PREPARATION OF 2-CYANOHEXANOIC ACID DERIVATIVES

摘要

A process for the preparation of 2-cyanohexanoic acid derivative having the general formula: wherein X and Y each represent a chlorine or bromine atom, each Hal represents a fluorine, chlorine or bromine atom and R<1> and R<2> each independently represent an alkyl group of one to four carbon atoms, which comprises reacting a pentenoic acid compound of the general formula: wherein R<1> and R<2> have the same meaning as in the general formula I, with a tetrahalomethane of the general formula: CHal2XY (III) wherein HaI, X and Y have the same meaning as in the general formula I, in the presence of a catalyst and a solvent for the reactants, characterized in that the catalyst is a transition metal in a divided state belonging to Groups VIB, VIIB or VIII of the Periodic Table of the Elements or a carbonyl of such a transition metal. The 2-cyanohexanoic acid derivatives are useful as intermediates in the manufacture of synthetic pyrethroids which are a group of very active insecticides.