Preparation of α-cyanobenzyl esters

Claim 1

A process for the preparation of an α-cyanobenzyl ester having the formula I ##STR4## wherein A is (a) a cyclopropyl group of formula II ##STR5## wherein R a and R b each is an alkyl group having from 1 to 6 carbon atoms, a halogen atom having an atomic number of from 9 to 35, inclusive or when R a is a hydrogen atom then R b is an alkenyl group having from 2 to 6 carbon atoms optionally substituted by from 1 to 3 fluorine, chlorine and/or bromine atoms; R c and R d each is an alkyl group having from 1 to 6 carbon atoms or when R c is a hydrogen atom then R d is an alkenyl group having 1 to 6 carbon atoms optionally substituted by from 1 to 3 fluorine, chlorine and/or bromine atoms, or at least one of R a and R b together or R c and R d together is an alkylene group having 2 to 6 carbon atoms or (b) an optionally substituted aralkyl group of the formula III ##STR6## wherein R 3 is an alkyl, cycloalkyl or alkenyl group containing up to 4 carbon atoms and R 1 is a hydrogen atom, a halogen atom having an atomic number of from 9 to 53, inclusive, NO 2 , CF 3 , an alkyl group containing from 1 to 4 carbon atoms, and alkoxy group containing from 1 to 2 carbon atoms, an allyl group or a propargyl group and R 2 is a hydrogen atom or a methyl group; X is an alkyl, alkenyl, aralkyl or aryloxy group containing up to 10 carbon atoms; and n is an integar of from 1 to 3; which comprises contacting a carboxylic acid halide with a benzaldehyde cyanohydrin in the presence of a Lewis acid catalyst.