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 and good functional-group tolerance, and enables the facile incorporation of natural-product-derived ynoates, delivering the products in good to excellent yields and enabling the development of potential biologically relevant spirocyclic scaffolds.