Preparation of 2-Ethoxy-3-hydroxy-4-(perfluoroalkyl)tetrahydropyran Derivatives from Substituted 4-Ethoxybut-3-en-1-ols
作者:Stig Valdersnes、Leiv K. Sydnes
DOI:10.1002/ejoc.200900687
日期:2009.11
as the only product, 6-substituted and 6,6-disubstituted 2-ethoxy-4-(perfluoroalkyl)tetrahydropyran-3-ones in 77–100 % yield as stereoisomeric mixtures. Subsequent reduction of the keto group with sodium borohydride in ethanol was uneventful and completed the syntheses of a range of 4-perfluorobutylated tetrahydropyran derivatives; the yields in this step were in the 81–94 % range. The best result was
许多 1-取代和 1,1-二取代 (E)-4,5,5-triethoxypent-3-en-1-ols (1) 已被 1-碘全氟烷烃以选择性方式转化为全氟烷基化四氢呋喃和四氢吡喃使用连二亚硫酸钠 (Na2S2O4) 作为自由基引发剂在自由基条件下添加。1 的直接全氟烷基化仅得到前一种产物,产率适中 (50–75%),但当 1 转化为相应的 6-取代和 6,6-二取代 2,3-二乙氧基-5,6-二氢-进行全氟烷基化之前的 2H-吡喃,结果证明转化明显更成功,并且作为唯一的产物,6-取代和 6,6-二取代的 2-乙氧基-4-(全氟烷基)四氢吡喃-3-酮在77–100% 的立体异构混合物产率。随后在乙醇中用硼氢化钠还原酮基并顺利完成了一系列 4-全氟丁基化四氢吡喃衍生物的合成;这一步的产率在 81-94% 的范围内。最好的结果是用 (E)-2-methyl-5,6,6-triethoxyhex-4-en-2-ol