Work

Mechanism and Selectivity of Cinchona Alkaloid Catalyzed [1,3]-Shifts of Allylic Trichloroacetimidates

Year: 2009

Type: article

Abstract: 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.

Source: The Journal of Organic Chemistry

DOI: 10.1021/jo901109s

Authors: Nihan Çelebi-Ölçüm, Viktorya Aviyente, K. N. Houk

Institutions: Boğaziçi University, University of California, Los Angeles

Language: English

Topic: Asymmetric Synthesis and Catalysis

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: National Institutes of Health, National Institute of General Medical Sciences, Fogarty International Center