artificial catalysts for asymmetric synthesis. Polyfunctional catalysts are considered to be a promising tool for achieving excellent catalytic efficiency. A polyfunctional catalyst system was developed, which incorporates two Lewisacidic/Brønsted basic cobalt centers in combination with triazolium moieties that are crucial for high reactivity and excellent stereoselectivity in the direct1,4‐addition of
Catalytic asymmetric α‐arylation of N‐unprotected 3‐substituted oxindoles with diaryliodoniumsalts has been realized by a chiral Lewis acid promoted electrophilic addition and aryl‐rearrangement process. Single C3‐arylated products containing a quaternary carbon center were generated in high enantioselectivity and reactivity.
Quinidine derivative (QD)2PYR was found to catalyze the asymmetric direct amination of unprotected prochiral 3-oxindole with DIAD to construct quaternary stereocenters at the C3 position with excellent enantioselectivity.
An efficient enantioselective alkylation of N‐unprotected 3‐substitutedoxindoles was realized by using a chiral N,N′‐dioxide/scandium(III) complex as the catalyst. A wide range of 3,3‐dialkyl substitutedoxindoles with quaternary stereocenters were obtained in high yields and ee values (up to 98% yield and 99% ee).
Asymmetric hydroxyamination of oxindoles catalyzed by chiral bifunctional tertiary aminethiourea: construction of 3-amino-2-oxindoles with quaternary stereocenters
作者:Li-Na Jia、Jun Huang、Lin Peng、Liang-Liang Wang、Jian-Fei Bai、Fang Tian、Guang-Yun He、Xiao-Ying Xu、Li-Xin Wang
DOI:10.1039/c1ob06413d
日期:——
Chiral bifunctional tertiary amine thiourea was applied to catalyze the asymmetric hydroxyamination of 3-subsituted oxindoles with nitrosobenzene to construct 3-amino-2-oxindoles with quaternary stereocenters in good yields (up to 91%) and enantioselectivities (up to 90% ee).