Metal-free divergent radical reactions of N-sulfonyl ynamides: substrate-controlled synthesis of α-sulfonyl amides and α-sulfonyl nitriles

Abstract

A substrate-controlled, metal-free strategy for the divergent synthesis of α-sulfonyl amides and nitriles from N-sulfonyl ynamides is disclosed. Under photocatalytic or thermal conditions, sulfonyl radicals initiate a radical chain process, where the reaction pathway is solely dictated by the substrate structure: non-allylic ynamides afford α-sulfonyl amides via hydration, while allylic ynamides exclusively yield α-sulfonyl nitriles through an aza-Claisen rearrangement. This method features broad functional-group tolerance, excellent scalability, and 100% atom economy for nitrile formation. This work represents the first general metal-free approach for achieving radical divergence in ynamide chemistry, offering a versatile platform for accessing valuable sulfonyl-containing building blocks.