有机锑配合物路易斯酸碱催化剂催化C-H键官能团化反应研究

Organoantimony complexes with 5,6,7,12-tetrahydrodibenzo[c,f][1,5]azastibocine framework are synthesized as template to catalyze the functionalization of alkyne, alkene or alkane C-H bond with imine or other unsaturated substrates under mild conditions. The goal is to have value-added use of our rich antimony resource. The common problems of C-H functionalization are low selectivity, poor recyclability and complexity of catalytic systems. The advantages of employing organometallic catalysts are that they are controllable and adjustable for achieving high activity, selectivity and stability. To reveal the reaction mechanism of C-H functionalization, we shall perform theoretical calculations, isotope labeling as well as sub-step control of the reaction for the capture of intermediates. The separated intermediates will be subject to X-ray single crystal diffraction and NMR analysis. Furthermore, research will be conducted to achieve precise control of chemo-, regio-, and stereoselectivity through the modulation of the catalytic system and reaction conditions, and thus reverse guiding the synthesis of the organoantimony complexes. To regulate structure and catalytic properties, we will introduce functional groups to the aromatic ring of the complex via ortho-C(sp2)-H functionalization so as to modulate the electronic and steric effects. In the reaction system, the N-Sb coordinating bond of the catalyst will be dissociated during oxidative addition, and coordinated during reductive elimination, thus stabilizing the catalyst structure and accelerating the reaction. The proposed investigation has scientific and practical significance: A series of efficient and affordable organoantimony catalysts with Lewis acidic/basic and redox activities will be generated by green methods, and completely independent intellectual property acquired for the synthesis of organic functional molecules.

本项目针对我国丰富锑资源的高值化利用需求以及C-H键官能团化反应存在的催化体系复杂、选择性差且难回收等难题，结合金属配合物催化活性、选择性与稳定性可控可调的优点；提出以具酸碱协同和氧化还原催化性能的氮锑辛烯骨架配合物为模板催化剂探讨其与亚胺等底物在温和条件下协同催化C-H键的官能团化反应，并通过理论计算、分步控制反应、同位素标记捕捉中间体、分离后的中间体采用单晶、核磁表征，揭示反应机理。通过调变配合物催化体系和反应条件实现对反应的精密控制，并以此逆向指导配合物的合成。以氮锑辛烯骨架配合物为底物，通过C-H活化在其芳环邻位导入功能基团实现对配合物结构和催化性能的调控。该类配合物的配位键在氧化加成时解离、还原消除时配位，稳定配合物结构并加速反应进行。本项目的实施，有望得到具有工业化应用前景的我国完全自主知识产权的有机锑配合物高效廉价催化剂及其绿色催化合成方法，具有重要的科学价值和应用价值。

有机锑化学发展一直很缓慢，最主要的原因是构建有机锑的方法比较困难，最大的难点在于形成稳定C-Sb键，但是可用的配体极其有限。因此，如何通过简单的稳定有机锑氯化物合成多种新型有机锑化合物是一个可行的路径。项目组系统发展了有机锑配合物的催化合成方法，筛选出了一类高效廉价绿色的有机锑配合物，发现了有机锑试剂具有双亲性，并可作为偶联试剂的催化剂体系高选择性控制合成联苯类化合物、烯烃、 炔烃和饱和碳功能分子，建立了有机锑配合物作为偶联试剂催化合成有机功能分子的廉价、高效的催化合成法。基于有机锑配合物发展了其作为催化剂绿色催化合成体系，考察了各配合物在胺、醛、酮的区域选择性Mannich反应，醛、酮的区域选择性缩合反应，醛、胺、炔芳构化反应以及环氧化合物胺解反应中的催化性能。通过计算各配合物的氟离子亲和力强度，建立了N→Sb配位键与配合物的路易斯酸强度及其催化性能的相关性。发现了有机锑配合物可以作为配体催化炔烃的高区域选择性半加氢，还可催化Buchwald-Hartwig反应合成咔唑类化合物，发现锑作为配体中心原子有利于与金属中心形成反馈π键，具有类似于极易氧化的三叔丁基膦的效果。.另外还建立了C-H键官能团化反应构建功能有机配体的一般性研究方法，在8-氨基喹啉类化合物、苯并呋喃酮类、吲哚啉类化合物的催化转化方面确立一般性的有机功能配体的合成新方法，开发其应用（材料、医药、生命领域等）。深入研究了部分通过绿色催化合成法合成的有机功能新分子的生物活性，部分表现出非常优越的抗肿瘤活性、抗菌活性和抗炎活性。.其他还开展了茂金属催化酯化反应，含硫化合物的无金属催化合成和噁唑啉类P/N配体的催化合成及应用。