Читать книгу Catalytic Asymmetric Synthesis - Группа авторов - Страница 84

Over the past two decades, the development of enantioselective reactions under asymmetric Brønsted base catalysis has been intensively explored, and fruitful progress has been made in this field. A variety of useful enantioselective transformations has been achieved based on the rational reaction design as well as the suitable choice of a chiral catalyst. In parallel with the development of new enantioselective reactions, various types of efficient chiral uncharged organobase catalysts have been designed and synthesized, which dramatically accelerated the progress. In particular, the new types of chiral organosuperbase catalysts possessing much higher basicity than that of conventional chiral tertiary amine catalysts have substantially expanded the scope of applicable pronucleophiles. Nevertheless, there is still a large room for improvement in this field. For instance, the development of chiral organosuperbase catalysts is still in its infancy, and the development of new catalysts, particularly with unprecedented catalyst design, is highly desirable to accomplish a variety of enantioselective transformations using a much broader range of pronucleophiles. On the other hand, the mechanism and the origin of the stereoselectivity have not been clarified in many reactions. Therefore, detailed mechanistic studies are also needed for a better understanding of the catalysis and the development of next generation of chiral catalysts and reaction systems. Further progress of the asymmetric Brønsted base catalysis is highly anticipated, which will find valuable applications in various fields of organic chemistry, such as natural product synthesis and drug discovery research.