Enantioselective synthesis of homoallylic amines through reactions of (pinacolato)allylborons with aryl-, heteroaryl-, alkyl-, or alkene-substituted aldimines catalyzed by chiral C 1-symmetric NHC-Cu complexes

Article abstract of DOI:10.1021/ja200311n

A catalytic method for enantioselective synthesis of homoallylamides through Cu-catalyzed reactions of stable and easily accessible (pinacolato)allylborons with aryl-, heteroaryl-, alkyl-, or alkenyl-substituted N-phosphinoylimines is disclosed. Transformations are promoted by 1-5 mol % of readily accessible NHC-Cu complexes, derived from C₁-symmetric imidazolinium salts, which can be prepared in multigram quantities in four steps from commercially available materials. Allyl additions deliver the desired products in up to quantitative yield and 98.5:1.5 enantiomeric ratio and are amenable to gram-scale operations. A mechanistic model accounting for the observed selectivity levels and trends is proposed.