Facile Synthesis of Spiro[indane-2,1′-pyrrolo[2,1-a]isoquinolines] via Three-Component Reaction of Isoquinolinium Salts, Indane-1,3-dione, and Isatins

A series of novel 2'-aryl-2'-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-2',3'-dihydro-10b'H-spiro[indene-2,1'-pyrrolo[2,1-a]isoquinoline]-1,3-diones were efficiently synthesized by three-component reactions of in situ generated N-phenacylisoquinolinium bromides with indane-1,3-dione and isatins in ethanol with triethylamine as the base. A domino reaction mechanism for the formation of the spiro compounds was rationally proposed.