Nonlinear Effects with Diastereomeric Ligand Mixtures in Enantioselective, Catalytic Additions of Terminal Alkynes Involving Copper-PINAP Complexes

A strong positive NLE has been observed with mixtures of ligand diastereomers in the addition of terminal allcynes to Medrums' acid-derived acceptors and imminium ions using PINAP ligands. This NLE is such that the diastereomeric ligand mixture obtained from synthesis (10-26% de) can be employed directly in the conjugate addition reaction or imminium additions, furnishing products in high ee.