作者:Tony K.M Shing、Yiu C Leung、Kwan W Yeung
DOI:10.1016/s0040-4020(03)00145-5
日期:2003.3
Four l-erythro-2-uloses were readily prepared from l-arabinose via a reaction sequence involving Fischer glycosidation, acetalization and oxidation. Bulky steric sensors at the anomeric center could enhance the stereoselectivity of the dioxirane epoxidation and one of the uloses performed with good enantioselectivity towards trans-stilbene (up to 90% ee). However, the catalysts decomposed during the
四个1-赤-2- uloses从L-阿拉伯糖通过涉及费歇尔糖苷化,缩醛化和氧化的反应序列中容易地制备。在异头异构中心的庞大空间传感器可以增强二环氧乙烷环氧化的立体选择性,并且其中一种对高二苯乙烯的对映体选择性(最高90%ee)。然而,在碱性条件下,环氧化过程中催化剂分解,最大化学收率仅为13%。三1-苏-3-果糖可以克服酯基团α对酮官能团的吸电子作用而产生的分解问题。使用带有两个侧酯基的酮,最佳化学收率可达93%。一种改进的果糖对反式二取代和三取代的烯烃表现出中等的对映选择性(40-68%ee)。