A highly enantioselective Mannich reaction of silyl ketene imines with isatin‐derived ketimines has been realized by using a chiral N,N′‐dioxide/ZnII catalyst. A variety of β‐amino nitriles containing congested vicinal tetrasubstituted stereocenters were obtained with excellent outcomes (up to 98 % yield, >19:1 d.r. and 99 % ee). Based on the experimental investigations, a possible transition state
Palladium-Catalyzed Highly Enantioselective Cycloaddition of Vinyl Cyclopropanes with Imines
作者:Xiao-Bing Huang、Xian-Jing Li、Tian-Tian Li、Bo Chen、Wen-Dao Chu、Long He、Quan-Zhong Liu
DOI:10.1021/acs.orglett.9b00274
日期:2019.3.15
Palladium-catalyzed asymmetric formal [3 + 2] cycloaddition of vinyl cyclopropanes and aldimines or isatin-derived ketimines proceeded smoothly in the presence of chiral phosphoramidite ligands. The corresponding highly functionalized and optically enriched pyrrolidine or spiro[pyrrolidin-3,2′-oxindole] derivatives are obtained in up to 94% yield and with up to 96% ee and 7:1 dr.
An asymmetric α-regioselective allenylation reaction of activated ketimines with 3-butynoates is disclosed under Cu(I) catalysis, probably via the generation of nucleophilic γ-allenylcopper species in the presence of diisopropylethylamine. A broad range of imines, derived from diverse ketones such as isatins, pyrazolediones, isoquinoline-1,3,4-triones, and even trifluoromethyl alkynyl ketones, can
Organocatalytic direct asymmetric vinylogous Mannich reaction of γ-butenolides with isatin-derived ketimines
作者:Yunlong Guo、Yong Zhang、Liangwen Qi、Fang Tian、Lixin Wang
DOI:10.1039/c4ra04824e
日期:——
The first directasymmetricvinylogous Mannich reaction of γ-butenolides with isatin-derived ketimines has been effectively realized promoted by a bifunctional quinidine-derived catalyst. A series of chiral 3-aminooxindole derivatives bearing adjacent tertiary and quaternary stereocenters with the butenolide moiety were obtained in excellent yields (up to 97%) and high enantioselectivities (up to 96%
An efficient asymmetric aza-Henryreaction of isatin-derived ketimines has been achieved by using a chiral guanidine–amide organocatalyst. A series of 3-substituted 3-amino-2-oxindoles was obtained with excellent results (up to 99% yield, 94% ee). Other functionalized derivatives were also conveniently transformed. This metal-free system was convenient, practical, and insensitive to air and moisture