Mechanistic Investigation of the 2,5-Diphenylpyrrolidine-Catalyzed Enantioselective α-Chlorination of Aldehydes
作者:Nis Halland、Mette Alstrup Lie、Anne Kjærsgaard、Mauro Marigo、Birgit Schiøtt、Karl Anker Jørgensen
DOI:10.1002/chem.200500776
日期:2005.11.18
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
通过实验和计算方法,研究了2,5-二苯基吡咯烷催化醛与亲电子卤化试剂的对映选择性α-氯化反应的机理。这些研究使我们提出了一种反应机理,该反应机理是通过手性催化剂-底物配合物的初始N-氯化反应,然后是氯原子向烯胺碳原子的1,3-σ转移。所建议的反应过程与先前提出的有机催化烯胺反应机理不同,在后者中,碳-亲电子键是直接形成的。此外,确定了整个反应中确定速率的步骤,并探讨了非线性效应的存在。