| 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. |
