A Heterobimetallic Ga/Yb-Schiff Base Complex for Catalytic Asymmetric α-Addition of Isocyanides to Aldehydes

摘要

α-Additions of isocyanides with both electrophiles and nucleo-philes have been utilized for the synthesis of polyfunctional molecules since the early studies on Passerini and Ugi reactions. Although various diastereoselective a-additions of isocyanides using chiral substrates and/or chiral auxiliaries have been reported, the number of catalytic asymmetric methods is limited. To further improve catalytic activity and selectivity as well as substrate scope, the development of a new catalyst for asymmetric a-additions of isocyanides is highly desirable. Herein, we report a new heterodi-nuclear Ga/Yb-Schiff base complex for catalytic asymmetric a-additions of a-isocyanoacetamides to aldehydes, giving products in up to 98% ee.