A Redox Strategy for Light-Driven, Out-of-Equilibrium Isomerizations and Application to Catalytic C–C Bond Cleavage Reactions
作者:Eisuke Ota、Huaiju Wang、Nils Lennart Frye、Robert R. Knowles
DOI:10.1021/jacs.8b12552
日期:2019.1.30
We report a general protocol for the light-driven isomerization of cyclic aliphatic alcohols to linear carbonyl compounds. These reactions proceed via proton-coupled electron-transfer activation of alcohol O-H bonds followed by subsequent C-C β-scission of the resulting alkoxy radical intermediates. In many cases, these redox-neutral isomerizations proceed in opposition to a significant energetic gradient
我们报告了光驱动的环状脂肪醇异构化为线性羰基化合物的通用协议。这些反应通过醇 OH 键的质子耦合电子转移活化进行,随后生成的烷氧基自由基中间体的 CC β 断裂。在许多情况下,这些氧化还原中性异构化与显着的能量梯度相反,产生的产品热力学稳定性低于起始材料。提出了一种机制来合理化这种不平衡行为,该机制可以作为设计由激发态氧化还原事件驱动的其他逆热力学转换的模型。
Analogues ofα-Campholenal (= (1R)-2,2,3-Trimethylcyclopent-3-ene-1-acetaldehyde) as Building Blocks for (+)-β-Necrodol (= (1S,3S)-2,2,3-Trimethyl-4-methylenecyclopentanemethanol) and Sandalwood-like Alcohols
relationships (SARs) of sandalwood-like alcohols derived from analogues of α-campholenal (= (1R)-2,2,3-trimethylcyclopent-3-ene-1-acetaldehyde), we isomerized the epoxy-isopropyl-apopinene (−)-2d to the corresponding unreported α-campholenal analogue (+)-4d (Scheme 1). Derived from the known 3-demethyl-α-campholenal (+)-4a, we prepared the saturated analogue (+)-5a by hydrogenation, while the heterocyclic aldehyde