PREPARATION OF CYCLOPROPANE ESTERS

摘要

There is disclosed 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 which comprises the steps of (a) reacting a compound of the formula (I): CF3-CXC1-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 acid catalyst at an elevated temperature for a sufficient time to obtain a compound of the formula (III): CF3-CXC1-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. The products are useful as intermediates for insecticides.