Practical synthesis of polysubstituted naphthalene derivatives via HNTf2-catalyzed benzannulation reaction

The synthesis of polysubstituted naphthalenes using the triflimide-catalyzed benzannulation of arylacetaldehydes with alkynes at room temperature is described. This method demonstrates a high functional group tolerance and, in the case of halogen substituted naphthalenes, opens the route for further functionalization by palladium-catalyzed cross-coupling reactions. With an analogous organocatalytic strategy, arylepoxides or 2-arylacetal derivatives are also suitable partners in the related benzannulation reactions with aryl-alkynes.