biostudies-literatureCelebi-Olcum NFIC NIH HHSNIGMS NIH HHS6944-52https://www.ebi.ac.uk/biostudies/studies/S-EPMC2748823biostudies-literatureUnknown74(18)Density functional theory calculations were used to investigate the [3,3]- and [1,3]-shifts of O-allylic trichloroacetimidates in the presence of cinchona alkaloids. Thermal [1,3]- and [3,3]-rearrangements proceed through concerted pseudopericyclic transition states to give the corresponding rearranged products. [1,3]-Rearrangement is catalyzed via a double S(N)2' mechanism in which syn addition of the nucleophile is exclusively preferred in both steps. The catalyzed mechanism is favored by a 6.3 kcal/mol free energy difference compared to the alternative [3,3]-rearrangement pathway. The fast-reacting enantiomer is predicted to be determined by the availability of the H-bonding interaction between the catalyst and the substrate.The Journal of organic chemistryMechanism and selectivity of cinchona alkaloid catalyzed [1,3]-shifts of allylic trichloroacetimidates.PMC2748823R03TW007177R03 TW001318-03R03 TW007177GM36700R01 GM036700-24R37 GM036700R01 GM036700Aviyente VHouk KNCelebi-Olcum NfalseMechanism and selectivity of cinchona alkaloid catalyzed [1,3]-shifts of allylic trichloroacetimidates.Density functional theory calculations were used to investigate the [3,3]- and [1,3]-shifts of O-allylic trichloroacetimidates in the presence of cinchona alkaloids. Thermal [1,3]- and [3,3]-rearrangements proceed through concerted pseudopericyclic transition states to give the corresponding rearranged products. [1,3]-Rearrangement is catalyzed via a double S(N)2' mechanism in which syn addition of the nucleophile is exclusively preferred in both steps. The catalyzed mechanism is favored by a 6.3 kcal/mol free energy difference compared to the alternative [3,3]-rearrangement pathway. The fast-reacting enantiomer is predicted to be determined by the availability of the H-bonding interaction between the catalyst and the substrate.2009-01-01T00:00:00Z2009 Sep2024-12-03T20:38:10.828Z2019-03-27T00:25:12ZS-EPMC27488231968914710.1021/jo901109s