Rhodium(II)-catalyzed decomposition of 3-O-(2-diazo-2-phenylacetyl)-1,2;5,6-di-O-isopropylidene-α-d-allofuranose: diastereoselective ether formation
作者:Iulia A. Sacui、Matthias Zeller、Peter Norris
DOI:10.1016/j.carres.2008.04.005
日期:2008.7
Standard diazo transfer to 3-O-(2-phenylacetyl)-1,2;5,6-di-O-isopropylidene-alpha-d-allofuranose (2), using p-acetamidobenzenesulfonyl azide (p-ABSA, 3) and DBU as base, provides the expected 3-O-(2-diazo-2-phenylacetyl)-1,2;5,6-di-O-isopropylidene-alpha-D-allofuranose (4) as an orange syrup in 49% isolated yield. Subsequent decomposition of 4 using Rh(2)(OAc)(4) yields ether 5 in a highly diastereoselective
使用对乙酰氨基苯磺酰叠氮(p-ABSA,3)和以DBU为基础,以49%的橙色糖浆形式提供预期的3-O-(2-重氮-2-苯基乙酰基)-1,2; 5,6-二-O-异亚丙基-α-D-呋喃糖(4)孤立的产量。随后使用Rh(2)(OAc)(4)分解4以高度非对映选择性的方式生成醚5,分离出的产率为58%。X射线晶体结构5证明两个新产生的立体中心均具有(S)构型;呋喃糖环5的O-3处酯基的构象用于讨论观察到的立体选择性的可能原因。