NHC-BH3-Mediated Reduction of Sulfonyl Hydrazides into Disulfides and Further Cross-Coupling with Chlorostibine and Bioactivities

This paper presents a novel NHC-BH₃-promoted one-step synthesis of disulfides and stibine sulfides using odorless sulfonyl hydrazides. The protocol tolerates various functional groups as well as heterocyclic compounds. Mechanistic studies show that NHC-BH₃ plays two roles: (1) reducing sulfonyl hydrazides into disulfides and (2) promoting the cross-coupling of chlorostibine with the disulfides. The synthesized stibine sulfides also exhibit satisfactory anticancer activity against 4T1 and MDA-MB-231 cancerous cells.