Rhodium-Catalyzed Reaction of Diazoacetates, Thiols and Azodicarboxylates: An Unusual 1,2-Aza Shift from a Sulfonium Ylide

A one-pot reaction of diazoacetates, thiols and azodicarboxylates in the presence of a dirhodium acetate catalyst gave N, S-ketals in good yields. This reaction proceeded via an unusual 1,2-aza shift from a sulfonium ylide intermediate.