Access to Oxetane-Containing <i>psico</i>-Nucleosides from 2-Methyleneoxetanes: A Role for Neighboring Group Participation?
作者:Yanke Liang、Nathan Hnatiuk、John M. Rowley、Bryan T. Whiting、Geoffrey W. Coates、Paul R. Rablen、Martha Morton、Amy R. Howell
DOI:10.1021/jo201565h
日期:2011.12.16
of the powerful antiviral natural product, oxetanocin A, has been readily synthesized from cis-2-butene-1,4-diol. Key 2-methyleneoxetane precursors were derived from β-lactones prepared by the carbonylation of epoxides. F+-mediated nucleobase incorporation provided the corresponding nucleosides in good yield but with low diastereoselectivity. Surprisingly, attempted exploitation of anchimeric assistance
强大的抗病毒天然产物的第一个psico- oxetanocin类似物,oxetanocin A,很容易从顺-2-丁烯-1,4-二醇合成。关键的2-亚甲基氧杂环丁烷前体衍生自通过环氧化物羰基化制得的β-内酯。F +介导的核苷碱基掺入以良好的产率提供了相应的核苷,但非对映选择性低。出人意料的是,尝试利用邻氨基苯甲酸辅助来增加选择性并没有取得成果。制备了一系列的2-亚甲基氧杂环丁烷和相关的2-亚甲基四氢呋喃底物,以探索其基础。除了一个例外,这些底物在核碱基掺入中也显示出很少的立体选择性。进行了计算研究,以检验涉及融合的[4.2.0]或[4.3.0]中间体的邻近小组的参与是否有利。