New Synthesis of 2-Aryl- and 2-Hetarylpyrroles from 1-Propargylbenzotriazole

Abstract
1-(3-Lithiopropargyl)benzotriazole reacts with N-tosylarylimines to give adducts which undergo cycloelimination on treatment with ethanolic sodium hydroxide to afford 2-aryl- and 2-hetarylpyrroles in 45-60% yields. Treatment of 1-(1,3-dilithiopropargyl)benzotriazole successively with 1 equivalent of an alkyl halide followed by N-tosyl(1-naphthyl)imine and then ethanolic sodium hydroxide gives the corresponding 5-alkyl-2-(1-naphthyl)pyrroles in 43-56% yields.