The general objective of this program is to develop new chemical reactions and synthesis strategies that will allow complex organic chemicals to be synthesized efficiently. As a result of the central importance of carbon in organic chemistry,our studies focus on the development of new selective (chemo-,regio-, and stereoselective) methods for forming carbon-carbon bonds. The studies proposed are broad in scope and encompass both mechanistic studies aimed at developing a fundamental understanding of chemical reactivity and total synthesis studies aimed at exploring the utility of the reactions we are developing for the preparation of specific complex target structures. The majority of our efforts during the proposed project period will focus on developing new cyclization reactions to prepare medium ring heterocycles and carbocycles. Of all the types of ring systems (small, common, medium and large) existing methods are least satisfactory for preparing medium rings. Our studies are based on an important discovery made during the current grant period that medium ring ethers can be formed efficiently by simple acetal-alkene cyclizations. Other investigations will focus on developing new methods to prepare monocyclic b-lactams in enantiomerically pure form. We will also continue our collaborative computational and experimental investigations to develop new models for predicting regio- and stereoselectivity in Diels-Adler reactions of highly functionalized cycloaddition components.
