In this award in the Inorganic, Bioinorganic and Organometallic Chemistry Program, Ian P. Rothwell of Purdue University will continue studies in the chemistry of transition and main group elements bound with aryloxide ligands. The results of the project are expected to provide a deeper understanding of the chemical reactivities of organic molecules which are attached to metal atoms and may lead to improved syntheses of some organic compounds. The research effort will include four aspects. The first involves the investigation of the synthetic utility and mechanistic details of intramolecular carbon-hydrogen bond activation by both d-block and p-block metals. Another area involves the exploitation of the potent reducing power of low valent early d-block metal aryloxide compounds. The third area involves the synthetic and mechanistic study of p-block metal hydrides to stepwise hydrogenate intramolecular aryloxide ligands. The final thrust is to investigate the hydrogenation of aryl-phosphine and arsine ligands. Also included in the last study will be efforts to carry out catalytic asymmetric hydro- genations of prochiral phosphine and arsine ligands.