Spiro-[indene-1,2'-indolin] Scaffolds via Rh (III) Catalyzed C-H Activation/[3+2] Spiroannulation

Abstract

An unprecedented [3+2] spiroannulation of 3,3-dimethyl-2-aryl-3H-indole with ynones/ynoates has been exemplified, furnishing architecturally ornamented C2-spiro-[indene-1,2'-indolin] scaffolds bearing an all-carbon C3-quaternary center proceeding via a Rh (III) catalytic cycle. The protocol exhibits broad substrate generality, good functional-group tolerance, and enables the facile incorporation of natural product-derived ynoates, delivering the product in good to excellent yields and for developing potential biologically relevant spirocyclic scaffolds.