Palladium/TY‐Phos‐Catalyzed Asymmetric Intermolecular α‐Arylation of Aldehydes with Aryl Bromides

Abstract

AbstractDespite much progress has been made in the asymmetric α‐arylation reactions of cyclic ketones, lactones and lactams, the enantioselective α‐arylation of acyclic carbonyl compounds lagged much behind due to the in situ generated Z/E‐enolate intermediates leading to opposite enantiomers. Especially, the asymmetric α‐arylation of acyclic aldehydes is a long‐standing challenge, because of the highest activity among carbonyl compounds leading to various competitive side reactions. Herein we reported an efficient Pd‐catalyzed asymmetric intermolecular α‐arylation reaction of α‐alkyl‐α‐aryl disubstituted aldehydes with aryl bromides, which provides a rapid access to chiral aldehydes bearing an α‐all‐carbon quaternary stereocenter in moderate to good yields with good er in most cases. In addition, a pair of enantiomers could be easily prepared with the use of the same ligand by exchanging the aryl groups of aldehyde and aryl bromide.