Stereoselective syntheses of racemic quercitols and bromoquercitols starting from cyclohexa-1,4-diene: gala-, epi-, muco-, and neo-quercitol
作者:Gökay Aydın、Tahir Savran、Fatih Aktaş、Arif Baran、Metin Balci
DOI:10.1039/c3ob26909d
日期:——
key compound, an isomeric methoxyketal, was prepared by ketalization of 4,5-dibromocyclohexane-1,2-diol with dimethoxypropane followed by the reaction with NaOMe. Deprotection of ketal functionality with sulfuric acid followed by acetylation with acetic anhydride in pyridine resulted in the formation of diacetate rel-(1S,2R,5R)-5-methoxycyclohex-3-ene-1,2-diyl diacetate. Epoxidation of the double bonds
的有效合成晚会- ,外延- ,新- ,和粘膜-quercitols和一些溴化quercitols从开始环己-1,4-二烯被报道。二溴化物的处理,是通过将溴加到环己-1,4-二烯, 和 间氯过苯甲酸 (m -CPBA)生成二溴环氧化物,通过将其处理成功将其转化为所需的二溴二醇 硫酸。所得二醇与2,2-二甲氧基丙烷给予二肢。用NaOMe消除溴化氢得到关键化合物甲氧基缩酮rel-(3a S,5 R,7a S)-5-甲氧基-2,2-二甲基-3a,4,5,7a-四氢苯并[ d ] [1,3]二恶唑。第二个关键化合物,异构体甲氧基缩酮,是通过缩酮化制备的4,5-二溴环己烷-1,2-二醇 和 二甲氧基丙烷然后与NaOMe反应。通过以下方式解除缩酮功能的保护硫酸 然后用 醋酸酐 在 吡啶 导致形成 二乙酸酯rel-(1 S,2 R,5 R)-5-甲氧基环己-3-烯-1,2-二乙酸二酯。异构体甲氧基二乙酸酯