Abstract: A three-step process for the production of chrysanthemic acid esters and their homologues of the formula: ##STR1## in which R.sub.1 and R.sub.2 are hydrogen or C.sub.1 -C.sub.6 alkyl,R.sub.3 and R.sub.4 are C.sub.1 -C.sub.6 alkyl or halogen or, together with the C atom to which they are attached, form a cycloalkyl group, andR.sub.5 is C.sub.1 -C.sub.6 alkyl,Which comprises:(1) decarboxylating a lactone of the formula: ##STR2## (2) treating the resulting decarboxylated lactone to effect ring cleavage, halogenation and esterification to form an ester of the formula: ##STR3## in which X is Cl, Br or I, and (3) TREATING THE ESTER X with a base to effect internal condensation whereby the desired product of formula I is obtained.The esters I are valuable intermediates for the preparation of synthetic pyrethroids having insecticidal activity.