A formal [3 + 2] annulation reaction of propargyl sulfonium compounds and N-ylides: access to pyrrolo[2,1-a]quinolines, pyrrolo[2,1-a]phthalazines and indolizines

Abstract

A sequential [3 + 2] annulation of prop-2-ynylsulfonium salt and N-ylides was developed, leading to the formation of a series of pyrrolo[2,1-a]quinolines, pyrrolo[2,1-a]phthalazines and indolizines. The protocol featured the simultaneous one-pot formation of three new C–C bonds in moderate yields under mild conditions. In this reaction, the prop-2-ynylsulfonium salts acted as the C2 synthons and sulfide served as the leaving group. The resultant products could serve as useful precursors for the synthesis of diverse chemical compounds.