Silver-Catalyzed Intermolecular [3 + 2]/[5 + 2] Annulation of N‑Arylpropiolamides with Vinyl Acids: Facile Synthesis of Fused 2H‑Benzo[b]azepin-2-ones

A silver-catalyzed oxidative intermolecular [3 + 2]/[5 + 2] annulation of N-arylpropiolamides with 4-vinyl acids for producing fused 2H-benzo­[b]­azepin-2-ones is described. This radical-mediated annulation reaction features broad substrate scope and excellent selectivity, and enables the formation of three new C–C bonds through oxidative decarboxylation, [3 + 2]/[5 + 2] annulations, and C­(sp2)-H functionalization cascades. Employing this silver-catalyzed oxidative strategy, common terminal alkynes were successfully converted into cyclopentenes via intermolecular [3 + 2] annulation.

本研究报道了一种银催化的氧化型分子间[N-芳基丙炔酰胺（N-arylpropiolamides）与4-乙烯基羧酸（4-vinyl acids）的[3+2]/[5+2]环化反应，可用于制备稠合2H-苯并[b]氮杂卓-2-酮。该自由基介导的环化反应具有底物适用范围广、选择性优异的特点，可通过氧化脱羧、[3+2]/[5+2]环化以及C(sp2)-氢官能化（C(sp2)-H functionalization）串联过程，构建三个全新的碳-碳键。借助该银催化氧化策略，普通末端炔烃（terminal alkynes）可通过分子间[3+2]环化反应成功转化为环戊烯（cyclopentenes）。