An Access to the 尾-Anomer of 4鈥?Thio-C-ribonucleosides: Hydroboration of 1-C-Aryl- or 1-C-Heteroaryl-4-thiofuranoid Glycals and Its Regiochemical Outcome

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• 作者：Kazuhiro Haraguchi ; Chikafumi Horii ; Yuichi Yoshimura ; Fumiko Ariga ; Aya Tadokoro ; Hiromichi Tanaka
• 刊名：Journal of Organic Chemistry
• 出版年：2011
• 出版时间：November 4, 2011
• 年：2011
• 卷：76
• 期：21
• 页码：8658-8669
• 全文大小：1139K
• 年卷期：v.76,no.21(November 4, 2011)
• ISSN：1520-6904

文摘

We have developed a novel method for the synthesis of the 尾-anomer of 4鈥?thio-C-ribonucleosides from 3,5-O-(di-tert-butylsilylene)-4-thiofuranoid glycal. Palladium-catalyzed coupling of 1-tributylstannyl-4-thiofuranoid glycal with iodobenzene or a heteroaryl halide gave 1-C-phenyl- or 1-C-heteroaryl-glycals. Hydroboration of these glycals proceeded at the 伪-face, and subsequent alkaline hydrogen peroxide treatment of the resulting 2鈥?伪-borane furnished the respective 尾-anomer of 4鈥?thio-C-ribonucleosides. These results demonstrate that this synthetic method has a wider scope in terms of heterocyclic base structure. During this study, unexpected Markovnikov-oriented hydroboration has been observed to lead to the respective 1鈥?伪-boranes. These 1鈥?boranes were converted into either the ring-opened structure or the 2鈥?deoxy derivatives depending upon their stability.