Dearomatizing Phenols with Internal Thioamides using Hypervalent Iodine: Accessing 2,2'-Aminothiol-Substituted Biphenyls

Herein, we report that spirocyclohexadienone-fused 1,3benzothiazine scaffolds are efficiently synthesized by dearomatizing phenols bearing internal thioamide nucleophiles using hypervalent iodine. The reaction proceeds under mild conditions and exhibits good substrate scope. The resulting spirocyclic products were further transformed into 2,2'-aminothiol-substituted biphenyl derivatives via sequential ketone reduction and rearrangement. X-ray crystallography revealed that the S-C(sp 3 ) bond selectively migrates during the rearrangement process. This method provides a novel approach for synthesizing sulfur-containing heterocycles and structurally unique biphenyl frameworks.