Yb(OTf)3 catalysed regioselective synthesis of unusual di- and tri- substituted 3,4-dihydrothiochromeno[3,2-e][1,3]thiazin-5(2H)-one derivatives through a pseudo four-component hetero-Diels–Alder reaction

Abstract

An efficient and facile regioselective synthesis of di- and tri- substituted 3,4-dihydrothiochromeno[3,2-e][1,3]thiazin-5(2H)-one derivatives was reported from 4-hydroxydithiocoumarin, ammonium acetate/primary amines and aldehydes involving a ytterbium triflate catalysed pseudo four component hetero-Diels–Alder reaction. The significant features of the present protocol are: mild reaction conditions, shorter reaction time, good yields, and unusual ring closure leading to the formation of C–C, C–N and C–S bonds in a single step operation.