Walsh Patrick J
University of Pennsylvania, Department of Chemistry, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323.
Acc Chem Res. 2003 Oct;36(10):739-49. doi: 10.1021/ar0300219.
The catalytic asymmetric addition of alkyl groups to aldehydes is an important reaction in the enantioselective synthesis of secondary alcohols. This reaction can be catalyzed by zinc- or titanium-based catalysts. While the mechanism of the zinc/amino alcohol catalysts has received significant attention, the titanium-based catalysts have been less studied. This Account summarizes our mechanistic studies with bis(sulfonamide) and BINOL-derived titanium catalysts. It also describes our use of this reaction in the development of new approaches to asymmetric catalysis, including applications of diastereomeric catalysts and optimization of asymmetric catalysts with achiral and meso ligands.
醛的烷基催化不对称加成反应是仲醇对映选择性合成中的重要反应。该反应可由锌基或钛基催化剂催化。虽然锌/氨基醇催化剂的作用机理已受到广泛关注，但对钛基催化剂的研究较少。本综述总结了我们对双（磺酰胺）和联萘酚衍生钛催化剂的机理研究。还描述了我们如何利用该反应开发不对称催化的新方法，包括非对映体催化剂的应用以及使用非手性和内消旋配体对不对称催化剂进行优化。
