Methods for the preparation of bromomethylenecycloalkanes are described. The application of the Wittig reaction is shown to involve appreciable abstraction of bromine as well as hydrogen from bromomethyltriphenylphosphonium bromide to produce ultimately a mixture of methylenecycloalkane and bromomethylenecycloalkane. The decarboxylative debromination of a-bromo-1-bromocycloalkylacetic acids is shown to give high yields of ...