PROCESS FOR THE PREPARATION OF DI-(HALO)-VINYL COMPOUNDS

摘要

PROCESS FOR THE PREPARATION OF DI-(HALO)-VINYL COMPOUNDS A process for the preparation of a di-(halo)-vinyl compound, useful as an intermediate in the manufacture of pyrethroid insecticides, of the general formula: (I) wherein Hal represents a halogen atom and R1 an alkyl group or a substituted cyclopropyl group of the general formula: (II) wherein R2 represents a substituted or unsubstituted alkyl group, wherein (a) a tri(dialkylamino)phosphine or an alkyl ester of an ortho-phosphorus acid bis(dialkylamide) is reacted with a tetrahalomethano or a trihalomethane and (b) the product resulting from the first step is reacted uith an aldehyde of the general formula: (III) wherein R1 has the same meaning as in the general formula I, both steps being carried out in the presence of B substantially inert solvent.