Highly Stereoselective Total Syntheses of 2,5-Anhydro-4-deoxy-D-ribo-hexonic Acid and of (1S)-1-C-(6-amino-7H-purin-8-yl)-1,4-anhydro-3-deoxy-D-erythro-pentitol (= cordycepin C)
作者:Fabrizio Gasparini、Pierre Vogel
DOI:10.1002/hlca.19890720211
日期:1989.3.15
Highly regio- and stereoselective monohydroxylation of the CC bond of (+)-7-oxabicyclo[2.2.1]hept-5-en-2-one (8) was achieved via LiAlH4 reduction of the corresponding 5,6-exo-epoxy dimethyl acetal 9. The reaction gave exclusively (–)-(1R, 2R, 4S)-6,6-dimethoxy-7-oxabicyclo[2.2.1]heptan-2-exo-ol (10) which was transformed into 2,5-anhydro-3-O-benzyl-4-deoxy-D-ribo-hexonic acid (15) and 2,5-anhydro
高度区域选择性和的C-C键(+)立体选择性monohydroxylation - 7-氧杂二环[2.2.1]庚-5-烯-2-酮(8)中的溶液来实现经由的LiAlH 4还原相应的5,6-的外切-环氧二甲基乙缩醛9。反应仅产生(-)-(1 R,2 R,4 S)-6,6-二甲氧基-7-氧杂双环[2.2.1]庚烷-2- exo -ol(10),将其转化为2,5 -anhydro -3- ö苄基-4-脱氧-D-核糖-hexonic酸(15)和2,5-脱水-4-脱氧-D-核糖-hexonic酸(6)通过(–)-(1 R,4 S,6 R)-6-外-苄氧基-2-[((叔丁基)二甲基甲硅烷基]氧基} -7-氧杂双环[2.2.1]庚-2-烯的臭氧分解(14)。使用CsF / DMF从6和4,5,6-三氨基嘧啶衍生出虫草素C(5),以产生腺嘌呤杂环。