Organic Letters
Letter
C4−C6 on the aniline ring were examined. The desired silane-
containing 3,3′-disubstituted oxindoles 3a−3h were formed in
52−90% yields in the presence of CuOAc catalyst at room
temperature.
Authors
Ren-Xiao Liang − College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis
Technology, Zhejiang University of Technology, Hangzhou
310014, China
A tentative reaction mechanism is depicted in Scheme 4.
The active species CuOtBu is first formed by the reaction of
Scheme 4. Proposed Mechanism
Ru-Yi Chen − College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis
Technology, Zhejiang University of Technology, Hangzhou
310014, China
Chao Zhong − College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis
Technology, Zhejiang University of Technology, Hangzhou
310014, China
Jia-Wen Zhu − College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis
Technology, Zhejiang University of Technology, Hangzhou
310014, China
Zhong-Yan Cao − College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis
Technology, Zhejiang University of Technology, Hangzhou
310014, China
CuOAc with KOtBu. Subsequently, organocopper intermedi-
ates of CuI−Bpin or CuI−SiMe2Ph are generated through the
transmetalation of CuOtBu with B2pin2 or PhMe2Si-Bpin. The
following borylcupration or silylcupration via the insertion of
the CC bond to CuI−Bpin or CuI−SiMe2Ph leads to alkyl-
Cu species I. The intramolecular coupling of alkyl-Cu with the
CAr−I bond affords either borylated or silylated 3,3′-
disubstituted oxindoles 2 or 3 and releases catalyst precursor
CuI.8 Finally, the catalytic cycle is finished by the conversion of
CuI to CuOtBu through an anionic exchange. Two possible
pathways are as follows: (1) the oxidative addition of alkyl-Cu
to CAr−I followed by reductive elimination of the Cu(III)
species generated and (2) the nucleophilic aromatic sub-
stitution of alkyl-Cu with iodoarene might account for the
conversion of intermediate I to product. The detailed
mechanism could not be concluded at this stage, although an
oxidative addition/reductive elimination sequence is more
likely.13
In summary, we have developed a highly efficient copper-
catalyzed arylboration and arylsilylation reaction of alkenes. A
range of borylated or silylated 3,3′-disubstituted oxindoles are
obtained in moderate to excellent yields in the reaction of N-
(2-iodoaryl)acrylamide with B2pin2 or PhMe2Si-Bpin. The
present protocol provides an alternative access to function-
alized oxindoles, which featured high efficiency, a broad scope,
and mild reaction conditions by using a simple copper salt as
the sole catalyst.
Complete contact information is available at:
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The project was supported by the National Natural Science
Foundation of China (Nos. 21702184, 21772175, and
91956117).
REFERENCES
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(1) For reviews: (a) Fu, X.; Zhao, W. Youji Huaxue 2019, 39, 625−
647. (b) Yin, G.; Mu, X.; Liu, G. Acc. Chem. Res. 2016, 49, 2413−
2423. (c) Schultz, D. M.; Wolfe, J. P. Synthesis 2012, 44, 351−361.
(2) Liu, Z.; Gao, Y.; Zeng, T.; Engle, K. M. Isr. J. Chem. 2019, 59,
(3) For the Pd-catalyzed arylboration of alkenes: (a) Shen, C.;
Zeidan, N.; Wu, Q.; Breuers, C. B. J.; Liu, R.-R.; Jia, Y.-X.; Lautens, M.
Chem. Sci. 2019, 10, 3118−3122. (b) Liu, Z.; Chen, J.; Lu, H.-X.; Li,
X.; Gao, Y.; Coombs, J. R.; Goldfogel, M. J.; Engle, K. M. Angew.
Chem., Int. Ed. 2019, 58, 17068−17073. (c) Yang, K.; Song, Q. Org.
Lett. 2016, 18, 5460−5463. (d) Wei, F.; Wei, L.; Zhou, L.; Tung, C.-
H.; Ma, Y.; Xu, Z. Asian J. Org. Chem. 2016, 5, 971−975. (e) Yang, K.;
Song, Q. Org. Lett. 2016, 18, 5460−5463. (f) Vachhani, D. D.; Butani,
H. H.; Sharma, N.; Bhoya, U. C.; Shahb, A. K.; der Eycken, E. V. V.
Chem. Commun. 2015, 51, 14862−14865.
(4) For the Ni-catalyzed arylboration of alkenes: (a) Wang, W.;
Ding, C.; Pang, H.; Yin, G. Org. Lett. 2019, 21, 3968−3971.
(b) Logan, K. M.; Sardini, S. R.; White, S. D.; Brown, M. K. J. Am.
Chem. Soc. 2018, 140, 159−162.
ASSOCIATED CONTENT
* Supporting Information
■
sı
The Supporting Information is available free of charge at
(5) For the Pd/Cu-cocatalyzed arylboration of alkenes: (a) Berg-
mann, A. M.; Dorn, S. K.; Smith, K. B.; Logan, K. M.; Brown, M. K.
Angew. Chem., Int. Ed. 2019, 58, 1719−1723. (b) Kuang, Z.; Li, B.;
Song, Q. Chem. Commun. 2018, 54, 34−37. (c) Logan, K. M.; Brown,
M. K. Angew. Chem., Int. Ed. 2017, 56, 851−855. (d) Sardini, S. R.;
Brown, M. K. J. Am. Chem. Soc. 2017, 139, 9823−9826. (e) Smith, K.
B.; Brown, M. K. J. Am. Chem. Soc. 2017, 139, 7721−7724. (f) Chen,
B.; Cao, P.; Yin, X.; Liao, Y.; Jiang, L.; Ye, J.; Wang, M.; Liao, J. ACS
Catal. 2017, 7, 2425−2429. (g) Chen, B.; Cao, P.; Yin, X.; Liao, Y.;
Jiang, L.; Ye, J.; Wang, M.; Liao, J. ACS Catal. 2017, 7, 2425−2429.
Experimental procedures, characterization data for all
products, NMR spectra (PDF)
AUTHOR INFORMATION
Corresponding Author
■
Yi-Xia Jia − College of Chemical Engineering, State Key
Laboratory Breeding Base of Green-Chemical Synthesis
Technology, Zhejiang University of Technology, Hangzhou
C
Org. Lett. XXXX, XXX, XXX−XXX