NHC-Catalyzed Spiro Bis-Indane Formation via Domino Stetter−Aldol−Michael and Stetter−Aldol−Aldol Reactions

Two novel domino NHC-catalyzed spirocyclizations are described herein, enabling the rapid construction of three new carbon−carbon bonds and a quaternary center with high diastereoselectivity. A variety of spiro bis-indane structures are assembled in a single step from simple o-phthaldialdehyde derivatives.