Piperidine Alkaloid (+)-febrifugine (-)-deoxoprosophylline And The Big Bag Moth Pheromone Of Asymmetric Synthesis

Natural products - a term used commonly in reference to chemical substances found in nature are end products of secondary metabolism of plants, animals or microorganism. Most natural products possess a variety of important bioactivities and about half of the clinic drugs come from natural products or their derivatives. Natural products are almost chiral compounds and their concentration in nature is low. So preparation of natural products through asymmetric synthetic method is important both academically and in practice.This dissertation is constituted by the following three parts:1 The asymmetric alkylation of N,O-acetal with silyl enol ethers catalyzed by Lewis acid is investigated. We obtain the N, O-acetal 2-47 after 12 steps from L-glutamatic acid and the total yield is 13%. The results of alkylation of 3-silyloxy-2-acyloxypiperidine 2-47 with a range of silyl enol ethers indicate that the nucleophilic substitution in the presence of BF₃·OEt₂ give the product in cis-diastereoselectivity with high diastereoselectivity (up to 96:4). Based on the results of nucleophilic substitution of 2-47 with silyl enolate, (+)-Febrifugine 2-1, an antimalarial alkaloid, is successfully synthesized.2 On the basis of our previous works on cross-coupling of N-tert-butanesulfinyl imines with aldehyde to form unsymmetrical vicinalβ-amino alcohols, we investigate the situation that the reactant aldehyde is one withγ-carbonyl. The results show that the cross-coupling of aldehyde withγ-carbonyl with N-tert-butanesulfinyl imines goes smoothly in over 80% yield and high diastereoselectivity (dr > 99:1). On the basis of this study, (-)-deoxoprosophylline 3-1 is successfully synthesized.3 Clania variegata Snellen, belonging to Psychidae, is widely distributed in North China, East China and Center China etc. It is one of common insect pests on fruit trees and landscape plants, heavily harming the plants of posaceae, leguminosa, salicaceae, walnut family and platanaceae. The traditional method to prevent and control plant diseases and to eliminate pests is to use pesticide. But it not only strengthens pests' drug resistance, destroys ecological equilibrium, but also makes the accumulation of residue of pesticide in food chain to harm people. Pheromone is once praised as "The Third Generation Pesticide". The major component of the sex pheromone of Paulownia bagworm, Clania variegate was reported to (1'S)-1-ethyl-2-methyl-propyl 3-13-dimethylpentadeca-noate by Gries et al. As to the absolute configuration of this ester, they assigned S configuration to the alcohol part. But the absolute configuration of the two remaining stereogenic centers of the carboxylic acid part, however, has remained unkown. We synthesized the four stereoisomers of 4-1 after 23 steps starting from butyryl chloride. The stereochemistry of the carboxylic acid was constructed under the help of Evans' auxiliaries. The tactile electromagnetic wave analyzer and field trapping experiments are going to be done at appropriate chance. Cl...