The focus of this research is the synthesis of enantiomerically pure molecules using free radical reactions as the key synthetic step. This is based on the observation that small, seemingly reactive ring systems can be converted into radicals and be induced to undergo cyclization faster than rearrangement. This forms a new strategy for the construction of carbon-carbon bonds, and ultimately, more complex materials. Kinetics of these rapid radical rearrangements will also be studied. Oxiranylcarbinyl and aziridinyl radicals will be the focus of these studies. With this renewal award, the Synthetic Organic Program is supporting the research of Dr. Fred E. Ziegler of the Department of Chemistry at Yale University. Professor Ziegler will focus his research on carbon-carbon- bond formation, a fundamental process in the synthesis of organic molecules, using free radical reactions to provide enantiomerically pure materials. These studies will provide new avenues of synthesis that may be applicable to the preparation of important antibiotics through pathways inaccessible by anionic and cationic methods