In this project which is supported by the Inorganic, Bioinorganic and Organometallic Chemistry Program, Dr. Joseph O'Connor of the University of California, San Diego will pursue an investigation of the synthesis, structural elucidation, and mechanistic aspects of formation and reaction of metallacyclobutene complexes. Dr. O'Connor has already discovered one method that should produce a range of metallacyclobutenes of late transition metals where there is a paucity of examples and even fewer studies of reactivity. Reactions to be studied include conversion of the metallacyclobutenes to cyclopentadienes and other five-membered rings, which are useful intermediates for organic synthesis, by reactions with alkynes and olefins. A novel photochromic effect that was observed in the substitution reaction of phosphorus donors in one cobaltacyclobutene complex will be examined by time-resolved spectroscopic methods. This project involves fundamental investigations of the synthesis and reactivity of a new class of organometallic compound known as metallacyclobutenes. The examples of interest for these studies contain late transition elements. The major objective is the development of new synthetic methods that may be used in total synthesis of natural products and their homologs. Some of these may ultimately find application as new pharmaceuticals.
