The base-mediated cyclization of selected benzyl alkynyl sulfones with aromatic aldehydes: novel synthetic access to aryl-substituted 5,6-dihydro-1,4-oxathiin S,S-dioxides

Based on an unexpected product isolated during the LDA-mediated intramolecular cyclization of a benzyl alkynyl sulfones, a conceptually new cyclization method for the formation of 5,6-dihydro-1,4-oxathiin S,S-dioxides is demonstrated. The reaction affords products with (het)aryl groups at the 5- and 6-positions in 754% yield. [GRAPHICS] .