COAP-Palladium-Catalyzed Asymmetric Linear Allylic Alkylation of Vinyl Benzoxazinanones for Multifunctional 3,3'-Disubstituted Oxindole Derivatives

A Pd-catalyzed enantioselective linear-allylic alkylation of vinyl benzoxazinanones with a series of 3-substituted oxindoles was reported in the presence of a chiral oxamide-phosphine ligand (COAP-Bn) under mild reaction conditions. A series of optically active multifunctional 3,3'-disubstituted oxindole derivatives bearing a quaternary stereogenic center and a linear aryl amino side chain were respectively obtained in 55-98% yields with 96-99% ee for 3-(hetero)aryl substituted oxindoles. The developed protocol demonstrates that the COAP ligands could serve as a privileged chiral ligand to construct diverse chiral 3,3-disubstituted oxindole compounds with various quaternary stereogenic centers, such as aza-, thio- or all-carbon quaternary stereogenic centers. The salient features of the method include broad substrate scope, N-protecting group free, base-free, and high regio- and enantioselectivity.