Ag-Mediated Radical Cyclization of 2-Alkynylthio(seleno)anisoles: Direct Synthesis of 3-Phosphinoylbenzothio(seleno)phenes.

A new method for the direct synthesis of 3-phosphinoylbenzothio(seleno)phenes has been achieved through an Ag-mediated radical addition-cyclization of 2-alkynylthio(seleno)anisoles with secondary phosphine oxides in good yields under mild conditions. In this single reaction, benzenethiophene or benzeneselenophene skeleton, C(sp2)-P and C(sp2)-S bonds can be constructed with the cleavage of the C(sp3)-S bond, highlighting the efficiency and step-economics of this protocol.