Reaktionen mit und in wasserfreiem Fluorwasserstoft 7.<sup>1</sup>Von Isopropylidenzuckern zu acylierten Pyranosyl- oder Furanosylfluoriden in einem Schritt
作者:Ralf Miethchen、Torsten Gabriel、Gundula Kolp
DOI:10.1055/s-1991-26601
日期:——
Reactions with and in Anhydrous Hydrogen Fluoride 7.1 From Isopropylidene Sugars to Acylated Pyranosyl and Furanosyl Fluorides in One Step A convenient one-pot transformation of the 6-O-substituted 1,2:3,4-di-O-isopropylidene-α-D-galactopyranoses 1a-g and the 3-O-substituted 1,2:5,6-di-O-isopropylidene-α-D-glucofuranoses 5a-c is described to form the corresponding 6-O-substituted 2,3, 4-tri-O-acyl-α-D-galactopyranosyl fluorides 2a-f, 3e, 3g and 3-O-substituted 2,5,6-tri-O-acetyl-α/β-D-glucofuranosyl fluorides 6a-c, respectively. This short way of synthesis is possible by use of the new homogeneous reagent/catalyst/solvent combination composed of anhydrous hydrogen fluoride/nitromethane/carboxylic acid anhydride (2: 5:1-1.5). A ring contraction or extension is not found; in addition the functional groups are regiostable in 6-position of 2a-f, 3e, 3g and in 3-position of 6a-c, respectively.
与无水氟化氢的反应 7.1 从异丙基糖到酰化吡喃糖和呋喃糖氟化物的一步法 一种便捷的单锅转化方法被描述,用于将6-O-取代的1,2:3,4-二-O-异丙基化α-D-半乳糖吡喃糖(1a-g)和3-O-取代的1,2:5,6-二-O-异丙基化α-D-葡萄糖呋喃糖(5a-c)转化为相应的6-O-取代的2,3,4-三-O-酰化α-D-半乳糖吡喃糖氟化物(2a-f, 3e, 3g)以及3-O-取代的2,5,6-三-O-乙酰化α/β-D-葡萄糖呋喃糖氟化物(6a-c)。这种简短的合成方法得益于新的均相试剂/催化剂/溶剂组合,包含无水氟化氢/硝基甲烷/羧酸酐(2:5:1-1.5)。未发现环收缩或扩展;此外,功能基团在2a-f, 3e, 3g的6位和6a-c的3位均表现出区域稳定性。