Voloshkin Vladislav A, Villa Marco, Martynova Ekaterina A, Beliš Marek, Van Hecke Kristof, Ceroni Paola, Nolan Steven P
Department of Chemistry, Centre for Sustainable Chemistry, Ghent University Krijgslaan 281, S-3 9000 Ghent Belgium
Department of Chemistry "Giacomo Ciamician", Center for Chemical Catalysis-C3, University of Bologna Via Selmi, 2 40126 Bologna Italy
Chem Sci. 2024 Feb 21;15(12):4571-4580. doi: 10.1039/d3sc06675d. eCollection 2024 Mar 20.
Energy transfer (EnT) photocatalysis has emerged as a valuable tool for constructing complex organic scaffolds [2 + 2]-cycloaddition reactions. Herein, we present the use of [Au(SIPr)(Cbz)] as a sensitizer for the [2 + 2]-cycloaddition of coumarins and unactivated alkenes. Widely used in EnT catalysis, iridium and organic sensitizers proved less efficient under the examined catalytic conditions. The developed protocol permits the synthesis of cyclobutane-fused chromanones from readily available starting materials. A wide range of alkenes and substituted coumarins, including naturally occurring compounds, were reacted under mild conditions leading to structurally complex products with good functional group tolerance. Mechanistic studies reveal a previously overlooked reaction pathway for energy transfer catalysis involving coumarins.
能量转移（EnT）光催化已成为构建复杂有机骨架[2 + 2]环加成反应的一种有价值的工具。在此，我们展示了使用[Au(SIPr)(Cbz)]作为香豆素与未活化烯烃[2 + 2]环加成反应的敏化剂。铱和有机敏化剂在EnT催化中广泛使用，但在所研究的催化条件下效率较低。所开发的方法允许从容易获得的起始原料合成环丁烷稠合的色满酮。各种烯烃和取代香豆素，包括天然存在的化合物，在温和条件下反应，生成具有良好官能团耐受性的结构复杂的产物。机理研究揭示了涉及香豆素的能量转移催化中一个以前被忽视的反应途径。
