Phosphine-catalyzed acyl-transfer of heteroaryl ketones for the construction of N-fused heterocycles

Abstract

An inexpensive phosphine catalyst was used effectively for a transition-metal-free acyl-transfer of N-containing heteroaryl ketones for the rapid synthesis of N-fused heterocycles. The key pre-aromatic spirocyclic intermediate initialized by the single electron transfer (SET) process of Togni's reagent II promoted by the tertiary phosphine resulted in an intriguing and alternative tactic for the cleavage of C‒C bonds. By using inexpensive tertiary phosphine as the catalyst, this skeleton-reorganizing approach of N-containing heteroaryl ketones allows a streamlined assembly of complex N-fused heterocycles with broad functional group tolerance.