Synthesis and Conformational Investigation of Methyl 4a-Carba-<scp>d</scp>-arabinofuranosides
作者:Christopher S. Callam、Todd L. Lowary
DOI:10.1021/jo010827r
日期:2001.12.1
synthesis of both targets. Through the use of NMR spectroscopy, we have probed the ring conformation of 3 and 4, as well as the rotamer populations about the C(4)-C(5) and C(1)-O(1) bonds. These studies have demonstrated that there are differences in ring conformation between these carbasugars and their glycoside parents (1 and 2). However, only minor differences are seen in the rotameric equilibrium about
据报道,合成了甲基α-D-阿拉伯呋喃糖苷和甲基β-D-阿拉伯呋喃糖苷的羧甲醚类似物(3和4)。开发的途径涉及将D-甘露糖转化为适当保护的二烯(13),然后通过烯烃复分解环化。将所得的环戊烯(14)进行立体选择性氢化,以提供可用于合成两个靶的中间体。通过使用核磁共振波谱学,我们已经探测了3和4的环构象,以及关于C(4)-C(5)和C(1)-O(1)键的旋转异构体。这些研究表明,这些Carcarbugars和其糖苷亲本之间的环构象存在差异(1和2)。但是,在相对于1和2的3和4中,C(4)-C(5)键的旋转异构平衡中只有很小的差异。关于C(1)-O(1)键,来自3和4的NOE数据表明,关于该键的偏爱位置与糖苷中的偏爱位置相似。也就是说,甲基是抗C(2)的。但是,通过测量甲基与C(2)或C(4a)之间的(3)J(C,C)不能确定这种偏好。