Beduru Srinivas, Huple Deepak B, Kutateladze Andrei G
Department of Chemistry and Biochemistry, University of Denver, Denver, CO, 80208.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202415176. doi: 10.1002/anie.202415176. Epub 2024 Nov 6.
Dearomative cycloadditions offer rapid access to complex 3D molecular architectures, commonly via a sp-to-sp rehybridization of two atoms of an aromatic ring. Here we report that the 6e π-system of a benzenoid aromatic pendant could be exhaustively depleted within a single photochemical cascade. An implementation of this approach involves the initial dearomative [4+2] cycloaddition of the Excited State Intramolecular Proton Transfer (ESIPT)-generated azaxylylene, followed by two consecutive [2+2] cycloadditions of auxiliary π moieties strategically positioned in the photoprecursor. Such photochemical cascade fully dearomatizes the benzenoid aromatic ring, saturating all six sp atoms to yield a complex sp-rich scaffold with high control of its 3D molecular shape, rendering it a robust platform for rapid systematic mapping of underexplored chemical space. Significant growth of molecular complexity-starting with a modular synthesis of photoprecursors from readily available building blocks-is quantified by Böttcher score calculations.
脱芳构化环加成反应通常通过芳环上两个原子的sp到sp重新杂化，能够快速构建复杂的三维分子结构。在此，我们报道苯型芳香侧链的6eπ体系可以在单一光化学级联反应中被彻底消耗。这种方法的一个实例包括激发态分子内质子转移（ESIPT）产生的氮杂亚二甲苯首先进行脱芳构化[4+2]环加成反应，随后光前驱体中策略性定位的辅助π部分连续进行两次[2+2]环加成反应。这种光化学级联反应使苯型芳香环完全脱芳构化，使所有六个sp原子饱和，从而产生一个对其三维分子形状具有高度控制的富含sp的复杂支架，使其成为快速系统绘制未充分探索的化学空间的强大平台。从由易于获得的构建块进行光前驱体的模块化合成开始，分子复杂性的显著增长通过博特歇尔分数计算进行量化。
