Aspects of organic synthesis using phosphorus derivatives

Part 1. A mild, one-stage process has been developed for the preparation of primary and secondary alkyl chlorides by the reaction of the corresponding alcohols with phosphororus trisdimethylamide and carbon tetrachloride. In particular in this work the stability of common sugar protecting groups towards the reagent was examined. A number of model compounds containing acetal, ether or ester groups in addition to free hydroxyl group were examined. They were found to undergo a smooth conversion of hydroxyl to halide with no effect on other groups in the molecule. This rapid, high yield reaction proceeds with inversion of configuration and without evidence of isomerisation. The mechanism of the reaction and its extension to include other polyhalogenated hydrocarbons are discussed. For example by using bromoform or carbon tetrabromide the method has been extended to the synthesis of alkyl bromides. Part 2. The reaction of tertiary phosphine oxide anions with carbonyl compounds discovered by Horner et al. has been used in attempts to extend it for the preparation of phosphinic acids especially unsymmetrical phosphinic acids. The method was found to be of limited application