The rearrangement of allyl, n-crotyl, and isocrotyl diphenylacetates to the respective cy- substituted diphenylacetic acids by means of mesitylmagnesium bromide or sodium hydride has recently been reported.'This reaction has now been extended to allyl 9- fluorenecarboxylate. 9-Fluorenecarboxylic acid was prepared from benzilic acid and aluminum chloride by a modification of the method previously described. This modified ...