Tricyclic imidazo[1,2-a]-indol-3-ones have been found in several classes of alkaloids. We report here an asymmetric approach to instal substituted imidazo[1,2-a]-indol-3-ones, which relied on a Pd/diamidophosphite-catalyzed intramolecular dearomative allylic substitution of 1,3-disubstituted indoles derived from 3-formylindoles and amino acids. Enantioselective total syntheses of (-)-spiroquinazoline and three related alkaloids were achieved.