Tricyclic furanoid dichloroacetyl orthoesters of -mannose from 1,2-O-trichloroethylidene-β--mannofuranose

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• 作者：Gü ; l Salman ; Yesim ; K&ouml ; k ; G&ouml ; khan ; Yü ; ceer ; Levent
• 关键词：Sugar acetals ; Sugar orthoesters ; Trichloroethylidene acetals ; Glycosylation
• 刊名：Carbohydrate Research
• 出版年：2004
• 出版时间：July 12, 2004
• 年：2004
• 卷：339
• 期：10
• 页码：1739-1745
• 全文大小：289 K

文摘

1,2-O-(R)-Trichloroethylidene-β-d-mannofuranose (1) was obtained from the reaction of d-mannose with chloral. Reaction of 1 with potassium tert-butoxide (3Mequiv) gave the thermodynamically stable 1,2,5-O-orthodichloroacetyl-β-d-mannofuranose as the sole product whereas 1.5Mequiv of reagent gave the kinetically controlled 1,2,3-O-orthodichloroacetyl-β-d-mannofuranose (10) as the main product. Orthoester 10 gave the 5,6-isopropylidene derivative, which was also obtained from the reaction of 5,6-O-isopropylidene-1,2-O-(R)-trichloroethylidene-β-d-mannofuranose with potassium tert-butoxide (1.5Mequiv). These novel orthoesters are expected to prove useful as protecting groups and as building blocks in the formations of new mannofuranisidic units.