| Summary: | 博士 === 國立臺灣師範大學 === 化學系 === 102 === Abstract
The research work presented in this dissertation is highlighted the importance of nitrogen containing chiral compounds its synthesis through various methods. Thesis is divided into four chapters as mentioned below.
Chapter 1. General Introduction
This chapter deals with the importance of nitrogen containing chiral compounds in nature and in human life. Importance of amino acids, peptides, chiral drug molecules in pharmaceuticals and as a chiral ligands used for asymmetric reactions.
Chapter 2. Preparation of Chiral -Substituted Alaninates Through an Efficient Diastereoselective Synthesis of Tri-substituted Allylic Alcohols.
In this part we have discussed the addition of vinylaluminium reagents, produced by the zirconium catalyzed carboalumination of various alkynes and Me3Al, to the easily accessible aldehyde (3) afforded the corresponding trisubstituted allylic alcohols with excellent diastereoselectivities. A subsequent Overman reaction led to an efficient and highly stereoselective construction of allylic amines containing chiral quaternary carbon stereocentres. The utility of this method was demonstrated for the synthesis of chiral -Substituted Alaninates.
Chapter 3. Highly Enantioselective Rh-Catalyzed Alkenylation of Imines: Synthesis of Chiral Allylic Amines via Asymmetric Addition of Potassium Alkenyltrifluoroborates to N-Tosyl Imines.
Simple N-tosyl aryl aldimines, prepared from the condensation of para tolyl sulfonylamide and aromatic aldehydes, can be used as substrates in the rhodium catalyzed 1,2- addition reaction using alkenyl boron nucleophiles. In the presence of 1.5 mol % of [RhCl(29f)]2, enantioselective addition of various potassium alkenyltrifluoroborates to various aryl aldimines furnished the corresponding chiral allylic amines in good yields and good to excellent ee.
Chapter 4. Microwave-Assisted Enantioselective Addition of Potassium alkenyl trifluoroborates to aldimines catalyzed by Rh/diene catalyst.
In this part we have reported our recent studies on microwave assisted asymmetric reaction. Use of simple N-protected simple aryl aldimines and its addition with alkenyl potassium trifluoroborates. Preparation of chiral allylic amines was achieved in presence of chiral catalyst which was in situ generated using 0.5 mol % of [RhCl(C2H4)2]2 and Ligand 29e (1.2 mol %) with moderate to high yield (40-96%), and 86-98% ee.
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