Preparation of isoborneol oxazaborolidines and their application to reduction of prochiral ketones

• Main Authors: Yi-Hsuan Lu, 呂怡萱
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/t4me5s

碩士 === 朝陽科技大學 === 應用化學系碩士班 === 91 === Abstract In order to obtain an excellent and cheaper chiral ligand for borane reduction, we have synthesized the new 1,2-amino alcohols (compounds 46 and 49) starting from camphor, which is an inexpensive and readily available natural product. The two stereoisomers of hydroxymethyl isoborneols (compounds 42 and 43) were prepared first. Then, compounds 42 and 43 were converted to aminomethyl isoborneols 46 and 49, which are the 1,2-amino alcohols. All of the isoborneol derivatives were then converted to oxazaborolidines 1、2、3 and 4. These oxazaborolidines were evaluated as chiral catalysts for the enantioselective reduction of prochiral ketones. Under the best experimental condition（30 mol% catalyst, THF, r.t ）, a 98% yield of (S)-1-phenylethanol of 72% ee was obtained in the borane reduction of acetophenone.