Tropos Benzophenone-like Phosphoramidite Ligands: Highly Enantioselective Catalyses of Conjugate Addition to Nitroalkenes irrespective of the Reagents and Substrates

摘要

The key to efficient asymmetric catalysis has long lied in the design of chirally rigid, particularly atropisomeric (atropos in Greek), ligands to attain high enantioselectivity. However, even higher enantioselectivity has recently been reported by chirally flexible (tropos) achiral benzophenone-derived diphosphine ligands, of which the chirality is instantaneously controlled by a chiral activator (A~*-A) via central metals (M=Ru, Rh, Pd, and Pt) (Scheme 1a).