A new route to privileged spirocyclic tetrahydroisoquinolines (spiroTHIQs) has been developed. The key step in which the spirocyclic system is formed in generally good yields and diastereoselectivity is the three-component Castagnoli-Cushman reaction of homophthalic anhydride, cyclic ketones and ammonium acetate. Decarboxylation of the initial adduct yields THIQ lactams which are reduced by lithium