Mechanistic Studies of Nucleophilic Organocatalysis by N-Heterocyclic Carbenes

大自然使用称为酶的复杂分子作为高度特异性的催化剂，用于生物过程所必需的多种化学转化。虽然酶反应是有效的，但通常需要另一种分子，称为辅因子，以促进特定的转化。为了加深我们对这些过程的理解，合成化学家们不断尝试设计具有模拟酶促转化能力的人工分子。目前人们对这一研究领域的一个特定分支，即通常所知的有机催化，有很大的兴趣。这种技术使用小的有机分子代替酶，以进行选择性的化学反应。该提案旨在从根本上了解一种特殊类型的简单有机分子（称为N-杂环卡宾）如何能够催化广泛的选择性化学转化。大自然使用卡宾等价物作为一系列化学转化的辅助因子，本提案旨在理解为什么它们可以在实验室中使用。通过了解特定过程中的每一步是如何工作的，以及通过了解每一步的速率如何随催化剂结构的变化而变化，我们希望能够为未来制备高选择性和高效的催化剂。

Nature uses complex molecules known as enzymes as highly specific catalysts for a multitude of chemical transformations that are essential for biological processes. Although efficient, enzyme reactions often need another molecule, known as a co-factor, to promote specific transformations. In order to further our understanding of these processes, synthetic chemists are constantly trying to engineer artificial molecules that have the ability to mimic enzymatic transformations. There is much current interest in one specific branch of this area of research, which is commonly known as organocatalysis . This technique uses small organic molecules instead of enzymes in order to carry out selective chemical reactions. This proposal aims to develop a fundamental understanding of how one particular class of a simple organic molecule, known as an N-heterocyclic carbene, is able to catalyse a wide range of selective chemical transformations. Nature uses a carbene equivalent as a co-factor in a range of chemical transformations and this proposal seeks to understand why they can be used in the laboratory. By understanding how each step in a particular process works, and by comprehending how the rate of each step changes with a change in catalyst structure, we hope to be able to prepare highly selective and efficient catalysts for the future.