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.
