A ring-closing metathesis based synthesis of bicyclic nucleosides locked in S-type conformations by hydroxyl functionalised 3′,4′-trans linkages
作者:Morten Freitag、Helena Thomasen、Nanna K Christensen、Michael Petersen、Poul Nielsen
DOI:10.1016/j.tet.2004.03.019
日期:2004.4
introduced in this nucleoside reveals a large potential for further derivatisation, and as the first example, a stereoselective dihydroxylation followed by deprotection afforded a multihydroxylated bicyclic nucleoside. The configuration and conformational behaviour was determined by NMR spectroscopy and ab initio calculations, and both this bicyclic nucleoside and its unsaturated analogue were found to
[4.3.0]双环核苷,含有不饱和羟基化的3',4'-反式链接已被有效地合成。因此,以双丙酮-d-葡萄糖为起始原料,用于烯丙基的立体选择性格氏反应,核碱基偶联以及随后的闭环复分解(RCM)反应被用作关键反应。引入该核苷中的环己烯部分显示出进一步衍生化的巨大潜力,并且作为第一个实例,立体选择性二羟基化然后脱保护得到了多羟基化的双环核苷。通过NMR光谱和从头算来确定构型和构象行为,并且发现该双环核苷及其不饱和类似物都强烈地受S-型构象的限制。