可见光诱导的钯催化Heck反应

Visible Light-Induced Pd-Catalyzed Heck Reactions

Heck反应作为构建C—C键最为强大和实用的合成工具之一, 经过数十年的发展已逐渐趋于成熟, 并在各种功能分子的合成中获得了极为广泛的应用. 近年来, 随着光催化的兴起, 可见光诱导的钯催化Heck反应也随之快速发展起来. 作为一种新颖的C—C键构建策略, 可见光诱导的Heck反应极大地扩展了底物的适用范围, 包括亲核试剂和亲电试剂. 同时, 这种由激发态钯络合物引发, 机理上涉及杂化的自由基-PdⅠ物种的特殊反应路径也使得可见光诱导的钯催化Heck反应表现出条件温和、官能团兼容性好以及转化多样性等特点, 是对经典Heck反应的极大补充, 在功能分子的合成以及复杂化合物的后期修饰等方面极具应用潜力. 根据反应亲核/亲电试剂种类, 以及串联反应类型, 对可见光诱导的Heck反应进行归类和总结, 并对部分反应机理进行了简要阐述.

Heck reaction is regarded as one of the most powerful and practical synthetic tools to construct C—C bonds, and has gained increasingly widespread applications in the synthesis of various functional molecules over the past decades. As an emerging strategy for the formation of C—C bonds, visible light-induced Pd-catalyzed Heck reaction has tremendously extended the scope of substrates, in both aspects of nucleophiles and electrophiles. This unique transformation, triggered by photoexcited Pd0 and mechanistically involving hybrid radical-PdⅠ species, features mild conditions, excellent functional compatibility and transformational diversity, which greatly complements classical Heck reaction catalyzed by ground-state Pd complexes. These advantages will render visible light-induced Heck reaction widespread applications in the synthesis of functional molecules and late-stage modification of structurally complex compounds. According to the species of nucleophiles/ electrophiles and types of cascade reactions, visible light-induced Heck reactions are logically classified, and some of the elusive reaction mechanisms are also illustrated.