Franceschi Pietro, Cuadros Sara, Goti Giulio, Dell'Amico Luca
Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.
Angew Chem Int Ed Engl. 2023 Feb 13;62(8):e202217210. doi: 10.1002/anie.202217210. Epub 2023 Jan 12.
The synthesis of four membered heterocycles usually requires multi-step procedures and prefunctionalized reactants. A straightforward alternative is the photochemical [2+2]-heterocycloaddition between an alkene and a carbonyl derivative, conventionally based on the photoexcitation of this latter. However, this approach is limited by the absorption profile of the carbonyl, requiring in most of the cases the use of high-energy UV-light, that often results in undesired side reactions and/or the degradation of the reaction components. The development of new and milder visible light-driven [2+2]-heterocycloadditions is, therefore, highly desirable. In this Review, we highlight the most relevant achievements in the development of [2+2]-heterocycloadditions promoted by visible light, with a particular emphasis on the involved reaction mechanisms. The open challenges will also be discussed, suggesting new possible evolutions, and stimulating new methodological developments in the field.
四元杂环的合成通常需要多步程序和预官能团化的反应物。一种直接的替代方法是烯烃与羰基衍生物之间的光化学[2+2]杂环加成反应，传统上是基于后者的光激发。然而，这种方法受到羰基吸收光谱的限制，在大多数情况下需要使用高能紫外光，这常常导致不期望的副反应和/或反应组分的降解。因此，开发新的、更温和的可见光驱动的[2+2]杂环加成反应是非常必要的。在本综述中，我们重点介绍了可见光促进的[2+2]杂环加成反应开发中的最相关成果，特别强调了所涉及的反应机理。还将讨论面临的开放挑战，提出新的可能发展方向，并激发该领域新的方法学发展。
