Potassium tert-butoxide (8.42 g., 0.075 mole) dissolved in tert-butanol (450 ml.) is added to a refluxing solution of 2-methyl-5-benzyloxy-6,7-dichloro-1-indanone (16.1 g., 0.05 mole) in tert-butanol (150 ml.)-benzene (600 ml.), refluxing is continued for 2.5 hrs., then 4,4'-dimethoxydiphenyliodonium chloride (37.66 g., 0.10 mole) is added and refluxing is continued for 3 hrs. The reaction mixture is cooled to 25° C., 500 ml. water added, and the mixture concentrated in vacuo to give a brown oil which on ether extraction, drying over anhydrous magnesium sulfate, removal of the ether and chromatographing of the residue on silica gel with chloroform gives 3.44 g. of 2-(4-methoxyphenyl)-2-methyl-5-benzyloxy-6,7-dichloro-1-indanone which melts at 115°-119° C. and is used without further purification.
