Pd-Catalyzed Allylic Alkylation of <i>gem-</i>Alkyl,Aryl-Disubstituted Allyl Reagents with Ketones: Diastereoselective Construction of Vicinal Tertiary and Quaternary Carbon Centers

(E)-gem-Alkyl,aryl-disubstituted allyl carbonates can react with ketones under Pd catalysis using a commercially available NHC ligand by suppressing the β-H elimination. Ketones with α-tertiary, β-quaternary carbon stereocenters were produced in high yields with high regio- and diastereoselectivities. Kinetic resolution of the reaction product via CBS reduction afforded the optically active ketone as well as the alcohol with high enantioselectivity (S-factor = 35). The utility of the methodology was also demonstrated by transformations of the reaction products.