Stereoselective Synthesis of 4H-5,6-Dihydro-1,3-thiazines by the Reaction of 3-N-Acylamino Alcohols with Lawesson’s Reagent

Abstract

The 4H-5,6-Dihydro-1,3-thiazine derivatives 13−15 were obtained exclusively and stereoselectively in fair yields by treating the 3-N-acylamino alcohols 5−8 with an equimolar amount of Lawesson’s reagent (LR), while the corresponding thiols 9−12 were afforded stereoselectively when only 0.5 equiv. of LR was used in this reaction.