(2,2-Disubstituted vinyl).gamma.-butyrolactones

Abstract

(2,2-Disubstituted vinyl)-.gamma.-butyrolactones of the formula: ##STR1## in which R.sub.1 and R.sub.2 are hydrogen or C.sub.1 -C.sub.6 alkyl, preferably methyl, R.sub.3 and R.sub.4 are hydrogen, C.sub.1 -C.sub.6 alkyl, preferably methyl, or halogen, or, together with the carbon atom to which they are attached, form a cycloalkyl group, and R.sub.5 is C.sub.1 -C.sub.6 alkyl, are prepared by condensing an epoxide of the formula: ##STR2## with a malonic acid ester of the formula: ##STR3## in a basic medium. The butyrolactones of formula I are valuable intermediates for the synthesis of synthetic pyrethroids having insecticidal activity.

Dependencies are inferred from the claim text.