2,2-dimethyl-3-(but-1-en-3-ynyl)-cyclopropane carboxylates

A compound of the formula ##STR14## in all possible stereoisomeric forms and mixtures thereof wherein X is selected from the group consisting of hydrogen, halogen and alkyl, alkenyl, alkynyl and cycloalkyl, all having up to 8 carbon atoms and optionally substituted with at least one halogen, Y is selected from the group consisting of a) hydrogen, alkyl, alkenyl, alkynyl and cycloalkyl all having up to 8 carbon atoms optionally substituted iwth at least one member of the group consisting of halogen, --CN, --OH and alkoxy of 1 to 6 carbon atoms, b) phenyl and phenylalkyl of up to 16 carbon atoms optionally substituted with at least one member of the group consisiting of halogen, alkyl of 1 to 8 carbon atoms, alkoxy of 1 to 8 carbon atoms, --(CH.sub.2).sub.m --Si(Alk.sub.1).sub.3, --(CH.sub.2).sub.n --OAlk.sub.2, --(CH.sub.2).sub.p --SAlk.sub.3, halogen and hydrogen, m, n and p are integers from 0 to 6, Alk.sub.1, Alk.sub.2 and Alk.sub.3 being alkyl or cycloalkyl of up to 8 carbon atoms and R is ##STR15## wherein Z is selected from the group conssiting of hydrogen, fluorine, NH.sub.2, cycloalkyl, alkyl, alkenyl, alkynyl, O-alkyl, O-alkenyl, S-alkyl or S-alkenyl of up to 8 carbon atoms all optionally substituted by at least one halogen.