Abstract: A cis-bicyclo[4.3.0]non-2-ene derivative of the formula: ##STR1## wherein R is a hydrogen atom, or a protecting group for a hydroxyl group, R.sup.1 is a hydrogen atom, A C.sub.1 -C.sub.12 straight or branched chain alkyl group, a substituted or unsubstituted phenyl group, a C.sub.6 -C.sub.12 aralkyl group containing a condensed aromatic ring or an aromatic hetero ring, or 1 equivalent of a cation, A is --CH.dbd.CH--CH.sub.2 --, or --CH.sub.2 --CH.sub.2 --O--, R.sup.2 is a C.sub.3 -C.sub.10 straight or branched chain alkyl group, a C.sub.1 -C.sub.3 alkyl group substituted by an aryloxy group which may be substituted, a C.sub.3 -C.sub.12 straight or branched chain alkenyl group, a C.sub.3 -C.sub.8 straight or branched chain alkynyl group, a C.sub.1 -C.sub.3 alkyl group substituted by a phenyl or phenoxy group which may be substituted, by a C.sub.1 -C.sub.6 alkoxy group or by a C.sub.5 -C.sub.8 cycloalkyl group, R.sup.3 is a hydrogen atom, a methyl group, or a vinyl group, and X is a halogen atom.