| 摘要 |
A process for the production of a cyclopropane derivative having the grouping <FORM:0874776/IV (b)/1> in which X and Y are halogen atoms or aryl groups which may be substituted, e.g. by alkyl, aryl, halogen or ether groups (at least one of X and Y being halogen), or of one or more reaction products formed therefrom by spontaneous splitting off of a hydrogen halide accompanied by isomerisation, comprises reacting an unsaturated compound containing one or more >C=C< grouping with a salt derived from an acid of the formula hal.CXY.COOH, where hal is a halogen atom, under conditions in which the salt is decarboxylated and in a medium yielding no protons under the decarboxylating conditions. The unsaturated compound may be acyclic, carbocylic or heterocyclic other than compounds containing only aromatic double bonds, e.g. benzene, and may be substituted, e.g. by alkyl, aryl, halogen or ether groups. A list of suitable compounds is given. The salt used is preferably a metal, e.g. sodium or a quaternary ammonium salt of an acid such as trichloroacetic or phenyldichloroacetic acid and reaction may be effected by heating, e.g. at reflux, in a solvent such as dimethoxyethane or tetrahydrofuran. In examples sodium trichloroacetate is reacted with cyclohexane to give 7,7-dichlorobicyclo-[4,1,0]-heptane, with 1,3,5-cycloheptatriene to give 8,8-dichloro-bicyclo-[5,1,0]-octa-2,4-diene, with butadiene to give 1,1-dichloro-2-vinylcyclopropane and with allyl chloride to give 1,1-dichloro-2-chloromethylcyclopropane. Chlorobenzene may be obtained by spontaneous dehydrochlorination and isomerisation of 6,6-dichloro-bicyclo-[3,1,0]-hex-2-ene obtained from cyclopentadiene and sodium trichloracetate. |
