C2-Symmetric sulfur derivatives of 2, 2', 3, 3'-tetramethoxybiphenyl

--A practical route to prepare dithioether, thiophene and thiophene S-dioxide derivatives of 2,2,3,3-tetramethoxy-1,1- biphenyl 1 is described. Resolution of 6,6-bis(methylthio)-3,3-dimethoxy-[1,1-biphenyl]-2,2-diol 15 was achieved and its absolute configuration was assigned by X-ray analysis of the corresponding phosphorothioamidate diastereomer 18.