Ab Initio Investigations of the Rearrangements of some -Haloalkoxides to Epoxides via G3 Calculations

Abstract

The conformational analysis of five b-chloro- and b-bromo-alkoxides had been done. The minima and the conformational transition states were determined. The anti conformer was found to be the most stable one. Its percentage is more than 99. α-Methylation increases the nuclophilicity of oxygen .Consequently, it enhances the rate of the ring closure. In contrast to b- methylation which retards the rate of the ring closure. This observation could be attributed to the reactivity of alkyl halides in SN² reactions. The rearrangements of g and g^- conformers to carbonyl compounds are not feasible. Therefore, the main rearrangement that takes place in b-haloalkoxides is the formation of epoxides.