Stoichiometric and Catalytic Transformations Using Transition Metal Aryloxides

这一无机化学、生物无机化学和金属有机化学项目的奖项以及多学科活动办公室对仪器的贡献，支持了普渡大学化学系Ian P.Rothwell博士对过渡金属芳氧化物的研究。芳氧钛是不饱和有机分子区域选择性和立体选择性偶联的催化剂。环二烯和各种烯烃和炔烃已被证明发生了这种类型的反应。在这里，将开发反应的合成用途，并确定控制产品几何形状的机理。此外，低价芳氧钨将作为4电子还原剂进行测试。新开发的配体2，6-二苯酚-3，5-二叔丁基苯酚将用于合成高价早过渡金属有机金属化合物和高亲电、低配位的过渡金属化合物。与过去使用的类似配体不同，这种配体不会发生金属化。通过邻苯基在这些配体中的络合作用为研究新型的金属-芳烃成键和反应活性打开了大门，包括CH键活化和立体专一性偶联。与过渡金属结合的空间大体积基团通常能有效地阻止某些大小和形状的反应物进入金属中心。因此，确实发生的反应会产生具有首选几何构型的产品。在这项研究中，大量的醇氧基将被用来影响一些钛和钨促进的反应的立体特异性反应，这些反应在有机化合物的合成中是有用的。

This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program with a contribution for instrumentation from the Office of Multidisciplinary Activities supports research on transition metal aryloxides by Dr. Ian P. Rothwell, Department of Chemistry, Purdue University. Titanium aryloxides are catalysts for regio- and stereoselective coupling of unsaturated organic molecules. Cyclodienes and various olefins and alkynes have been shown to undergo this type of reaction. Here the synthetic usefulness of the reaction will be exploited and the mechanism that controls product geometry will be determined. In addition, low valent tungsten aryloxides will be tested as 4-electron reducing agents. A newly developed ligand, 2,6-diphenol-3,5-di-tert-butylphenol, will be used to synthesize high valent early transition metal organometallic compounds and highly electrophilic, low coordination transition metal compounds. In contrast to analogous ligands used in the past, this ligand does not undergo metalation. Chelation via ortho-phenyl substitutents within these ligands opens the door for investigation of new types of metal-arene bonding and reactivity, including CH-bond activation and stereospecific coupling. Sterically bulky groups bound to transition metals are often effective in preventing reactants of certain size and shape from accessing the metal center. As a consequence, the reactions that do occur produce products with a preferred geometry. In this study, bulky alkoxide groups will be used to effect stereospecific reactivity to some titanium- and tungsten-promoted reactions of utility in the synthesis of organic compounds.