A Direct and an Efficient Regioselective Synthesis of 1,2-Benzothiazine 1,1-dioxides, β-Carbolinones, Indolo[2,3-<i>c</i>]pyran-1-ones, Indolo[3,2-<i>c</i>]pyran-1-ones, Thieno[2,3-<i>c</i>]pyran-7-ones and Pyrano[3’,4’:4,5]imidazo[1,2-<i>a</i>]pyridin-1-ones via Tandem Stille/Heterocyclization Reaction

Abstract

A general regioselective one-pot synthesis of 1,2-benzothiazine 1,1-dioxides from 2-iodo benzenesulfonamide moieties and allenylstannanes is described using a domino Stille-like/Azacyclization reaction. The conditions developed also opened a novel access to β-carbolinones, indolopyranones, thienopyranones and pyrano-imidazopyridines.

Keywords

• regioselective synthesis
• 1,2-benzothiazine 1,1-dioxides
• β-carbolinones
• indolo[2,3-<i>c</i>] and [3,2-<i>c</i>]pyrane-1-one derivatives
• Stille/Heterocyclization reaction