Computational interpretations on 5-endo-trig cyclization of terminally difluorinated homoallylic alkoxides

Although 5-endo-trig cyclization reactions are generally recognized as a disfavored process according to the well-accepted Baldwin’s rules, we have already disclosed that the corresponding anionic version was expected to be smoothly carried out by entry of two fluorine atoms at the terminal carbon atom of substrates by computation of the model alkoxide derived from 4,4-difluorobut-3-en-1-ol 5b. In this article was described the further ab initio calculations for the cyclic alkoxide 8, closely resembled to our original molecules, which successfully revealed that such substitution at the reaction site caused the similar strong polarization and the resultant Coulombic attraction as well as the anomeric effect was considered to be one of the most important driving forces of the present reaction.