Metallaphotoredox Decarboxylative Cross‐Nucleophile Coupling of Diaryl Hydrazines via Hydrogen Evolution

A visible light‐driven cross‐nucleophile coupling strategy for the synthesis of acyl hydrazides is reported. In contrast to conventional acylation methods, this approach merges diaryl hydrazines and α‐oxo acids through a dehydrogenative and decarboxylative metallaphotoredox process. An azobenzene intermediate is generated in situ and is intercepted by acyl radicals formed through decarboxylation. The transformation is enabled by a photostable pyrylium photocatalyst in combination with a cobaloxime cocatalyst under mild conditions, without external oxidants, producing only CO ₂ and H ₂ as byproducts. A broad range of substrates is tolerated, providing acyl hydrazides in moderate to high yields.