Regioselective Syntheses of 1,2‐Benzothiazine 1‐Imines by Rhodium‐Catalyzed Annulation Reactions of Sulfondiimines

Unprecedented 1,2‐benzothiazine 1‐imines have been prepared from sulfondiimines by regioselective rhodium‐catalyzed annulation reactions with diazo keto esters and α‐substituted (pseudo)halo acetophenones as coupling partners. A representative product was characterized by single crystal X‐ray structure analysis, and the applicability of the resulting three‐dimensional heterocycles to Buchwald‐Hartwig‐type amination reactions is shown.