioactivities,9,10 we proposed a catalytic, formally intermolecular, electrophilic difunctionalization of aliphatic internal alkenes to construct chiral CF3S 1,3-amino
lkene difunctionalization is a fundamental organic reaction and provides a facile pathway for quick construction of functionalized molecules.1−4 However, highly regio- and enantioselective difunctionalization of internal alkenes, especially those that are aliphatic, remains a challenge. To achieve satisfactory results in this difunctionalization, regioselectivity is the first issue to be considered. In the previous work, two strategies are generally utilized to gain high regioselectivity (Scheme 1a).5,6 One strategy is electronic effect-controlled difunctionalization.5 When a functional group Scheme 1. Highly Regio- and Stereoselective Difunctionalization of Aliphatic Internal Alkenes
Received: August 21, 2018
© XXXX American Chemical Society
A
DOI: 10.1021/acs.orglett.8b02672 Org. Lett. XXXX, XXX, XXX−XXX
Letter
Organic Letters alcohols and protected CF3S 1,3-diols by neighboring group assistance (Scheme 1b).11 This proposed method not only provides a convenient pathway for the synthesis of 1,3-amino alcohol and 1,3-diol derivatives but also extends the scope of chiral CF3S molecules.12−15 According to our previous work,15 we considered that our proposal might be feasible. We hypothesized that a chiral selenide-captured thiiranium ion I could be formed in the transformation (Scheme 1c). Recently, we found that trisubstituted alkenes underwent intermolecular difunctionalization to form chiral CF3S tertiary alcohols by selenide catalysis, but the method was not effective for common 1,2disubstituted alkenes because reactivity and racemization derived from the relative instability of thiiranium ion intermediate were problematic.15g Although I is not relatively stable, it was envisioned that the attack by the tethered amide or ester group toward the thiiranium moiety could give II via a six-membered ring transition state. This intramolecular attack might overcome the issues of reactivity and racemization to guarantee high regio- and enantioselectivities. Then, the following hydrolysis leads to the products. When olefinic esters are utilized, the cleavage of C−Z on III is possible to form aroyl-migrated products. Herein, we report our discovery that olefinic imides can undergo regio- and enantioselective difunctionalization to give chiral CF3S amino alcohols by neighboring group assistance. Olefinic esters undergo similar conversion to form aroyl-migrated products. Furthermore, the same strategy is effective for the selective oxyhalofunctionalization of internal alkenes. Keeping the hypothesis in mind, we initiated our study on CF3S hydroxylation of olefinic amides. To successfully deliver the hydroxy group into the double bond of alkenes, a proper amide group would be pivotal to the entire transformation. Different amide groups were tested (Scheme 2). When
was chosen as the model substrate (Table 1). When Bocprotected chiral selenide C1 was employed as the catalyst, it
Scheme 2. Screening of Functional Groups
was found that chiral product 3e was formed with only 10% ee, but in excellent diastereoselectivity (entry 1). To our delight, catalyst with a stronger hydrogen bond donor provided higher enantioselectivity (entry 2). By adjusting the steric hindrance of catalyst, the desired product was produced in higher ee by using catalyst C4 (entry 4). The reactivity and enantioselectivity of transformation was affected by reaction temperature. The lower the temperature was, the higher the enantioselectivity was, but the reactivity was worse (entries 5−7). To improve the reactivity of the reaction, the amounts of reagent 2a, acid, and water were studied. It was found that product was obtained in high isolated yield with excellent ee in the presence of 5 equiv of TfOH and 6 equiv of H2O. With the optimal conditions in hand, the scope of olefinic phthalimides was evaluated (Scheme 3). When the ethyl substituent on the double bond was replaced by different alkyl groups, the electrophilic reactions proceeded smoothly to afford the corresponding products in high yields with high enantioselectivities and excellent diastereoselectivities. It is noted that a chloro substituent tolerated the conditions (3j and 3k). Furthermore, substituents, i.e., −Cl and −Me, on the phenyl ring of the phthalimde group had a slight impact on the reactivity and selectivity. The corresponding products were obtained in high yields and good stereoselectivities. Olefinic succinimide also underwent the difunctionalization to afford alcohol 3n well. In contrast, olefinic saccharimide 1d generated the desired product 3d in good yield, but with 82% enantioselectivity. This result indicates that the imide group
Table 1. Condition Optimization of Enantioselective CF3S Hydroxylation of Alkenea
entry
cat.
temp (°C)
yieldb (%)
eec (%)
1 2 3 4 5 6 7 8d 9e 10f
C1 C2 C3 C4 C4 C4 C4 C4 C4 C4
rt rt rt rt −20 −40 −78 −78 −78 −78
67 75 99 >99 92 51 18 41 68 89 (91)
10 47 55 59 74 81 94 93 92 90
a
Conditions: 1e (0.05 mmol), 2a (1.2 equiv), H2O (2.0 equiv), TfOH (1.0 equiv), catalyst (20 mol %), CH2Cl2 (1.0 mL), 12 h, under N2 atmosphere. Unless noted, all of the diastereoselectivities are >99:1. bRefers to NMR yield using PhCF3 as the internal standard. Isolated yield on a 0.1 mmol scale is shown in parentheses. c Determined by HPLC analysis. dTfOH (2.0 equiv). eTfOH (3.0 equiv). f2a (1.5 equiv), TfOH (5.0 equiv), H2O (6.0 equiv).
benzamide was protected by a methyl group, selenide-catalyzed difunctionalization did not work at all. Benzamide 1b with free NH gave the complex owing to the competitive cyclization reaction. To enhance the reactivity, sulfamide 1c was employed, but afforded no desired product because of its decomposition. Gratifyingly, the use of olefinic saccharimide 1d allowed the reaction in full conversion to form the desired product in high regioselectivity with 16:1 diastereoselectivity, which proves the feasibility of this difunctionalization strategy. When phthalimide 1e was utilized, the diastereoselectivity was further improved. The success of nonasymmetric difunctionalization promoted us to explore an asymmetric version. On the basis of the efficiency of the phthalimide group, olefinic phthalimide 1e B
DOI: 10.1021/acs.orglett.8b02672 Org. Lett. XXXX, XXX, XXX−XXX
Letter
Organic Letters
when the reactions were performed under similar conditions, terminal alcohols as the products were obtained instead of direct HO-trifluoromethylthiolation products via an aroyl group migration in high enantioselectivities and excellent diastereoselectivities. It is noteworthy that substrates with a methyl group directly connecting to the double bond gave products in higher ee’s than the analogous ones with an ethyl group (5a, 89% ee vs 5b, 95% ee; 5f, 88% ee vs 5g, 93% ee). The increase of steric hindrance of substrates slightly affected the enantioselectivity of products (5d, 89% ee). Different aroyl-protected olefinic esters could be transformed to the corresponding products efficiently (5h−l). In these transformations, three different functional groups are formed simultaneously, which provides a convenient route for the synthesis of 1,3-diol derivatives bearing a terminal hydroxy group and a protected secondary hydroxy group without an additional protection−deprotection step. Halogenation of alkenes is a very important transformation. The oxybromination of olefinic imides and esters was attempted to carry out under similar chiral selenide-catalyzed conditions;16 however, only racemic difunctionalization products were formed at −78 °C. After further optimization of conditions, the racemic brominated and iodinated products were generated in good regio- and diastereoselectivities by acid only (eqs 1 and 2). As shown in eq 1, bromohydroxylation of
Scheme 3. Scope of Enantioselective CF3S Hydroxylation of Olefinic Imidesa
a
Conditions: 1 (0.10 mmol), 2a (1.5 equiv), H2O (6.0 equiv), TfOH (5.0 equiv), C4 (20 mol %), CH2Cl2 (2.0 mL), −78 °C (at −60 °C for 3j and 3k), 12 h, under N2 atmosphere. The ee value was determined by HPLC analysis.
is important for delivering the high enantioselectivity of the reaction. The same strategy was applied to the difunctionalization of readily accessible olefinic esters (Scheme 4). Surprisingly, Scheme 4. Enantioselective CF3S Esterification of Olefinic Estersa
olefinic phthalimides proceeded efficiently to afford the corresponding products in good yields by solo TfOH catalysis (6a−c, 60−85% yields). Olefinic esters underwent bromo- and iodohydroxylation to give the corresponding products in good yield with excellent diastereoselectivities as well. Due to the good transformation of halo groups, this method provides a good pathway for the diversified achiral 1,3-amino alcohol and 1,3-diol derivatives. Furthermore, when alkynyl imide was utilized as the substrate, α-functionalized ketone as the desired product was achieved in excellent regioselectivity by selenide catalysis (eq 3). To ensure that the incorporated hydroxy group is formed by neighboring group assistance and not from water, the 18Olabeling experiments were conducted. When the difunctionalization of olefinic ester 4a was carried out in the presence of H218O, the product with 18O labeling was obtained in good yield and identified by MS. Then product 5a′ was deprotected under basic conditions. A diol product 10 was formed. The analysis of its MS revealed that the molecule did not contain an
a
Conditions: 4 (0.10 mmol), 2a (1.5 equiv), the other conditions are same as described in Scheme 3 (at −40 °C for 5e). Unless noted, all of the diastereoselectivities are >99:1. C
DOI: 10.1021/acs.orglett.8b02672 Org. Lett. XXXX, XXX, XXX−XXX
Letter
Organic Letters 18
(e) Yin, G.; Mu, X.; Liu, G. Acc. Chem. Res. 2016, 49, 2413. (f) Cheng, Y. A.; Yu, W. Z.; Yeung, Y.-Y. Org. Biomol. Chem. 2014, 12, 2333. (g) Lan, X.-W.; Wang, N.-X.; Xing, Y. Eur. J. Org. Chem. 2017, 5821. (2) For selected examples by nonorganocatalysis, see: (a) Raghavan, S.; Rajender, A.; Joseph, S. C.; Rasheed, M. A.; Kumar, K. R. Tetrahedron: Asymmetry 2004, 15, 365. (b) Pathak, T. P.; Gligorich, K. M.; Welm, B. E.; Sigman, M. S. J. Am. Chem. Soc. 2010, 132, 7870. (c) Kalyani, D.; Satterfield, A. D.; Sanford, M. S. J. Am. Chem. Soc. 2010, 132, 8419. (d) Phipps, R. J.; McMurray, L.; Ritter, S.; Duong, H. A.; Gaunt, M. J. J. Am. Chem. Soc. 2012, 134, 10773. (e) Cresswell, A. J.; Davies, S. G.; Lee, J. A.; Morris, M. J.; Roberts, P. M.; Thomson, J. E. J. Org. Chem. 2012, 77, 7262. (f) Huang, D.; Liu, X.; Li, L.; Cai, Y.; Liu, W.; Shi, Y. J. Am. Chem. Soc. 2013, 135, 8101. (g) Talbot, E. P. A.; Fernandes, T. A.; McKenna, J. M.; Toste, F. D. J. Am. Chem. Soc. 2014, 136, 4101. (h) Zhu, H.; Chen, P.; Liu, G. J. Am. Chem. Soc. 2014, 136, 1766. (i) Liu, Z.; Zeng, T.; Yang, K. S.; Engle, K. M. J. Am. Chem. Soc. 2016, 138, 15122. (j) Wu, Z.; Wang, D.; Liu, Y.; Huan, L.; Zhu, Z. J. Am. Chem. Soc. 2017, 139, 1388. (k) Liu, Z.; Ni, H.-Q.; Zeng, T.; Engle, K. M. J. Am. Chem. Soc. 2018, 140, 3223. (3) For selected examples by organocatalysis, see: (a) MacDonald, M. J.; Schipper, D. J.; Ng, P. J.; Moran, J.; Beauchemin, A. M. J. Am. Chem. Soc. 2011, 133, 20100. (b) Alix, A.; Lalli, C.; Retailleau, P.; Masson, G. J. Am. Chem. Soc. 2012, 134, 10389. (c) Zhang, W.; Liu, N.; Schienebeck, C. M.; Zhou, X.; Izhar, I. I.; Guzei, I. A.; Tang, W. Chem. Sci. 2013, 4, 2652. (d) Banik, S. M.; Medley, J. W.; Jacobsen, E. N. J. Am. Chem. Soc. 2016, 138, 5000. (e) Muñiz, K.; Barreiro, L.; Romero, R. M.; Martínez, C. J. Am. Chem. Soc. 2017, 139, 4354. (f) Lu, Y.; Nakatsuji, H.; Okumura, Y.; Yao, L.; Ishihara, K. J. Am. Chem. Soc. 2018, 140, 6039. (4) (a) Denmark, S. E.; Kalyani, D.; Collins, W. R. J. Am. Chem. Soc. 2010, 132, 15752. (b) Denmark, S. E.; Kornfilt, D. J. P.; Vogler, T. J. Am. Chem. Soc. 2011, 133, 15308. (c) Denmark, S. E.; Jaunet, A. J. Am. Chem. Soc. 2013, 135, 6419. (d) Chen, F.; Tan, C. K.; Yeung, Y.Y. J. Am. Chem. Soc. 2013, 135, 1232. (e) Denmark, S. E.; Chi, H. M. J. Am. Chem. Soc. 2014, 136, 8915. (f) Denmark, S. E.; Hartmann, E.; Kornfilt, D. J. P.; Wang, H. Nat. Chem. 2014, 6, 1056. (g) Denmark, S. E.; Chi, H. M. J. Org. Chem. 2017, 82, 3826. (h) Denmark, S. E.; Kornfilt, D. J. P. J. Org. Chem. 2017, 82, 3192. (i) Tao, Z.; Robb, K. A.; Zhao, K.; Denmark, S. E. J. Am. Chem. Soc. 2018, 140, 3569. (5) (a) Soltanzadeh, B.; Jaganathan, A.; Staples, R. J.; Borhan, B. Angew. Chem., Int. Ed. 2015, 54, 9517. (b) Xi, Y.; Butcher, T. W.; Zhang, J.; Hartwig, J. F. Angew. Chem., Int. Ed. 2016, 55, 776. (c) Soltanzadeh, B.; Jaganathan, A.; Yi, Y.; Yi, H.; Staples, R. J.; Borhan, B. J. Am. Chem. Soc. 2017, 139, 2132. (6) (a) Evans, D. A.; Fu, G. C. J. Am. Chem. Soc. 1991, 113, 4042. (b) Scheideman, M.; Shapland, P.; Vedejs, E. J. Am. Chem. Soc. 2003, 125, 10502. (c) Scheideman, M.; Wang, G.; Vedejs, E. J. Am. Chem. Soc. 2008, 130, 8669. (d) Smith, S. M.; Takacs, J. M. J. Am. Chem. Soc. 2010, 132, 1740. (e) Nicolaou, K. C.; Simmons, N. L.; Ying, Y.; Heretsch, P. M.; Chen, J. S. J. Am. Chem. Soc. 2011, 133, 8134. (f) Morandi, B.; Wickens, Z. K.; Grubbs, R. H. Angew. Chem., Int. Ed. 2013, 52, 9751. (g) Hu, D. X.; Seidl, F. J.; Bucher, C.; Burns, N. Z. J. Am. Chem. Soc. 2015, 137, 3795. (h) Landry, M. L.; Hu, D. X.; McKenna, G. M.; Burns, N. Z. J. Am. Chem. Soc. 2016, 138, 5150. (i) Xi, Y.; Hartwig, J. F. J. Am. Chem. Soc. 2016, 138, 6703. (j) Derosa, J.; Tran, V. T.; Boulous, M. N.; Chen, J. S.; Engle, K. M. J. Am. Chem. Soc. 2017, 139, 10657. (7) (a) Schetter, B.; Mahrwald, R. Angew. Chem., Int. Ed. 2006, 45, 7506. (b) Lait, S. M.; Rankic, D. A.; Keay, B. A. Chem. Rev. 2007, 107, 767. (8) For molecules containing 1,3-amino alcohol moieties, see: (a) Sakai, R.; Kamiya, H.; Murata, M.; Shimamoto, K. J. Am. Chem. Soc. 1997, 119, 4112. (b) Carlier, P. R.; Lo, M. M.-C.; Lo, P. C.-K.; Richelson, E.; Tatsumi, M.; Reynolds, I. J.; Sharma, T. A. Bioorg. Med. Chem. Lett. 1998, 8, 487. (c) Benedetti, F.; Norbedo, S. Chem. Commun. 2001, 203. (d) Lee, H.-S.; Kang, S. H. Synlett 2004, 1673. For molecules containing 1,3-diol moieties, see: (e) Rychnovsky, S. D. Chem. Rev. 1995, 95, 2021. (f) Koskinen, A. M. P.; Karisalmi, K.
O atom. These facts confirm that the hydroxy group is not from water. At the same time, the similar 18O-labeling experiments were also conducted with olefinic imide 1h. The same result was obtained (see the Supporting Information).
In conclusion, we have developed a highly regio-, enantio-, and diastereoselective oxytrifluoromethylthiolation of aliphatic internal alkenes to synthesize CF3S-substituted 1,3-amino alcohol and 1,3-diol derivatives in a formally intermolecular fashion by chiral selenide catalysis. This method is also effective for the stereoselective halogenation of internal alkenes and the conversion of internal alkynes. Importantly, this work contains a strategy that alkenes can be regioselectively functionalized by neighboring imide or ester group to deliver a functional group.
■
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.orglett.8b02672. Experimental details, characterization data, HPLC traces, and NMR spectra of new compounds (PDF) Accession Codes
CCDC 1841798−1841799 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
[email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
■
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. ORCID
Xiaodan Zhao: 0000-0002-2135-5121 Author Contributions †
J.X. and Y.Z. contributed equally to this work.
Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS We thank Sun Yat-Sen University, the “One Thousand Youth Talents” Program of China, the National Natural Science Foundation of China (Grant No. 21772239), and the Natural Science Foundation of Guangdong Province (Grant No. 2014A030312018) for financial support.
■
REFERENCES
(1) For recent reviews, see: (a) Muñiz, K. Chem. Soc. Rev. 2004, 33, 166. (b) Jensen, K. H.; Sigman, M. S. Org. Biomol. Chem. 2008, 6, 4083. (c) McDonald, R. I.; Liu, G.; Stahl, S. S. Chem. Rev. 2011, 111, 2981. (d) Tan, Ch. K.; Yeung, Y. Y. Chem. Commun. 2013, 49, 7985. D
DOI: 10.1021/acs.orglett.8b02672 Org. Lett. XXXX, XXX, XXX−XXX
Letter
Organic Letters Chem. Soc. Rev. 2005, 34, 677. (g) Weissman, K. J.; Müller, R. Nat. Prod. Rep. 2010, 27, 1276. (9) (a) Hansch, C.; Leo, A.; Unger, S. H.; Kim, K. H.; Nikaitani, D.; Lien, E. J. J. Med. Chem. 1973, 16, 1207. (b) Hansch, C.; Leo, A.; Taft, R. W. Chem. Rev. 1991, 91, 165. (c) Biffinger, J. C.; Kim, H. W.; DiMagno, S. G. ChemBioChem 2004, 5, 622. (10) (a) Leroux, F.; Jeschke, P.; Schlosser, M. Chem. Rev. 2005, 105, 827. (b) Muller, K.; Faeh, C.; Diederich, F. Science 2007, 317, 1881. (c) Hagmann, W. K. J. Med. Chem. 2008, 51, 4359. (d) Purser, S.; Moore, P. R.; Swallow, S.; Gouverneur, V. Chem. Soc. Rev. 2008, 37, 320. (e) Manteau, B.; Pazenok, S.; Vors, J.-P.; Leroux, F. R. J. Fluorine Chem. 2010, 131, 140. (11) For functionalization of alkynes by the participation of neighboring amide and ester groups, see: (a) Li, F.-H.; Cai, Z.-J.; Yin, L.; Li, J.; Wang, S.-Y.; Ji, S.-J. Org. Lett. 2017, 19, 1662. (b) Qiu, G.; Li, Y.; Ma, L.; Zhou, H. Org. Chem. Front. 2017, 4, 1069. (c) Yuan, S.-T.; Zhou, H.; Gao, L.; Liu, J.-B.; Qiu, G. Org. Lett. 2018, 20, 562. (12) (a) Toulgoat, F.; Alazet, S.; Billard, T. Eur. J. Org. Chem. 2014, 2415. (b) Xu, X.-H.; Matsuzaki, K.; Shibata, N. Chem. Rev. 2015, 115, 731. (c) Shao, X.; Xu, C.; Lu, L.; Shen, Q. Acc. Chem. Res. 2015, 48, 1227. (d) Barata-Vallejo, S.; Bonesi, S.; Postigo, A. Org. Biomol. Chem. 2016, 14, 7150. (13) For selected examples on the synthesis of achiral CF3Scompounds, see: (a) Ferry, A.; Billard, T.; Langlois, B. R.; Bacqué, E. Angew. Chem., Int. Ed. 2009, 48, 8551. (b) Chen, C.; Chu, L.; Qing, F.-L. J. Am. Chem. Soc. 2012, 134, 12454. (c) Zhu, L.; Wang, G.; Guo, Q.; Xu, Z.; Zhang, D.; Wang, R. Org. Lett. 2014, 16, 5390. (d) Pluta, R.; Nikolaienko, P.; Rueping, M. Angew. Chem., Int. Ed. 2014, 53, 1650. (e) Xu, C.; Ma, B.; Shen, Q. Angew. Chem., Int. Ed. 2014, 53, 9316. (f) Guo, S.; Zhang, X.; Tang, P. Angew. Chem., Int. Ed. 2015, 54, 4065. (g) Wu, H.; Xiao, Z.; Wu, J.; Guo, Y.; Xiao, J.-C.; Liu, C.; Chen, Q.-Y. Angew. Chem., Int. Ed. 2015, 54, 4070. (h) Yin, G.; Kalvet, I.; Englert, U.; Schoenebeck, F. J. Am. Chem. Soc. 2015, 137, 4164. (i) Mukherjee, S.; Maji, B.; Tlahuext-Aca, A.; Glorius, F. J. Am. Chem. Soc. 2016, 138, 16200. (j) Zhang, P.; Li, M.; Xue, X.-S.; Xu, C.; Zhao, Q.; Liu, Y.; Wang, H.; Guo, Y.; Lu, L.; Shen, Q. J. Org. Chem. 2016, 81, 7486. (k) Zheng, J.; Cheng, R.; Lin, J.-H.; Yu, D.-H.; Ma, L.; Jia, L.; Zhang, L.; Wang, L.; Xiao, J.-C.; Liang, S. H. Angew. Chem., Int. Ed. 2017, 56, 3196. (l) Jia, Y.; Qin, H.; Wang, N.; Jiang, Z.-X.; Yang, Z. J. Org. Chem. 2018, 83, 2808. (14) (a) Bootwicha, T.; Liu, X.; Pluta, R.; Atodiresei, I.; Rueping, M. Angew. Chem., Int. Ed. 2013, 52, 12856. (b) Wang, X.; Yang, T.; Cheng, X.; Shen, Q. Angew. Chem., Int. Ed. 2013, 52, 12860. (c) Deng, Q.-H.; Rettenmeier, C.; Wadepohl, H.; Gade, L.-H. Chem. - Eur. J. 2014, 20, 93. (d) Zhu, X.-L.; Xu, J.-H.; Cheng, D.-J.; Zhao, L.-J.; Liu, X.-Y.; Tan, B. Org. Lett. 2014, 16, 2192. (e) Zhao, B.-L.; Du, D.-M. Org. Lett. 2017, 19, 1036. (f) Zhang, Z.; Sheng, Z.; Yu, W.; Wu, G.; Zhang, R.; Chu, W.-D.; Zhang, Y.; Wang, J. Nat. Chem. 2017, 9, 970. (g) Zeng, J.-L.; Chachignon, H.; Ma, J.-A.; Cahard, D. Org. Lett. 2017, 19, 1974. (h) Jin, M. Y.; Li, J.; Huang, R.; Zhou, Y.; Chung, L. W.; Wang, J. Chem. Commun. 2018, 54, 4581. (15) (a) Luo, J.; Zhu, Z.; Liu, Y.; Zhao, X. Org. Lett. 2015, 17, 3620. (b) Liu, X.; An, R.; Zhang, X.; Luo, J.; Zhao, X. Angew. Chem., Int. Ed. 2016, 55, 5846. (c) Luo, J.; Liu, Y.; Zhao, X. Org. Lett. 2017, 19, 3434. (d) Luo, J.; Liu, X.; Zhao, X. Synlett 2017, 28, 397. (e) Zhu, Z.; Luo, J.; Zhao, X. Org. Lett. 2017, 19, 4940. (f) Luo, J.; Cao, Q.; Cao, X.; Zhao, X. Nat. Commun. 2018, 9, 527. (g) Liu, X.; Liang, Y.; Ji, J.; Luo, J.; Zhao, X. J. Am. Chem. Soc. 2018, 140, 4782. (16) A report about enantioselective oxybromination of internal alkenes via partial aroyl group migration under chiral phosphoric acid catalysis was reported a few days before submitting our manuscript. See: Cao, Y.-M.; Lentz, D.; Christmann, M. J. Am. Chem. Soc. 2018, 140, 10677.
E
DOI: 10.1021/acs.orglett.8b02672 Org. Lett. XXXX, XXX, XXX−XXX
