One-Pot Synthesis of Polysubstituted Benzenes through a N,N-dimethyl-4-aminopyridine (DMAP)-Catalyzed [4+2] Benzannulation of 1,3-Bis(sulfonyl)butadienes and γ-Substituted Allenoates.

A new strategy for the one-pot synthesis of polysubstituted benzenes through a N,N-dimethyl-4-aminopyridine (DMAP)-catalyzed [4+2] benzannulation from readily prepared 1,3-bis(sulfonyl)butadienes and gamma-substituted allenoates is described. This method provides a facile, metal-free and general route to highly substituted benzenes under mild conditions in moderate-to-good yields with complete regioselectivity.