Synthesis Of Several Optically Active Chiral Intermediates

Chirality is a fundamental property of the nature. Optically active chiral compounds play an important role in many fields. The increasing demand to produce enantiomerically pure Pharmaceuticals, agrochemicals, eatables, flavors, and other fine chemicals has advanced the field of chiral technologies. Chirality is of prime significance, as most of the biological macromolecules of living systems occur in nature in one enantiomeric form only. The two enantiomers may have unequal degrees or different kinds of activities. One may be therapeutically effective, while the other may be ineffective or even toxic. Among the chiral agochemicals, it is very often that only one of the enantiomers has effect of weeding, killing insects or sterilizing; however, the others are not only ineffective to the pests and weeds but also they may pollute the environment for their toxicity. In the material science field, the function of the chiral macromolecule material is relation to their stereo-structure. Different structure has different properties, such as different melting point, the mechanical function, optical function, electrical function , et al. At the food realm, the food that people rely on to live is constituted with the optical material basically. At the spice realm, different enantiomericform has different flavor. Therefore, the optical compound has a very big market potential, attracting the people to carry out the thorough research.The method to acquire the chiral compound mainly has five kinds, namely natural withdraw, the living creature ferment, racemate resolution, chiral pool synthesis, asymmetric synthesis. Natural withdraw method is direct from the living creature to acquire the chiral compound. The living creature ferment method is to adopt the germ to make the substrate convert to the optical active compound. The resolution of racemates is to separate the racemate to single isomer with the physical, chemical or biologic method, and it is divided into following several kinds again: choice adsorb resolution, crystallize resolution, chemistry resolution, dynamics resolution, chiral chromatography resolution, extraction resolution, enzyme resolution etc. The chiral pool synthesis method involve the conversion or derivatization of readily available natural chiral compounds (chiral pools) to acquire new chiral compound. Asymmetric synthesis refers to the conversion of an achiral starting material to a chiral product in a chiral environment. It is presently the most powerful and commonly used method for chiral molecule preparation.The research work in this thesis is divided into two parts. In the first part ,we focous on synthesizing several optically active β -aminoalcohol possesing important application in preparation of chiral drugs. There is at least five kinds of methods to have been reported, but they have some shortcomings not to satisfy our demands. Chiral β -aminoalcohol were synthesized by four steps from L-proline as raw material: esterization, protection of amino-group, Grignard reaction and catalytic hydrogenolysis with total yield 46%. The structure of N-benzyl- β -aminoalcohol and β-aminoalcohol were confirmed by melting point, ~1H NMR, specific rotation and elemental analysis, and were...