Alternative Syntheses of L-(-)-Oleandrose from L-Rhamnose1Preparation of Glycals
摘要:
L-Rhamnal (2) is prepared from L-rhamnose (3) by use of an improved generalized Fischer-Zach reaction. L-Rhamnal (2) is then converted to L-(-)-oleandrose (1) by stannylene mediated selective methylation and effective hydration. Benzyl alpha-L-oleandrose (12) is prepared by selective methylation and deoxygenation of L-rhamnose (3).
A convenient, high-yield synthesis of l-oleandrose and l-oleandral
作者:Richard L. Tolman、Louis H. Peterson
DOI:10.1016/0008-6215(89)84090-x
日期:1989.6
-arabino-hexose) from l -arabinose has been achieved. The synthesis is satisfactory for large-scale preparation of oleandrosylating intermediates, and employs dithiolane formation for protection of the aldehyde group during deoxygenation and methylation steps, and Wittig chain-extension to 2-deoxyhexose derivatives. Useful intermediates in the introduction of oleandrose glycosides into natural products
Avermectin (AVM) refers to eight macrolides containing a common l-oleandrosyl disaccharide chain indispensable to their antiparasitic bioactivities. We delineated the biosynthetic pathway of TDP-β-l-oleandrose (1), the sugar donor of AVM, by characterizing AveBVIII, AveBV, and AveBVII as TDP-sugar 3-ketoreductase, 5-epimerase, and 3-O-methyltransferase, respectively. On the basis of this pathway, we
Avermectin (AVM) 是指八种大环内酯类化合物,含有对其抗寄生虫生物活性必不可少的常见l-夹竹桃基二糖链。我们划定TDP-β的生物合成途径-l -oleandrose(1),AVM的糖供体,通过表征AveBVIII,AveBV和AveBVII作为TDP-糖-3-酮还原酶,5差向异构酶,和3- Ò -methyltransferase,分别。在这个途径的基础上,我们成功重组的生物合成1的大肠杆菌。我们的工作完成了AVM的生物合成途径,为进一步的研究奠定了坚实的基础。
Synthese der L-Oleandrose. Desoxyzucker, 21. Mitteilung
作者:F. Blindenbacher、T. Reichstein
DOI:10.1002/hlca.19480310721
日期:——
Die Synthesedes 2-Desoxy-L-glucomethylose-3-methylathers wird beschrieben. Der Bucker wurde krystallisiert erhalten und erwies sich als identisch mit natürlicher Oleandrose aus Oleandrin.
由苯丙氨酸酯合成2-脱氧-L-葡萄糖甲基糖-3-甲基酯。Der Bucker wurde krystallisiert erhalten and erwies sich als identisch mitnatürlicherOleandrose aus Oleandrin。
Stereocontrolled Synthesis of the Fully Glycosylated Monomeric Unit of Lomaiviticin A
作者:Zhi Xu、Mikaela DiBello、Zechun Wang、John A. Rose、Lei Chen、Xin Li、Seth B. Herzon
DOI:10.1021/jacs.2c07631
日期:2022.9.7
We describe a stereocontrolledsynthesis of 3, the fully glycosylated monomeric unit of the dimeric cytotoxic bacterial metabolite (−)-lomaiviticin A (2). A novel strategy involving convergent, site- and stereoselective coupling of the β,γ-unsaturated ketone 6 and the naphthyl bromide 7 (92%, 15:1 diastereomeric ratio (dr)), followed by radical-based annulation and silyl ether cleavage, provided the
α-selective glycosylation using l-oleandrose, a 2-deoxysugar that is frequently found in natural products, and its application to the totalsynthesis of the natural cardiotonic steroids oleandrin and beaumontoside. To improve the reaction diastereoselectivity and to minimize side-product formation, an extensive evaluation and optimization of the conditions leading to α-selective glycosylation of digitoxigenin