little or no interference with disaccharide synthesis at the nearby O-4 atom. Conformations of both cis - and trans -fused types of 4,6-cyclic sulfates are discussed. At an unsubstituted anomeric center, the course of reaction by phenyl chlorosulfate is determined by neighboring-group participation possibilities, and the strong leaving-group affinity of a phenylsulfate substituent. This is demonstrated
摘要在
苯基
氯硫酸氢钠与不含OH-4和OH-6的化合物的反应中,例如在
甲基2,3-二-O-
苄基醛基
吡喃
吡喃糖苷中,伯羟基发生区域选择性取代,或者4,取决于实验条件,形成6-环
硫酸盐。向二-O-
苄基糖苷中添加6-(
苯硫酸盐)取代基似乎几乎不干扰或几乎不干扰附近的O-4原子处的二糖合成。讨论了4,6-环
硫酸盐的顺式和反式融合形式的构象。在未取代的异头异构中心,
氯硫酸苯酯的反应过程取决于相邻基团的参与可能性以及
苯硫酸酯取代基的强离去基团亲和力。2-乙酰
氨基-4的60%转化证明了这一点,