Merging double hydrogen atom transfer and stepwise proton-coupled electron transfer for γ-C–H hydrazination of alcohols

Abstract

A cobalt(salen)-catalyzed γ-C–H hydrazination of alcohols is unveiled, merging a double hydrogen atom transfer (HAT) and a proton-coupled electron transfer (PCET) within a single catalytic cycle. The transformation harnesses metal–hydrogen atom transfer-induced radical translocation and electrophilic azodicarboxylate coupling to achieve remote C–H functionalization under mild and sustainable conditions. Mechanistic investigations (EPR, UV–vis, and spin-trapping) reveal cobalt oxidation state modulation and transient radical intermediates, while DFT analysis elucidates the double HAT/PCET pathway and site selectivity. This strategy offers an efficient and sustainable route from simple alcohols to γ-hydrazino and γ-amino alcohols.