受阻路易斯酸碱对调节芳香环碳氢官能化反应机理研究

Carbon-Hydrogen (C-H) bond activation/functionalization reaction converts inert C-H bonds into carbon-carbon and carbon-heteroatom bonds directly and efficiently. The method has been widely used in the synthesis of complex chemicals such as drugs, natural products and polymer materials. The recently developed Frustrated Lewis pair (FLP)-mediated C-H bond functionalization provides a low-toxic and economic metal-free method for aromatic compound modification. Expanding the substrate range to electron-deficient aromatic rings and controlling the regio-selectivity are the major challenges in this area. The doubts about the reaction mechanism and selectivity control factors could limit the process of overcoming the challenges. In this project, through the theoretical calculation method based on quantum chemical platform, we shall to systematically investigate the FLP-mediated C(sp2)-H bond functionalization of aromatic substrates. Effort will be emphasized on illustrating the reaction mechanism of the borane/amine FLP system-mediated C(sp2)-H borylation of heteroarenes and substituted benzene, and C(sp2)-H alkylation of phenol in borane-catalyzed system. Revealing the favorable mechanism, rate-determining step and structural information of the key intermediate and transition state. Based on these, we further investigate regio-selectivity phenomena in the reaction, clarifying the selectivity control factors. It is hoped to offer new ideas for helping design highly reactive and specifically selective C-H bond functionalization reactions.

碳氢键活化官能化反应将惰性碳氢键直接高效的转化为碳碳和碳杂原子键，在药物、天然产物和高分子材料等复杂结构化学品的合成领域具有广泛应用。受阻路易斯酸碱对（FLP: Frustrated Lewis pair）体系调节芳香环碳氢活化官能化反应为芳香族底物修饰提供了经济低毒的非金属催化方法。拓展底物范围到缺电子芳环和控制反应区域选择性是这类反应面临的重要挑战。然而对反应机理和选择性影响因素的疑惑不利于完成上述挑战。本项目拟运用理论计算方法研究FLP体系调节的芳香环底物碳氢官能化反应。阐明硼烷/胺FLP体系调节五元杂芳环碳氢硼化和取代苯碳氢硼化，以及硼烷/苯酚体系中苯酚碳氢烷基化反应机理。揭示反应的优势机理，归纳速率决定步骤和关键中间体过渡态的结构能量信息。基于此研究反应中的区域选择性现象，揭示选择性的影响因素及具体作用方式。为设计更多高反应活性和专一选择性的芳香环碳氢官能化反应提供理论依据。

受阻路易斯酸碱对（FLP）体系调节的芳香环碳氢活化官能化反应，作为芳香族底物修饰方法中经济低毒的非金属催化方法而备受关注。本项目考察 FLP 体系调节的芳香环底物碳氢键活化官能化反应，针对反应机理和区域选择性影响因素不明确等问题展开研究。针对路易斯酸B(C6F5)3与重氮酯组成的FLP体系催化苯酚碳氢烷基化反应，系统阐述反应机理并揭示C-H活化而非O-H活化的化学选择性，以及邻位C-H活化而非对位C-H活化的区域选择性原因。基于此探究烷基偕二硼、频哪醇硼酯等路易斯酸性硼试剂参与烷基硼化/硼酯化反应区域选择性影响因素，揭示了溶剂控制的烯丙基磷酸酯与烷基偕二硼选择性烷基硼化反应区域选择性，及配体控制炔烃的选择性烷基硼化反应区域选择性原因。进一步将FLP体系的催化范围拓展到锂硫电池领域，揭示硼掺杂黑磷中B/P路易斯酸碱对催化多硫化物转化的机理，预测路易斯酸性B黑磷是优于黑磷的电极催化材料。本项目不仅解决了FLP催化碳氢键活化机理和选择性等基础共性问题，并且积极拓展FLP体系在电催化领域的应用前景，兼具理论指导和实际应用价值。