Mechanistic investigation of the 2,5-diphenylpyrrolidine-catalyzed enantioselective alpha-chlorination of aldehydes |
| |
| Authors: | Halland Nis Alstrup Lie Mette Kjaersgaard Anne Marigo Mauro Schiøtt Birgit Jørgensen Karl Anker |
| |
| Institution: | Danish National Research Foundation, Center for Catalysis, Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark. |
| |
| Abstract: | The mechanism for the 2,5-diphenylpyrrolidine-catalyzed enantioselective alpha-chlorination of aldehydes with electrophilic halogenation reagents has been investigated by using experimental and computational methods. These studies have led us to propose a mechanism for the reaction that proceeds through an initial N-chlorination of the chiral catalyst-substrate complex, followed by a 1,3-sigmatropic shift of the chlorine atom to the enamine carbon atom. The suggested reaction course is different from previously proposed mechanisms for organocatalytic enamine reactions, in which the carbon-electrophile bond is formed directly. Furthermore, the rate-determining step in the overall reaction was determined and the presence of nonlinear effects was probed. |
| |
| Keywords: | asymmetric catalysis chlorination density functional calculations isotope effects kinetics sigmatropic rearrangement |
| 本文献已被 PubMed 等数据库收录！ |
|
