Reaction of (2,2,3,3-tetrafluoropropyl)sulfenyl chloride with ethyl acrylate as a route to functionalized enamines and ring substituted 3,4-dihydro-2H-thiazine-1,1-dioxides

Abstract

An efficient two-step procedure of the preparation of (2,2,3,3-tetrafluoropropyl)sulfenyl chloride from 2,2,3,3-tetrafluoropropyl tosylate has been developed. (2,2,3,3-Tetrafluoropropyl)sulfenyl chloride readily reacted with ethyl acrylate giving the mixture of two regioisomeric products. The oxidation of the major regioisomer with hydrogen peroxide afforded ethyl 2-chloro-3-((2,2,3,3-tetrafluoropropyl)sulfonyl)propanoate. The latter compound was found to react with ammonia and aliphatic primary amines under basic conditions with the formation of the acyclic enamines whereas its reactions with aromatic amines afforded ethyl N-aryl-5-(difluoromethyl)-3,4-dihydro-2H-1,4-thiazine-3-carboxylate-1,1-dioxides.