Process for preparing unsaturated spiranic derivatives of formula ##STR1## wherein index n represents integer 1 or 2 and wherein symbol R defines a lower alkyl radical, starting from the corresponding cycloalkanone via an addition thereto of a dihalo-alkene of formula ##STR2## wherein symbol R possesses the above-indicated meaning and X represents a halogen atom.
从相应的环烷酮出发,通过加入式为##STR2##的二卤代烯烃,其中符号R具有上述意义,X表示卤素原子,制备式为##STR1##的不饱和螺环衍
生物的过程,其中指数n表示整数1或2,符号R定义为较低的烷基基团。