Solvent Effect Observed in Nucleophilic Substitution of 4′-(Benzoyloxy)cordycepin with AlMe3: Stereochemical Evidence for SNi Mechanism
详细信息 查看全文
- 作者：Yutaka Kubota ; Mayumi Kunikata ; Kazuhiro Haraguchi ; Hiromichi Tanaka
- 刊名：Journal of Organic Chemistry
- 出版年：2009
- 出版时间：May 1, 2009
- 年：2009
- 卷：74
- 期：9
- 页码：3402-3405
- 全文大小：141K
- 年卷期：v.74,no.9(May 1, 2009)
- ISSN：1520-6904
文摘
Nucleophilic substitution between the 4′-benzoyloxy derivative of cordycepin (3′-deoxyadenosine) and AlMe3 proceeds mostly with retention of configuration at the 4′-position: the 4′-benzoyloxy substrate having the β-d-configuration (8a) gave the 4′-methylated β-d-nucleoside (9a) with a high diastereomeric excess, while the substrate 8b having the opposite 4′-configuration gave the corresponding α-l-isomer (9b) with a comparatively lower stereoselectivity. The SNi mechanism is proposed for this reaction (from 8 to 9). The polarity of the solvent has a significant influence on the stereoselectivity, especially for the formation of 9b.