The mass spectral fragmentation reactions of twenty-one 1,1-dichlorocyclopropanes prepared from various isomeric octenes are discussed. The most characteristic reaction may be represented as follows: The importance of this fragmentation and the distribution of the positive charge between the species produced is a function of the degree of branching in the molecule. The more highly branched isomers produce less characteristic fragmentation patterns. The identification of isomeric octenes from the fragmentation patterns of the corresponding 1,1-dichlorocyclopropanes is discussed.
