生命科学学院知识库

当一个碳原子与四个具有不同取代基的碳原子或碳官能团相连，就形成了全碳季碳手性中心，其广泛存在于天然产物和具有生物活性的化合物中，也是许多药物分子的重要组成部分及活性单元，所以通过不对称的方法构建全碳季碳手性中心一直是有机合成化学感兴趣的课题。具有全碳季碳手性中心的环内酯化合物同样表现出独特的生物活性，是许多生物活性物质不可或缺的重要骨架，同时也能够作为一些生物活性物质的合成前体。通过不对称催化的方式，如何高效绿色
地合成包含全碳季碳手性中心的环内酯化合物具有重要的应用价值，并且是一项持久的具有挑战性的工作。以 2-酰基环戊内酯为底物，通过不对称共轭加成来合成具有全碳季碳手性中心环内酯化合物的研究迄今尚未报道，本文首次通过有机催化的 2-酰基环戊内酯对乙烯基芳香酮的不对称共轭加成反应，合成了含手性全碳季碳的环戊内酯类化合物。
不对称催化的共轭加成反应是构建全碳季碳手性中心的重要策略之一。本文主要通过合成一系列双功能的手性叔胺-硫脲或方酰胺催化剂，高效催化 2-酰基环戊内酯化合物与简单易得的乙烯基酮之间的直接不对称共轭加成反应，以良好的产率，高对映选择性得到具有 2-位全碳季碳手性中心的 2-酰基环内酯化合物。这为 2-酰基环内酯参与不对称共轭加成反应来构筑全碳季碳手性中心提供了切实可行的方法。该催化反应条件温和，可操作性强，具有一定的应用潜力。

When a carbon atom is connected to four carbon atoms or carbon functional groups with different substituents, an all-carbon quaternary chiral center is formed, which is widely present in natural products and biologically active compounds and is also important components and active units of many drug molecules. Therefore, the asymmetrical construction of all-carbon quaternary centers has always been an interesting topic of organic synthetic chemistry. The lactone compounds containing the all-carbon quaternary center exhibit unique biological activities and are indispensable frameworks for many biologically active substances, and are also synthetic precursors for some biologically active substances. How to efficiently synthesize the lactone compounds with an all-carbon quaternary chiral center through asymmetric catalysis is a
long-lasting and challenging work, which has important applicable value. It has not been reported so far that the synthesis of chiral center cyclic lactone compounds with all-carbon quaternary centers by asymmetric conjugate addition using 2-acylcyclopentanolactone as the substrate. In this paper, cyclopentanolactones containing chiral all-carbon quaternary centers have been synthesized firstly by organocatalytic asymmetric conjugate addition of 2-acylcyclopentanolactones to vinyl aromatic ketones.
Asymmetric catalyzed conjugate addition is one of the most important methods for synthesis of the all-carbon quaternary center. In this paper, direct asymmetric conjugate additions between 2-acyl-lactones and readily available vinyl ketones are efficiently catalyzed by a series of bifunctional chiral thiourea or amide catalysts to obtain the 2-acyl lactone compounds with a 2-position all-carbon quaternary stereocenter in high enantioselectivity and excellent yield. This provides a practical method for the construction of chiral all-carbon quaternary centers by 2-acyl-cyclolactones through asymmetric conjugate addition. The catalytic reaction are well in mild reaction conditions, easy to operate, and thus has important applicable potential.