Light-Mediated Organocatalysis with N-Heterocyclic Carbenes

本项目主要研究光照对n -杂环碳烯（NHCs）催化有机反应的影响。nhc -有机催化已经成为一种强大的工具，促进了许多合成上重要的和经常对映选择性转化，包括醛衍生物的非polung反应。尽管近年来取得了巨大的进步，但可访问的反应途径的范围仍然很大程度上局限于经典的aldoltype过程，并且高度寻求涉及不同的新策略，非经典途径，以增强这种化学的范围。受之前提到的NHCs稳定开壳物质的能力的启发，我们打算研究光照射对NHCs催化羰基化合物反应的影响，主要集中在羧酸和酯底物上。该项目涉及一种新的催化概念，涉及酰基唑中间体的光介导激发，允许传统上在酮上进行的经典光化学反应使用以前不合适的羧酸衍生物底物进行。这一概念的新催化应用将得到发展，而化学计量学研究包括光谱和实验研究将用于提供机理见解和指导反应发展。

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.