With the support of the Organic and Macromolecular Chemistry Program, Professor Eric J. Enholm, of the Department of Chemistry at the University of Florida, is developing new methods for free radical reactions on reusable solid supports. Professor Enholm uses ring-opening metathesis methodology to prepare new soluble polymers to serve as supports for free radical transformations. Following establishment of the methodology through the analysis of established radical reactions, including tin hydride reduction of halides, radical cyclizations, and one-electron allyl transfers, new chiral reactions will be examined. The latter will include polymer-supported versions of the asymmetric "interrupted" Kharasch atom transfer and catalytic asymmetric Giese reactions. Reusable chiral scaffolds, with enantiopure stereo-directing elements imbedded in the support, will be prepared, and catalytic asymmetric transformations, particularly those allowing for enantioselective acyclic stereocontrol in radical and ketyl radical-anion transformations, will be explored.
Molecular species bearing unpaired electrons ("free radicals") have historically been viewed as highly reactive and therefore relatively chemically undiscriminating intermediates. Recent studies have demonstrated that the reactivity of these radicals may be harnessed, allowing the selective and effective synthesis of a variety of significant organic molecular structures. With the support of the Organic and Macromolecular Chemistry Program, Professor Eric J. Enholm, of the Department of Chemistry at the University of Florida, is exploring new methods for carrying out reactions of organic radicals. By exploring radical reactions tethered to polymeric supports, the properties of the polymer may be used both to control the outcome of the radical reactions and to facilitate separation of desired materials from waste products. These studies are leading to new and general methodologies for the synthesis of complex organic molecules and to the development of polymer-supported reaction chemistry of relevance to the fields of combinatorial chemistry and solid-phase organic chemistry.
