In recent years, visible light-induced reactions of diazo compounds have attracted increasing attention in organic synthesis, leading to improvement of existing reactions, as well as to the discovery of unprecedented transformations. Thus, photochemical or photocatalytic generation of both carbenes and radicals provide milder tools toward these key intermediates for many valuable transformations. However, the vast majority of the transformations represent new reactivity modes of diazo compounds, which are achieved by the photochemical decomposition of diazo compounds and photoredox catalysis. In particular, the use of a redox-active photocatalysts opens the avenue to a plethora of radical reactions. The application of these methods to diazo compounds led to discovery of transformations inaccessible by the classical reactivity associated with carbenes and metal carbenes. In most cases, diazo compounds act as radical sources but can also serve as radical acceptors. Importantly, the described processes operate under mild, practical conditions. This Review describes this subfield of diazo compound chemistry, particularly focusing on recent advancements.

中文翻译：

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重氮化合物及其前体的可见光诱导反应


近年来，重氮化合物的可见光诱导反应在有机合成中引起了越来越多的关注，导致现有反应的改进，以及前所未有的转变的发现。因此，卡宾和自由基的光化学或光催化生成为这些关键中间体的许多有价值的转化提供了更温和的工具。然而，绝大多数转化代表了重氮化合物的新反应模式，这些转化是通过重氮化合物的光化学分解和光氧化还原催化来实现的。特别是，氧化还原活性光催化剂的使用为大量自由基反应开辟了途径。将这些方法应用于重氮化合物导致发现了与卡宾和金属卡宾相关的经典反应性无法实现的转化。在大多数情况下，重氮化合物充当自由基源，但也可以充当自由基受体。重要的是，所描述的过程在温和、实用的条件下进行。这篇综述描述了重氮化合物化学的这个子领域，特别关注最新的进展。