Sequential Carboborylation–Suzuki Coupling of α,β‐Unsaturated Tosylhydrazones: A Dual CC Bond‐Forming Strategy for Molecular Diversification

The one‐pot three‐component process involving N‐tosylhydrazones derived from cyclic α,β‐unsaturated ketones, alkylboronic acids, and aryl halides is reported. This transformation features a sequential reaction: a photochemical carboborylation of the N ‐tosylhydrazone generates an allylboronic acid intermediate, which undergoes a Pd‐catalyzed allyl–Suzuki cross‐coupling. The overall sequence enables the formation of two new CC bonds—one at the former carbonyl carbon and another at the β‐position—resulting in an unprecedented functionalization of α,β‐unsaturated carbonyl compounds via their N ‐tosylhydrazone derivatives. The methodology exhibits broad scope across all three components, accommodating both primary and secondary alkyl substituents at the carbonyl position and a wide range of aryl and heteroaryl groups at the β‐position. Furthermore, the reaction is compatible with various cyclic ketone scaffolds, including substituted cyclohexanones, pyranones, and piperidones. Notably, application to nitrogen‐containing heterocycles allows for the synthesis of 2‐aryl‐substituted tetrahydropyridines—an important class of privileged structures in medicinal chemistry.