Chloro-substituted benzospiro cyclopropane carboxylic acid

A method for preparing a chloro-substituted cyclopropane carboxylic acid of the formula ##STR15## which comprises reacting a spirocyclopropanecarboxylic acid ester of the formula ##STR16## wherein R is C.sub.1 -C.sub.3 alkyl with a iodobenzene dichloride in the presence of an inert solvent at a temperature in the range of from about 20.degree. C. to about 30.degree. C. for a period of time sufficient to essentially complete the reaction and obtain the dichloro derivative ##STR17## dehydrohalogenating the dichloro derivative III with an alkali metal alkoxide in the presence of a solvent to obtain the ester ##STR18## hydrolyzing the ester IV with a base to yield the acid I.