作者:Rachel Hevey、Chang-Chun Ling
DOI:10.1016/j.carres.2017.04.007
日期:2017.6
reducing conditions, and the subsequent 6-homologation via Swern oxidation and Wittig olefination to afford a 6,7-dideoxy-β-D-ido-hept-6-enopyranoside. This olefination product was found to adopt predominantly 1C4 conformation in solution by NMR experiments, which places the vinyl group at a more sterically hindered axial position and creates difficulty in subsequent hydroborations.
β-D-异吡喃二糖是令人感兴趣的糖,因为它们在吡喃糖基环中具有异常的构象柔韧性,以及它们的β-1,2-顺式异头构型。在这里,我们报告了我们在还原条件下对4,6-O-亚苄基保护的β-D-吡喃吡喃核苷的区域选择性开环的研究,以及随后通过Swern氧化和Wittig烯化反应进行的6-同源化,得到6,7-二脱氧-β -D-ido-hept-6-enopyranoside。通过NMR实验发现该烯烃化产物在溶液中主要采用1C4构象,该构象将乙烯基置于更受空间阻碍的轴向位置,并在随后的硼氢化反应中产生困难。