Probing the origin of carboxylate migration selectivity in Rh 2 (II)-catalyzed N-heterocycle formation from trisubstituted styryl azides

Abstract Exposure of trisubstituted styryl azides to Rh 2 (II)-carboxylate catalyst triggers a tandem 4π-electron-5-atom electrocyclization–migration reaction. Herein we illustrate that the innate preference for selectivity of the carboxylate migration to form 3 H -indoles can be overcome by steric pressure to produce only 1,2,3-trisubstituted indoles.