The addition of hydrogen bromide to 1-bromocyclobutene, 1-bromocyclopentene and 1- bromocycloheptene under free radical conditions gives ratios of cis to trans isomers of the 1, 2-dibromocycloalkanes of 79: 21, 94: 6 and 91: 9, respectively. These isomers have been separated and characterized. An explanation of the variation in isomer ratios is given in terms of a balance between a mechanistic preference for a trans addition process and a ...
