Palladium-catalysed branch- and enantioselective allylic C–H alkylation of α-alkenes

Abstract

Enantioselective functionalization of alkenes is an attractive and straightforward method to assemble molecular complexity from readily available chemical feedstocks. Although regio- and enantioselective transformations of the C=C bond of alkenes have been extensively studied, those of the allylic C–H bonds of unactivated alkenes are yet to be explored. Here we report a palladium-catalysed branch- and enantioselective allylic C–H alkylation that is capable of accommodating diverse types of α-alkenes, ranging from feedstocks annually manufactured on a million-tonne scale to olefins tethering a wide scope of appended functionalities, providing unconventional access to chiral γ,δ-unsaturated amides. Notably, mechanistic studies reveal that regioselectivity is not only governed by the coordination pattern of nucleophiles but also regulated by the ligational behaviours of ligands, highlighting the importance of the monoligation of chiral phosphoramidite ligands in provoking high levels of stereo- and branch-selectivity via a nucleophile coordination-enabled inner-sphere allylation pathway.