New Chiral Cu(I)-NHC Catalyst for Asymmetric Cyclopropanations

by Eddings, Daniel Bryant; Gawley, Robert E.

The synthesis of C2-sym. NHC-catalysts for use in several reactions has been a topic of recent interest in our group. To our knowledge, there are no reported chiral NHC ligands used for asym. cyclopropanations, or asym. cyclopropanations from stannyldiazoalkanes. Recent research in our group has shown that NHC-catalyzed reaction of stannyldiazo compds. with alkenes gives rise to diastereoenriched cyclopropanes in 50-71% yield and dr up to 95:5 (1). These high selectivities prompted us to explore the idea of a C-2 sym. Cu(I) NHC-catalyst for possible use in this and other reactions. Progress in this investigation will be presented.