Metalation Reactions; Part XIX. One-Step Synthesis of Five-Membered Heterocyclic Compounds Involving the Dilithiated Species 2-Lithio[(1-lithio-1-methylethyl)sulfonyl]benzene

Abstract

A novel synthesis is described for the preparation of five-membered heterocycles containing the sulfonyl group via dilithiation of (isopropylsulfonyl)benzene followed by reaction with gem-dihalo compounds, esters or acyl halides. Thus, 2,3-dihydro-1-benzothiophene 1,1-dioxides, 2,3-dihydro-1,3-benzothiasilole 1,1-dioxides and a 1,3-benzodithiole 1,1-dioxide are obtained in good yields.