The aza Paternò–Büchi reaction is a [2+2]-cycloaddition reaction between imines and alkenes that produces azetidines, four-membered nitrogen-containing heterocycles. Currently, successful examples rely primarily on either intramolecular variants or cyclic imine equivalents. To unlock the full synthetic potential of aza Paternò–Büchi reactions, it is essential to extend the reaction to acyclic imine equivalents. Here, we report that matching of the frontier molecular orbital energies of alkenes with those of acyclic oximes enables visible light–mediated aza Paternò–Büchi reactions through triplet energy transfer catalysis. The utility of this reaction is further showcased in the synthesis of epi- penaresidin B. Density functional theory computations reveal that a competition between the desired [2+2]-cycloaddition and alkene dimerization determines the success of the reaction. Frontier orbital energy matching between the reactive components lowers transition-state energy (Δ G ǂ ) values and ultimately promotes reactivity.

中文翻译：

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可见光介导的无环肟和烯烃生成氮杂环丁烷的氮杂 Paternò-Büchi 反应


aza Paternò-Büchi 反应是亚胺和烯烃之间的 [2+2]-环加成反应，产生氮杂环丁烷（四元含氮杂环）。目前，成功的例子主要依赖于分子内变体或环状亚胺等价物。为了充分发挥氮杂Paternò-Büchi反应的合成潜力，必须将该反应扩展到无环亚胺等价物。在这里，我们报道了烯烃的前沿分子轨道能量与无环肟的前沿分子轨道能量的匹配，通过三重态能量转移催化实现可见光介导的氮杂Paternò-Büchi反应。该反应的实用性在表佩那西丁 B 的合成中得到了进一步展示。密度泛函理论计算表明，所需的 [2+2]-环加成和烯烃二聚之间的竞争决定了反应的成功。反应组分之间的前沿轨道能量匹配降低了过渡态能量 (Δ G ) 值并最终促进反应性。