Stoichiometric and Catalytic Transformations Using Transition Metal Aryloxides

该奖项由普渡大学化学系Ian P. Rothwell博士在无机、生物无机和有机金属化学项目中获得，多学科活动办公室对仪器的贡献支持了过渡金属羰基氧化物的研究。钛基氧化物是不饱和有机分子区域选择性偶联和立体选择性偶联的催化剂。环二烯和各种烯烃和炔烃都能发生这种反应。在这里，反应的合成用途将被开发，控制产品几何形状的机制将被确定。此外，还将对低价钨基氧化物作为4电子还原剂进行测试。新开发的配体2,6-二酚-3,5-二叔丁基苯酚将用于合成高价的早期过渡金属有机金属化合物和高亲电性、低配位的过渡金属化合物。与过去使用的类似配体相比，这种配体不经历金属化。这些配体中邻苯取代基的螯合作用为研究新型金属-芳烃键和反应性打开了大门，包括ch键激活和立体特异性偶联。与过渡金属结合在一起的空间体积大的基团通常能有效地阻止一定尺寸和形状的反应物进入金属中心。因此，确实发生的反应产生具有首选几何形状的产物。在本研究中，大块的醇氧基将用于影响一些钛和钨促进的立体特异性反应，这些反应在有机化合物的合成中很有用。

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.