Department of Chemistry, University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria.
Org Lett. 2017 Jan 6;19(1):78-81. doi: 10.1021/acs.orglett.6b03358. Epub 2016 Dec 23.
Stereoselective synthesis of variably protected α- and β-l-Ara4N glycosyl H-phosphonates as key intermediates in the syntheses of β-l-Ara4N-modified LPS structures and α-l-Ara4N-containing biosynthetic precursors is reported. A facile one-pot approach toward β-l-Ara4N glycosyl H-phosphonates includes anomeric deallylation of protected 4-azido β-l-Ara4N via terminal olefin isomerization followed by ozonolysis and methanolysis of formyl groups to furnish exclusively β-configured lactols that are phosphitylated with retention of configuration. The carbohydrate epitope of β-l-Ara4N-modified Lipid A, βGlcN(1→6)αGlcN(1→P←1)β-l-Ara4N, was stereoselectively synthesized and linked to maleimide-activated bovine serum albumin.
报道了作为β-l-Ara4N 修饰 LPS 结构和α-l-Ara4N 生物合成前体合成关键中间体的各种保护的α-和β-l-Ara4N 糖基 H-膦酸酯的立体选择性合成。一种简便的一锅法制备β-l-Ara4N 糖基 H-膦酸酯包括通过末端烯烃异构化使保护的 4-叠氮-β-l-Ara4N 去烯丙基化，然后进行臭氧分解和甲酰基的甲醇解，仅得到保留构型的β-构型内酯，然后用构型保持的方式将其膦酰化。β-l-Ara4N 修饰的脂 A 的碳水化合物表位βGlcN(1→6)αGlcN(1→P←1)β-l-Ara4N 被立体选择性合成并连接到马来酰亚胺活化的牛血清白蛋白上。
