摘要
摘要 本論文主要分為二部份。第一部份為掌性釩錯合物於不對稱催化反應之研究。而第二部份為利用樟腦醯胺衍生之亞胺100進行不對稱串聯反應之研究，以下針對不同反應進行概述： 1) 不對稱動力離析反應: 以容易製備之希夫鹼三牙配位基與VO(acac)2形成之釩錯合物催化不對稱動力離析反應，在1 mol%的催化量，以氯仿為溶劑，反應溫度為0 oC下，可回收51% 具光學活性之亞碸化合物，鏡像選擇性為80%。結合不對稱亞碸化反應與不對稱動力光學離析，可得到鏡像選擇性大於99%之亞碸化合物，產率為70%。 2) 不對稱腈醇反應: 以胺基酸和水楊酸衍生物合成新式五價釩錯合物催化不對稱腈醇反應，發現加入0.5 mol% 之TBAF可加速反應進行，所得之腈醇產物鏡像選擇性為60-91%。 3) 不對稱串聯反應: 以亞胺100對巴豆酸甲酯和2-萘甲醛進行不對稱串聯1,4-加成-醛醇反應，以一鍋化的反應條件下，建立連續4個掌性中心，最好的非鏡像選擇性為94:6，所得之主要產物104b可經由除去掌性輔助基合成多取代之內醯胺化合物107和內酯化合物108。
並列摘要
Abstract This thesis is divided into three parts. The first and second parts deal with a series of chiral vanadium complexes that were prepared with amino alcohols, amino acids and salicylaldehyde derivatives. These chiral complexes have been utilized in the studies of asymmetric kinetic resolution of racemic sulfoxide and the synthesis of cyanohydrins. The third part deals with the application of chiral imine 100 in asymmetric tandem Michael-Aldol reaction. 1) Kinetic resolution of sulfoxide : Simple, inexpensive, preformed vanadium- Schiff base complexes were facilely prepared and used in enantioselective sulfoxidation. Kinetic resolution is observed in the oxidation of racemic sulfoxide using a combination of VO(acac)2 and ligand 36 in chloroform at 0 °C. High enantioselectivity (up to 99% ee) and reasonable yield (70%) was achieved by combining enantioselective sulfoxidation and appropriate concomitant kinetic resolution. 2) Asymmetric cyanohydrin synthesis: In the presence of amino acids and salicylaldehyde derivatives, new vanadium complexes were found to catalyse the asymmetric addition of trimethylsilyl cyanide to aldehydes. Under optimised conditions, enantioselectivities of 60–91% were obtained using 5 mol % of the catalyst. 3) Asymmetric tandem reaction: Michael addition of enolate of imine 100 derived from glycinate and ketopinic amide to ,- unsaturated esters and subsequent Mukaiyama Aldol reaction with aldehydes afforded the corresponding products 104b and 104d with 94:6 de in one pot reaction conditions. Hydrolysis of major products 104b gave multisubstituted - lactams and - lactones consisted of consecutive four stereogenic centers with high enantiomeric excesses.