PHOTOLYSIS OF TRIARYLMETHYLPHOSPHONIC ACIDS AND THEIR ESTERS

Upon UV-irradiation in an alkaline alcohol solution, some triarylmethylphosphonic acids underwent C-P bond cleavage to give triarylmethanes and alkyl dihydrogenphosphates, while, in an acidic or a neutral alcohol solution, they afforded biaryls. Their dimethyl esters gave also biaryls and dimethyl [alkoxy(aryl)methyl]phosphonates, which were derived from the insertion of (dialkoxyphosphinyl) arylcarbenes into the OH bond of the alcohol. The carbene was generated by photo-α,α-elimination of two aryl groups of the phosphonate.