New Methods in Stereoselective Synthesis

Boston College, Chestnut Hill MA

Investigators

Abstract

This project addresses the development of new ruthenium-based chiral catalysts for enantioselective olefin metathesis. A new approach for stereoselective olefin metathesis, involving two-point association of substrates with the catalyst, will be developed, significantly expanding the scope of olefin metathesis. Issues of practicality and selectivity are particularly emphasized, and all the reactions under study can be run in air with undistilled solvents. The mechanisms of activity that are unique to the catalysts and transformations developed in this program will be elucidated. Such mechanistic information will then constitute the basis for design of new metathesis catalysts that are highly reliable and practical and exhibit unprecedented activity. The new catalysts will be used to develop new asymmetric ring-closing, ring-opening and cross-metathesis reactions. The utility of new catalysts will be demonstrated by the preparation of complex natural products. The project also aims to establish the parameters that govern directed catalytic olefin metathesis reactions as well as determine the full range of directing units that can be effectively utilized. These investigations will lead to the development of the first readily available, easily removable and effective class of chiral auxiliaries for highly stereoselective olefin metathesis. The "olefin metathesis" reaction, which can efficiently afford a wide range of organic molecules that are difficult to access by other methods, has proven to be a singularly powerful and unique catalytic transformation that has already had a tremendous impact not only in organic chemistry but also in medicinal, biological and material chemistry. At the heart of the success of olefin metathesis is the efficiency of catalysts that promote these important processes. With the support of the Organic and Macromolecular Chemistry Program, Professor Amir Hoveyda, of the Department of Chemistry at Boston College, is exploring the design and function of new catalysts for the olefin metathesis reaction. Study and development of new chemical reactions is a fundamental and significant objective of modern chemistry. New reactions allow access to many important molecules that were previously out of reach. Of particular importance are the design and development of reactions that are initiated by a catalyst and deliver products that predominantly consist of a single stereoisomer (stereoselective). Within this context, the introduction of catalytic stereoselective olefin metathesis reactions will have a tremendous impact on many branches of organic chemistry.