The pursuit of C(sp3)-enriched three-dimensional (3D) scaffolds as isosteric analogs for planar aromatic compounds is an area of increasing interest. In this report, we report a pyridine-boryl radical-catalyzed [3π + 2σ] cycloaddition reaction between vinyl azides and bicyclo[1.1.0]butanes (BCBs). The reaction leads to the synthesis of semisaturated bridged 2-azabicyclo[3.1.1]heptenes, a structural framework previously inaccessible. The semisaturation characteristic of these scaffolds results in an effective reproduction of the geometry of 1,3,5-substituted pyridine, with the imine group exhibiting comparable basicity to pyridine rings. Synthetic manipulation of these products reveals valuable synthetic handles, enabling a modular approach to the synthesis of potential pyridine isosteres.

中文翻译：

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吡啶-硼基自由基催化的 [3π + 2σ] 环加成反应，用于合成吡啶等排体


追求富含 C（sp3） 的三维 （3D） 支架作为平面芳香族化合物的等位类似物是一个越来越受关注的领域。在本报告中，我们报道了乙烯基叠氮化物和双环 [1.1.0] 丁烷 （BCB） 之间吡啶-硼自由基催化的 [3π + 2σ] 环加成反应。该反应导致半饱和桥式 2-氮杂双环[3.1.1]庚烯的合成，这是一种以前无法获得的结构框架。这些支架的半饱和特性导致 1,3,5-取代吡啶的几何形状的有效再现，其中亚胺基团表现出与吡啶环相当的碱度。这些产品的合成操作揭示了有价值的合成手柄，从而能够采用模块化方法合成潜在的吡啶等体。