Roussel Uclaf

Jacques Prost-Marechal

Julien Warnant

Philippe Cosquer

Jean Tessier

A novel process for the preparation of .alpha.-cyano-3-phenoxy-benzyl alcohol comprising reacting a compound capable of generating CN.sup.- ions and a m-phenoxy benzaldehyde bisulfite of the formula ##STR1## in the presence of a solvent or mixture of solvents which alcohol is useful for preparing insecticidal esters of cyclopropane carboxylic acids with a dihalovinyl chain.

Preparation of .alpha.-cyano-3-phenoxy-benzyl alcohol

A process for the preparation of an ester of chiral (A) acid with a racemic (R,S) .alpha.-cyano-3-phenoxybenzyl alcohol (B) by reacting an ester of chiral (A) acid with .alpha.-cyano-3-phenoxybenzyl alcohol of the formula ##STR1## in its optically active (R) form or (S) form or a mixture of esters of said (R) alcohol and (S) alcohol in non-equimolecular proportions with a base selected from the group consisting of ammonia, primary, secondary and tertiary amines, quaternary ammonium compounds, liquid amines of high molecular weight and a catalytic amount of a strong base in at least one solvent for the starting esters and in which the ester of racemic alcohol is soluble and recovering from the resulting solution the ester of chiral (A) acid with racemic (R,S) alcohol.

Novel racemization process

The novel esters, (R) .alpha.-cyano-3-phenoxybenzyl 2,2-dimethyl-3R-(2,2-dichlorovinyl)-cyclopropane-1R-carboxylate and (S) .alpha.-cyano-3-phenoxybenzyl 2,2-dimethyl-3R-(2,2-dichlorovinyl)-cyclopropane-1R-carboxylate, having insecticidal properties.

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Paris, France

Jacques Prost-Marechal