Synthesis of substituted dibenzophospholes. Part 3. Synthesis of 4,6-diaryldibenzophospholes from m-quaterphenyls

Some observations on T. Cohen's method for coupling 2-iodonitrobenzenes to 2,2′-dinitrobiphenyls are reported. A general method for making 2′,2″-di-iodo-m-quaterphenyls from the 2′,2″-diamines, reported in Part 2, features decomposition of the bis-diazonium iodomercurates to dibenziodolium iodomercurates and pyrolysis of the latter. The procedure can be used to prepare other aryl iodides. 2′,2″-Di-iodo-m-quaterphenyls, on successive treatment with butyl-lithium, phosphorus trichloride, water, and hydrogen peroxide, yield 4,6-diaryl-5-hydroxydibenzophosphole 5-oxides, three of which were prepared. The structures of two derivatives of these, 2,8-dichloro-3,7-di-(2-hydroxyethoxy)-5-methoxy-4,6-diphenyldibenzophosphole 5-oxide and 5-hydroxy-3,7-dimethoxy-4,6-di(4-methoxy-3,5-di-t-butylphenyl)dibenzophosphole 5-oxide, have been determined by X-ray crystallography and are reported in the Appendix.