process for preparation of cyclopropane carboxylic acid derivatives bearing an aldehyde function

摘要

A process for the preparation of cyclopropane carboxylic acid derivatives of the formula IMAGE I wherein Z is selected from the group consisting of -CN, -COOH and -COOR1, R1 is alkyl of 1 to 6 carbon atoms and R2 and R3 are alkyl of 1 to 4 carbon atoms or taken together with the carbon atom to which they are attached form a carbon homocycle of 3 to 6 carbon atoms comprising reacting at low temperatures in a solvent in the presence of a strong base a compound of the formula IMAGE II wherein Z has the above definitions and R is alkyl of 1 to 6 carbon atoms or together form a polymethylene of 2 to 3 carbon atoms with a sulfone of the formula IMAGE III wherein R2 and R3 have the above definitions and Y is an aromatic group followed by aqueous treatment to obtain a compound of the formula IMAGE IV wherein Y, R, R2, R3 and Z have the above definitions, reacting the latter at a low temperature in a solvent with a strong base while letting the temperature rise to obtain a compound of the formula IMAGE V wherein R, R2, R3 and Z have the above definitions of the cis/trans configuration richer in the trans isomer and either reacting the latter when Z is -CN or -COOR1 with a strong base in an aqueous media followed by acidification to obtain a compound of the formula IMAGE Va wherein R, R2 and R3 have the above definitions having the same configuration as the compound of formula V or reacting the compound of formula V or Va with an acid agent in an aqueous media to obtain the corresponding compound of formula I with the same configuration as the compound of formula V or Va and optionally treating the latter with a weak base at room temperature to obtain the compound of formula I with a trans configuration which are valuable intermediates for the preparation of esters of cyclopropane carboxylic acid having elevated insecticidal activity.