Studies On The Asymmetric Total Syntheses Of The Natural Product Tuxpanolide And Several Insect Pheromones

This thesis mainly aims at the studies on the asymmetric total syntheses of Tuxpanolide (1) and several natural insect pheromones. The L-proline-catalyzed asymmetric aldol condensation of cyclobutanone with various aldehydes was also investigated.The thesis consists of the following three parts:Part I Studies on the asymmetric total syntheses of the natural product Tuxpanolide(1)1. The first asymmetric total synthesis of Tuxpanolide (1), a novel naturallyoccurringα-alkylidene-β-hydroxy-γ-butyrolactones, has been achieved from readily isobutylaldehyde in eighteen steps, which involved Wittig reaction, Sharpless's asymmetric epoxidation, Swern oxidation, Sharpless's asymmetric dihydroxylation. The key step is the aldol reaction. The absolute stereochemistry was established by employing Sharpless's asymmetric dihydroxylation, but the absolute stereochemistry of C-8 was not be confirmed yet.2. A new designed the synthetic route of Tuxpanolide (1). The first syntheses of the precursor 60 of Tuxpanolide was accomplished in several steps from commercially available nerol as starting material, which involved Brown's asymmetric allylic alkylation reaction, Sharpless's asymmetric dihydroxylation, and Aldol reaction.Part II Asymmetric syntheses of several natural insect pheromones1. The natural insect pheromone, (-)-(5R,6S)-6-acetoxyhexadecan-5-olide and(-)-(5S)-hexadecanolide, were synthesized from readily available undecanal and cyclopentanone. Furthermore, the asymmetric syntheses of (+)-(7R, 8S)-disparlure were achieved, using L-proline catalyzed asymmetric aldol reactions and Baeyer-Villiger oxidation as the key steps.2. The L-proline-catalyzed asymmetric direct aldol reactions of cyclobutanone with various aldehydes were investigated in detail. The synthetic studies on thenatural muricatacin were also attempted..Part III Review of the L-Proline-catalyzed asymmetric reaction The L-Proline-catalyzed asymmetric reaction was summarized. The L-proline-catalyzed asymmetric aldol reaction and it's mechanism were described in detail. Meanwhile, we summarized the other asymmetric reactions catalyzed by L-proline either. 41 references were quoted in this part.