I2-mediated Csp2-P bond formation via tandem cyclization of o-alkynylphenyl isothiocyanates with organophosphorus esters.

A novel, I2-mediated tandem cyclization of o-alkynylphenyl isothiocyanates with organophosphorus esters has been developed under mild conditions. Different kinds of 4H-benzo[d][1,3]thiazin-2-ylphosphonate could be synthesized in moderate to excellent yields. This method has the advantages of easy access to raw materials, free-metal catalyst, simple operation, high yield and high functional group tolerance.