γγ-Disubstituted itaconic acids. Part VI. The stobbe condensation of aryl cyclohexyl ketones and o-methylbenzophenone with dimethyl succinate

Abstract

The condensation of cyclohexyl-phenyl, and cyclohexyl-p-tolyl ketones with dimethyl succinate in the presence of potassium t-butoxide, gave predominantly the trans-(Ar/CO₂Me)-half esters (1) and (2), which were cyclised to naphthalene derivatives. The cis-(Ar/CO₂Me)-half ester (11) which predominated in the case of p-chlorophenyl cyclohexyl ketone, was converted via the anhydride into the oxo-indenyl acid (10).

o-Methylbenzophenone, when similarly condensed with dimethyl succinate, gave a mixture of cis-(Ph/CO₂Me) and trans-3-methoxycarbonyl-4-phenyl-4-o-tolyl-but-3-enoic acid in which the former half ester is present in a slightly greater proportion. Their configuration was established by converting them into 1-phenylnaphthalene derivatives.