The Organic Synthesis Program is supporting the work of Dr. William Wulff. Wulff, a professor of chemistry at the University of Chicago, is investigating how metals can be used to develop novel reagents that provide unique methods for constructing complex organic molecules. Wulff's work is characterized by the basic new knowledge that results as well as interesting applications to natural products syntheses. A goal of the work is the development of metal-carbene complexes that allow for immediate assembly of ring systems. The chemistry of chromium, molybdenum, tungsten and manganese carbene complexes, and their use in organic synthesis is the basis for this proposal. New annulation protocols are being developed which will find application in the construction of polycyclic systems characteristic of a number of classes of natural products. Included in these studies are ?2 + 2! and ?3 + 2! cycloaddition reactions. Basic investigations of the influences of structure, solvent, and metals to the success of the reactions will be an integral part of this work. Detailed mechanism analyses will provide the basis for predicting how structural and electronic features of the metal-carbene complex and the substrate will influence the scope of the reaction.