Abstract
Herein, we present the design of a new class of Rh-bound protic N-allyl enammonium ylides and its stereoselective 3-aza-Cope rearrangement. These transient ylides are generated in situ by the Rh-catalyzed reaction of vinyldiazo com-pounds and N-secondary-(Z)--enamino carbonyl compounds, under mild conditions. Mechanistic studies revealed that the resonance-assisted hydrogen bonding (RAHB) of protic enammonium ylide promotes exclusively [3,3] rear-rangement by disfavouring both 1,2-proton transfer (NH-insertion) and direct carbenoid C-C bond formation. This new reaction was used in the synthesis of multi-substituted pyrroles, dihydropyrroles, deuterated pyrroles, tetrahy-droindoles, and pyrroloindole scaffold of an antitumor and UV-protecting agent terreusinone.