Synfacts 2011(12): 1360-1360  
DOI: 10.1055/s-0031-1289371
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart ˙ New York

Asymmetric Reduction of Unprotected Indoles

Contributor(s): Benjamin List, Ji-Woong Lee
Y.-C. Xiao, C. Wang, Y. Yao, J. Sun*, Y.-C. Chen*
Chengdu Institute of Biology and Sichuan University, Chengdu, P. R. of China
Further Information

Publication History

Publication Date:
18 November 2011 (online)

Significance

Sun, Chen and co-workers report organocatalytic syntheses of 2,3-disubstituted chiral indolines by enantioselective hydrosilyation of unprotected 1H-indoles. In the presence of a strong Brønsted acid, HCl, indole substrates could be protonated at C3 to afford indolenium ions. The involvement of dynamic kinetic resolution of indolenium ions was supported by deuterium-labeling experiments. By employing chiral Lewis base catalysts A and B, various chiral indolines were obtained with high enantioselectivity. Moreover, 2,3-disubstituted indoles were converted into cis-indolines exclusively.