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.
Asymmetric addition of alkyllithiums to N-alkylidene-α-naphthylethylamine was carried out. In the presence of BF3·OEt2, organolithiums reacted smoothly with the imine giving corresponding amines in high degrees of stereoselectivity (up to ∼100% de).
Development of an Asymmetric Trimethylenemethane Cycloaddition Reaction: Application in the Enantioselective Synthesis of Highly Substituted Carbocycles
作者:Barry M. Trost、Steven M. Silverman、James P. Stambuli
DOI:10.1021/ja207550t
日期:2011.12.7
azetidine structures, is discussed. The conditions developed to effect an asymmetric TMM reaction using 2-trimethylsilylmethyl allyl acetate were shown to be tolerant of a wide variety of alkene acceptors, providing the desired methylenecyclopentanes with high levels of enantioselectivity. The donor scope was also explored, and substituted systems were tolerated, including one bearing a nitrile moiety. These