The focus of this research is to expand the basic set of chemical reactions available to the organic chemist for application to the synthesis of complex molecules. There are five areas of concentration. The first is the development of addition reactions based upon the excellent coordination chemistry of acetylenes with transition metals. In this context, new classes of cycloaddition reactions will emerge which build molecular complexity rapidly. The second area involves allylpalladium chemistry whereby a series of modularly designed ligands controls absolute stereochemistry or chirality. The third area involves the ability of silicon to promote carbon-carbon bond formation. The fourth area probes the development of phosphines as novel catalysts. Finally, the fifth area builds upon the versatility of sulfur to impart unusual reactivity, especially in sulfones and sulfenium ions. With this award, the Synthetic Organic Program is supporting the research of Dr. Barry M. Trost of the Department of Chemistry at Stanford University. Professor Trost will focus his work on developing efficient synthetic methodology which is applicable to approaches to complex organic molecules of theoretical and biological interest. The use of organometallic intermediates, both catlytic and stoichiometric, is stressed in the work.