| Résumé: | <p>This thesis is concerned with the development of ring-closing iodoamination and ringexpansion methodology and its subsequent application to the asymmetric syntheses of pyrrolidine and piperidine iminosugars.</p> <p><strong>Chapter 1</strong> highlights the remarkable biological properties displayed by iminosugars and introduces methods for the formation of the pyrrolidine and piperidine sub-classes.</p> <p><strong>Chapter 2</strong> describes investigations into the ring-closing iodoamination of bishomoallylic amines which occurs with concomitant <i>N</i>-debenzylation to give an iodomethyl pyrrolidine scaffold. Conversion to the corresponding aziridinium species followed by its regioselective intermolecular ring-opening by H<sub>2</sub>O enabled the synthesis of (+)-2,5-dideoxy-2,5-imino-Dglucitol (DGDP). A protocol for the preparation of its 1-deoxy-1-amino analogue (+)-ADGDP was also developed.</p> <p><strong>Chapter 3</strong> details studies into the ring-expansion of iodomethyl pyrrolidine scaffolds via the trapping of CO<sub>2</sub> (from NaHCO<sub>3</sub>) to produce cyclic carbonates as single diastereoisomers. Subsequent deprotection of these piperidines allowed the syntheses of (−)-1-deoxymannojirimycin (DMJ) and (+)-1-deoxyallonojirimycin (DANJ) to be completed.</p> <p><strong>Chapter 4</strong> delineates investigations into the trapping of alternative “X=C=Y” electrophiles, via the ring-expansion methodology developed in Chapter 3, initially utilising a model system. These studies culminated in the development of the trapping of <i>p</i>-TsNCO and the application of this methodology in the total asymmetric syntheses of (−)-ADMJ and (+)-ADANJ, the 2-deoxy-2-amino analogues of (−)-DMJ and (+)-DANJ, respectively.</p> <p><strong>Chapter 5</strong> contains full experimental procedures and characterisation data for all compounds synthesised in Chapters 2, 3 and 4.</p>
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