Light-Mediated Organocatalysis with N-Heterocyclic Carbenes

本项目主要研究光辐射对N-杂环卡宾（NHC）催化有机反应的影响。NHC-有机催化已经成为一种强有力的工具，它促进了许多重要的合成和通常的对映选择性转化，包括醛衍生物的umpolung反应。尽管近年来取得了很大的进展，但可获得的反应途径的范围在很大程度上仍然限于经典的醛醇型过程，并且高度寻求涉及不同的非经典途径的新策略，以增强这种化学的范围。受NHC稳定开壳物种的能力的启发，我们打算研究光照射对NHC催化的羰基化合物反应的影响，主要集中在羧酸和酯底物上。该项目涉及一个新的催化概念，涉及光介导的激发酰基唑中间体，允许经典的光化学反应，通常进行酮使用以前不合适的羧酸衍生物底物进行。这一概念的新的催化应用将被开发，而化学计量的研究，包括光谱和实验研究将被用来提供机理的见解和指导反应的发展。

This project is focused on investigating the effect of light irradiation on organic reactions catalysed by N-heterocyclic carbenes (NHCs). NHC-Organocatalysis has emerged as a powerful tool that facilitates many synthetically important and often enantioselective transformations including umpolung reactions of aldehyde derivatives. Despite the great advances made in recent years, the range of accessible reaction pathways remains largely limited to classical aldol-type processes and new strategies involving different, non-classical pathways that enhance the scope of this chemistry are highly sought. Inspired by the previously-noted ability of NHCs to stabilise open-shell species, we intend to study the effect of light irradiation on NHC-catalyzed reactions of carbonyl compounds, focusing mostly on carboxylic acid and ester substrates. The project concerns a new catalysis concept involving light-mediated excitation of acyl azolium intermediates that allows classical photochemical reactions conventionally performed on ketones to be conducted using previously unsuitable carboxylic acid derivative substrates. New catalytic applications of this concept will be developed while stoichiometric studies including spectroscopic and experimental investigations will be used to provide mechanistic insight and guide reaction development.