Synthesis of 4,6-Dideoxyfuranoses through the Regioselective and Diastereoselective Oxyfunctionalization of a Dimethylphenylsilyl-Substituted Chiral Homoallylic Alcohol
作者:Waldemar Adam、Chantu R. Saha-Möller、Katharina S. Schmid
DOI:10.1021/jo010549w
日期:2001.11.1
photooxygenation, metal-catalyzed epoxidation, and oxidative desilylation. Photooxygenation of the hydroxy vinylsilane 1 and subsequent triphenylphosphine reduction of the hydroperoxides 3 afford the like-4a and unlike-4b diols, which have been converted separately to the tetrahydrofurans (2S*,3R*,5R*)-7a and (2S*,3R*,5S*)-7b by a combination of diastereoselective epoxidation and regioselective intramolecular
通过从容易获得的E-5-二甲基苯基甲硅烷基-2-己烯-4-醇(1)开始并依次采用三种通用的氧官能化方法(即光氧化,金属催化的环氧化,和氧化去甲硅烷基化。羟基乙烯基硅烷1的光氧化作用和氢过氧化物3的三苯基膦还原反应得到类似的4a和不同于4b的二醇,它们已分别转化为四氢呋喃(2S *,3R *,5R *)-7a和(2S *, 3R *,5S *)-7b通过非对映选择性环氧化和区域选择性分子内环氧化物开环的组合。在环氧化反应中,由Ti(OiPr)(4)或VO(acac)(2)催化,仅得到环氧化物5的一种非对映异构体(dr> 95:5)。erythro-5中环氧环的进一步分子内打开在C-alpha位置区域选择性地发生,并且在甲硅烷基取代的立体异构中心构型的反转下非对映选择性地发生,从而仅产生四取代的四氢呋喃中的一个非对映异构体7。迄今未知的4,6-二脱氧呋喃糖酶10a和10b。光学活性的E-5-二