1,4-Addition of Arylboronic Acids to p-Aryl-alpha,beta-unsaturated Ketones and Esters Catalyzed by a Rhodium(I)-chiraphos Complex

摘要

1,4-Additions of electrophiles to alpha,beta-unsaturated carbonyl compounds are a versatile methodology for forming carbon-carbon bonds. Since the reaction yields a stereogenic center at the beta-carbon, considerable efforts have been devoted to the development of asymmetric syntheses via metal-catalyzed 1,4-addition of organoboron and other metal reagents to cyclic and acyclic alpha,beta-unsaturated carbonyl compounds. Among these extensive studies on 1,4-addition, the synthesis of beta-diaryl carbonyl ketones or esters (4) has attracted much attension in recent years. In this paper, we show the efficiency of a rhodium(I)-chiraphos complex (3) for enantioselective preparation of beta-diaryl carbonyl compounds (4) via the 1,4-addition of arylboronic acids (2) to beta-aryl-alpha,beta-unsaturated ketones or esters (1) (Scheme 1).