Department of Chemistry
The primary goal of our research program is the development of new methods and strategies for the synthesis of biologically active and structurally interesting natural products. A summary of the synthetic methods we have developed and the syntheses we have achieved since 1981, along with our current research efforts, are presented within the links, "Completed Projects" and "Ongoing Research," respectively.
A common theme thoroughout our research is the development of new procedures to make polycyclic ring systems. For example, from 1982 to 1992 we developed annulation methods for the formation of five-, six-, seven- and eight-membered rings based on the intramolecular addition of allylsilanes to various Michael acceptors. These ring-forming strategies were featured in the synthesis of various terpenes, some rather simple and others significantly more complex. In the process of carrying out this research, we developed novel procedures for the preparation of allylsilanes and functionalized conjugated dienones. During the past decade we have focussed on using cyclialkylations, or intramolecular Friedel-Crafts reactions, to create polycyclic ring systems having 5,7,6-, 6,7,6- or 6,6,6-fused tricyclic skeletons. These new annulation methods have permitted the synthesis of several challenging natural products and have resulted in the development of new procedures for the preparation of aryl bromides, the epoxidation of olefins, and mild dehydration of alcohols.
Another aspect of our research program focuses on the isolation of natural products from plants found in northeastern Brazil, a collaborative project with Dr. Jnanabrata Bhattacharyya and Dr. Reinaldo Almeida of the Laboratorio de Technolgia of the University Federal de Paraiba (Brazil). To date, several new natural products have been isolated and characterized. These studies are becoming a more significant part of our overall research program since several of the compounds that we've isolated have shown promise for the treatment of kidney stones and prostate gland disorders, and some possess morphine-like activity. More importantly, the synthesis of these compounds, most of which are flavonoids, is being activity pursued and our Brazilian co-workers continue to send us additional extracts with promising bioactivity based on rain-forest folklore.
For the past five years, a fruitful collaboration has evolved with the scientists at Environmental Protection Agency labs in Athens in a project to systematically identify the byproducts of disinfection unfortunately present in our drinking water. While the structures of most of the compounds are rather simple, their preparation can often be extremely challenging and most of these highly halogenated or oxidized byproducts have turned out to be extremely toxic.
During the summer of 1986, Raymond Giguere and I began using microwave irradation to facilitate Diels-Alder reactions, ortho-Claisen rearrangements and other pericyclic reactions. The report by Richard Gedeye and co-workers of their independent work in August of 1986 led us to publish our preliminary findings. Indeed, our 1986 paper and the Gedeye manuscript are generally recognized as having created the field of microwave-promoted organic chemistry. To date, over 700 papers have been published worldwide in this area. Without doubt, the greatest impact of this work has been for the rapid preparation of radio-labelled drugs by hospitals for the treatment or testing of patients. The availability of microwave instruments capable of controlling both the temperature and pressure of reactions has been a productive area of study for us and remains so. Recent efforts have been directed at incorporating microwave-based mutli-step total synthesis into undergraduate instructional programs.
In 1999 I served as the Chair for the Gordon Research Conference on Natural Products and Chair of the Northeast Georgia Section of the American Chemical Society. This service to the scientific community has been included within this website.