Development of recyclable fluorous oxidation catalysts: Sigmatropic rearrangements for peptide chemistry

The work described in this thesis involves the development of recyclable fluorous organoselenium catalysts for oxidations incarnating the principles of the green chemistry concept. The design, synthesis and applications of a perfluorous seleninic acid catalyst in allylic oxidation are presented. In conjunction with iodoxybenzene, the perfluorous catalyst is found to bring about the allylic oxidation of alkenes to enones. Following a reduction protocol in the workup, the fluorous catalyst can be recovered for reuse by a simple continuous fluorous extraction. Further investigations of the perfluorous seleninic acid in oxidations adjacent to carbonyl groups and at benzylic positions as a recyclable catalyst are also described.;The investigation of sigmatropic rearrangements as tools for site-selective modification of amino acid and peptide targets is described. Through allylic sulfur ylide rearrangements, a variety of functionalities, such as lipid-like residues, fluorous ponytails, and mono and disaccharides, are successfully attached onto small peptides. The exploration of transition metal catalyzed cyclopropanation as a novel approach for the synthesis of a new class of pseudo-oligosaccharides is also presented.