Efficient capture of difluorocarbene by pyridinium 1,4-zwitterionic thiolates: A concise synthesis of difluoromethylene-containing 1,4-thiazine derivatives

A practical method for the construction of difluoromethylene-containing 1,4-thiazine moieties using readily available diethyl bromodifluoromethanephosphonate (BrCF2PO(OEt)2) as difluorocarbene precusor has been developed. This transformation features the efficient capture of difluorocarbene by pyridinium 1,4-zwotterionic thiolates. A series of structurally novel and functionalized difluoromethylene-containing 1,4-thiazine derivatives were thus synthesized in good yields.