PROCESS FOR PREPARATION OF LOWER ALKYLESTERS OF ACID 3-(2- -CHLORINE-3,3,3-TRIFLUOROPROP-1-ENE-1-YL)-2,2- -DIMETHYLCYCLOPROPANE-CARBOXYL AND INTERMEDIATE PRODUCTS OF THIS PROCESS

A process for the preparation of a lower alkyl ester of 3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)- 2,2-dimethylcyclopropane carboxylic acid where lower alkyl means alkyl of up to four carbon atoms which comprises the steps of (a) reacting a compound of formula: CF3-CXCl-CH(OH)-CH=C(CH3)2 wherein X is chloro or bromo, with a tri-lower-alkyl orthoacetate containing up to four carbon atoms in each alkyl group in the presence of at least a catalytic amount of an active clay at an elevated temperature for a sufficient time to obtain a compound of formula: CF3-CXCl-CH=CH-C(CH3)2-CH2CO2R wherein R is an alkyl group containing up to four carbon atoms, and (b) treating said compound of formula (III) with at least one molar equivalent of a base to obtain said alkyl ester of 3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropane carboxylic acid.