Process for the preparation of stilbenedicarboxylate esters

Process for the preparation of dimethyl 4,4'-stilbenedicarboxylate from methyl p-formylbenzoate by the steps comprising:

• (1) preparing methyl p-(hydroxymethyl)benzoate by hydrogenating methyl p-formylbenzoate at a temperature of about 60.degree. to 75.degree. C. and a pressure of about 40 to 60 bars absolute in the presence of a nickel hydrogenation catalyst selected from Raney nickel and supported nickel catalysts and an inert solvent;
• (2) contacting the methyl p-(hydroxymethyl)benzoate of step (1) with triethyl phosphite to obtain diethyl p-(methoxycarbonyl)benzyl phosphite;
• (3) contacting the phosphite ester of step (2) with a catalytic amount of iodine at a temperature of about 120.degree. to 180.degree. C. in the presence of an inert solvent to rearrange the phosphite ester to diethyl p-(methoxycarbonyl)benzylphosphonate;
• and
• (4) contacting the phosphonate compound of step (3) with methyl p-formylbenzoate at a temperature of about 25.degree. to 35.degree. C. in the presence of an alkali metal alkoxide and an inert solvent to obtain dimethyl 4,4'-stilbenedicarboxylate.