内离子对型烯烃复分解催化剂的合成与催化研究

Research on the synthesis of new olefin metathesis catalysts and its application has been one of the focuses in the field of organic chemistry. The currently available ruthenium carbene catalysts are not stable, especially in solution. Degradation of the ruthenium carbene catalysts during the catalytic reaction is very fast, which is significantly lowing down the efficiency of these catalysts (typically the TON <1000), and the resulted product contains many ruthenium residuals, which require further purification. In this proposal, a new kind of olefin metathesis catalyst bearing a cationic metal carbene center and an intramolecular anionic pair will be prepared. We hope that the weakly coordination of the intramolecular anionic pair to the cationic metal center could significantly speed up the complexation rate of olefins, and thereby increase the catalytic activity (TOF) of the metal center. The coordination of the limited and bulky anion to the cationic metal center should be able to prevent the deactivation of the metal center by dimerization or polymerization of these active sets, thereby improving the catalytic efficiency (TON); The intramolecular coordination of the bulky anion to the cationic metal center should make up the instability of the metal center due to the coordinative unsaturated of the ligands, and then solve the shortcomings of easy degradation of the ruthenium olefin metathesis catalysts with the carbene ligand in the liquid phase. Not only is the study able to provide highly active olefin metathesis catalyst with independent property rights, but also enrich the types of new efficient olefin metathesis catalysts. The success of this proposal will provide a theoretical basis for the design of new and efficient olefin metathesis catalysts.

烯烃复分解催化剂的合成与应用研究是有机化学的研究热点之一。传统的钌催化剂稳定性不好，催化剂在催化反应过程中以较快的速度降解，使得此类催化剂的催化效率较低(通常TON<1000),且产物中具有较多的钌残余。本课题将合成一类高活性的、具有内离子对构型的阳离子金属卡宾烯烃复分解催化剂,期望通过配位不饱和的中心阳离子特性加快络合烯烃的速率，进而提高催化活性(TOF)；通过受限的、大空阻的阴离子阻止活性阳离子中心通过二聚或多聚失活，进而提高催化效率(TON)；通过阴离子大空阻作用弥补阳离子中心由于配位不饱和带来的不稳定性，进而解决卡宾配位的钌烯烃复分解催化剂在液相反应时易降解的缺点。此项研究不但能够提供一种具有自主产权的高活性烯烃复分解催化剂，丰富烯烃复分解催化剂的种类，也为新型高效烯烃复分解催化剂的设计、合成提供理论研究依据。

本课题针对传统的钌烯烃复分解催化剂稳定性不好，催化效率较低等问题，试图设计、合成一类具有内离子对构型的阳离子金属卡宾烯烃复分解催化剂，期望通过配位不饱和的中心阳离子特性加快络合烯烃的速率，进而提高催化活性。我们合成了一类含有螯合基团、大空阻、弱配位的硼酸阴离子，对构建内离子对型的钌金属卡宾配合物进行了一系列探索性研究。我们成功地合成了一系列含氮螯合配体的高效钌烯烃复分解催化剂，其合成简单，结构新颖，具有良好的热稳定性。该类催化剂用于烯烃复分解反应时，引发快，转化率高，不需要外加Brønsted，或Lewis 酸活化。这类新催化剂与Grubbs II型，Hoveyda II型催化剂具有相当的催化活性，拥有类似的官能团适应性。此项研究不但解决了含氮螯合配体的烯烃复分解催化剂配体难以解离，催化活性、效率低的问题，也为高效烯烃复分解添加了一类新结构催化剂。通过引入具有pH值响应的吲哚[2,1-b]恶唑烷取代基，合成了一种通过pH调控可回收的高效钌卡宾烯烃复分解反应催化剂，为解决均相催化剂的回收、再利用难题提供了一种可能性。合成了一系列含1,2-二巯基-1,2-碳硼烷配体、邻位取代的2-巯基苯酚、 1,8-二巯基萘、3,4二巯基环丁-3-烯-1,2-二酮配体的高Z-选择性钌卡宾烯烃复分解催化剂。此外，我们还发展了一种铑催化的茚三酮和炔烃脱羰环加成反应，提供了一种非张力环酮C-C键活化新模型，在碳-碳键活化方面具有较大的理论研究意义；建立了一种钯催化碳-氢键的活化与偶联反应，可简洁、高效的合成芴酮类化合物，具有良好的应用前景；发现了一种铑催化的芳基伯醇与芳基硼酸氧化偶联反应，实现了伯醇C−C键断裂反应，丰富了碳-碳键活化反应内容。发展了一种铑催化扁桃酸和炔烃脱酸环加成反应为构建茚酮衍生物提供了一种有潜在应用价值的合成新方法。