A Modular Approach to Aryl-C-ribonucleosides via the Allylic Substitution and Ring-Closing Metathesis Sequence. A Stereocontrolled Synthesis of All Four 伪-/尾- and d
详细信息 查看全文
- 作者：Jan S虒tambasky虂 ; Vojte虒ch Kapras ; Martin S虒tefko ; Ondr虒ej Kysilka ; Michal Hocek ; Andrei V. Malkov ; Pavel Koc虒ovsky虂
- 刊名：Journal of Organic Chemistry
- 出版年：2011
- 出版时间：October 7, 2011
- 年：2011
- 卷：76
- 期：19
- 页码：7781-7803
- 全文大小：1522K
- 年卷期：v.76,no.19(October 7, 2011)
- ISSN：1520-6904
文摘
Iridium(I)-catalyzed allylation of the enantiopure monoprotected copper(I) alkoxide, generated from (S)-5a, with the enantiopure allylic carbonates (R)-9a,b has been developed as the key step in a new approach to C-nucleoside analogues. The anomeric center was thus constructed via a stereocontrolled formation of the C鈥揙 rather than C鈥揅 bond with retention of configuration. The resulting bisallyl ethers 15a,b (鈮?0% de and >99% ee) were converted into C-ribosides 29a,b via the Ru-catalyzed ring-closing metathesis, followed by a diastereoselective dihydroxylation catalyzed by OsO4 or RuO4 and deprotection. Variation of the absolute configuration of the starting segments 5a and 9a,b allowed a stereocontrolled synthesis of all four 伪/尾-d/l-combinations.