Proximal and Remote Hydrocarboxylation of Alkenes with Carbon Dioxide Enabled by Nickel-Catalyzed Hydrogen Atom Transfer.

The utilization of carbon dioxide and alkenes as feedstocks for the synthesis of carboxylic acids holds great significance in the realm of sustainable chemistry. Nonetheless, achieving selective C─H bond carboxylation of alkenes with broad applicability has long been a challenging task. Herein, we present a straightforward and unifying approach for the preparation of α-carboxylic acids through nickel-catalyzed radical hydrocarboxylation of both functionalized and unactivated, simple alkenes, at proximal and remote sites. Notably, this operationally simple catalytic reaction exhibits a broad substrate scope, having excellent regio- and chemoselectivities, and is suitable for late-stage carboxylation of bioactive molecules. Preliminary mechanistic investigations showed that a nickel-catalyzed hydrogen atom transfer (Ni-HAT) pathway is in operation, accounting for the site-selective hydrocarboxylation protocol for various alkene substrates.