Method for producing (bromomethyl)cyclopropane and (bromomethyl)cyclobutane

Method for preparing a compound (A) of the following formula:

• in which R is a cyclobutane or cyclopropane group, comprising the following steps:
• a) solubilizing a triarylphosphite in a polar aprotic solvent,
• b) adding a bromine compound at a temperature of less than 15° C.,
• c) lowering the temperature to less than 0° C. after completion of the reaction of the bromine with the triarylphosphite,
• d) adding cyclobutylmethanol or cyclopropylmethanol at a temperature of less than 0° C.,
• e) recovering the compound (A).