A facile formation of 2,5-anhydro sugars by ring contraction in methyl hexopyranoside 2-triflates under conditions of nucleophilic displacement
作者:Hans H. Baer、Fernando Hernández Mateo、Lisa Siemsen
DOI:10.1016/0008-6215(89)80056-4
日期:1989.4
hexopyranoside. The reaction is discussed in light of a literature survey of the chemical behavior of hexopyranoside 2-sulfonates in general, and 2-triflates in particular. Direct SN2 displacements, eliminations, and such different kinds of rearrangement as have previously been observed with structural analogs were not encountered in the present study. However, there is some precedent, in hexopyranoside
在温和条件下,甲基3,4-O-异亚丙基-2-O-(三氟甲基磺酰基)-α-L-复写糖苷与多种亲核试剂的反应导致三氟甲磺酸酯基团的取代,以及将环氧原子连接至C-2并亲核试剂进入C-1,可得到2,5-脱水糖衍生物的良好收率。所用试剂是氟化氢-三乙胺络合物,在碳酸氢钠,苯甲酸钠,叠氮化钠,硫氰酸钾和硼氢化钠存在下的甲醇。在甲基4-O-苄基-3-O-(4-甲氧基苄基)-2-O-(三氟甲基磺酰基)-α-ha-L-呋喃核糖苷和甲基4,6-二脱氧-甲基中也发生了相同类型的取代环收缩。 3-O-(4-甲氧基苄基)-2-O-(三氟甲基磺酰基)-α-L-木基己吡喃糖苷。一般根据己吡喃糖苷2-磺酸盐,特别是2-三氟甲磺酸酯的化学行为的文献综述讨论该反应。在本研究中未遇到直接的SN2置换,消除以及先前用结构类似物观察到的不同种类的重排。然而,对于己吡喃糖苷2-三氟甲磺酸,有一些先例可以发现此处研究的四位代表容易进行