Palladium‐Catalyzed Asymmetric Allylic Substitutions Achieved by C−N Axially Chiral N‐Arylpyrrole Derived Monophosphine Ligands

Abstract

Monophosphine ligands based on C–N axially chiral N‐Arylpyrrole backbones are prepared starting from amino acids and evaluated in Pd‐catalyzed asymmetric allylic substitutions. 20.7‐ 99.9% ees are achieved in the reactions of rac‐1,3‐diphenylallyl acetates with O‐, N‐ and C‐nucleophiles. Ligand screening revealed that the steric hindrance from 3‐ or 4‐ position of the pyrrole is crucial for the enantioselectivity of the reaction. The synthetic utilization of the products was demonstrated by the transformation of one product by a gold‐catalyzed oxidative rearrangement reaction.