Photochemical Asymmetric Palladium-Catalyzed Allylation Reaction: Expeditious Entry to Chiral 1,2-Amino Alcohols and 1,2-Diamines

The construction of diverse alkylamines is of importance in drug discovery and natural product synthesis. Herein, we report an efficient photoredox/palladium dual catalysis for the construction of protected 1,2-amino alcohols and 1,2-diamines via asymmetric allylation of α-silyl amines with heteroatom-substituted allenes and 1,3- dienes. This protocol is characterized by its mild conditions, excellent regio-, enantioselectivity, and wide substrate scope, including aliphatic amines or N-heterocyclic substrates especially. Computational and experimental mechanistic studies indicate that the reaction proceeds through a sequence of oxidative addition of Pd(0) catalyst by PPTS, allene insertion, outer-sphere radical substitution-type C–C bond formation, and reduction of Pd(I) by Ir(II). Thereinto, the outer-sphere radical substitution is the enantio- and regio-selectivity determining step.