A chemoselective electrochemical birch carboxylation of pyridines

Abstract

Nucleophilic addition to pyridiniums, metal-catalyzed hydrogenation, and cycloadditions constitute a valuable toolbox of modern pyridine dearomatization strategies. Though, in recent years, there have been notable improvements and variations of the canonical Birch reduction to address its notorious safety hazards and poor chemoselectivity, it remains an unexplored mode of reactivity for controlled pyridine dearomatization. Here, we report a simple and safe protocol for the electrochemical Birch carboxylation of pyridines utilizing a sustainable approach and CO₂ as a green C1 building block. This reaction is highly selective for pyridine reduction in the presence of several functional groups incompatible with the canonical Birch reduction and enables direct access to decorated piperidine scaffolds.