The chemoselective transformation of common but unreactive C-H bonds to other functional groups has the potential to revolutionize chemical synthesis. The primary goal of the proposed research is to develop rhodium porphyrin catalysts to activate and functionalize sp3 hybridized C-H bonds. Rhodium (II) porphyrin complexes can stoichiometrically activate sp3 C-H bonds over sp2 C-H bonds without the need for directing groups within the substrate while tolerating the types of functional groups present in bioactive compounds. This research will attempt to make this reaction more widely applicable by making the stoichiometric process into catalytic one by using nitroxide radicals to turn the products of this C-H activation, rhodium (III) alkyl and hydride species, into rhodium (II) porphyrins and useful organic products, namely alkenes. Nitroxide radicals were chosen for this study based on the known ability of these compounds to covert some rhodium (III) porphyrin hydrides to rhodium (II) porphyrins and the nitroxide promoted conversion of rhodium (III) pophyrin alkyls into alkenes. The new nitroxide radicals proposed herein will allow catalysis by avoiding known side reactions of the rhodium (II) porphyrins with previously used nitroxide radicals. ? ? ?
| Hongay, Cintia F; Grisafi, Paula L; Galitski, Timothy et al. (2006) Antisense transcription controls cell fate in Saccharomyces cerevisiae. Cell 127:735-45 |
