作者:Frank Tranel、Günter Haufe
DOI:10.1016/j.jfluchem.2004.09.001
日期:2004.11
yields. These [3,3]-sigmatropic rearrangements are diastereoselective giving trans-configured double bonds, exclusively. Corresponding esters derived from (Z)-2-fluorocyclododec-2-enol (22), did rearrange to yield mixtures of diastereomers much less selectively. Also 2-fluorodec-2-enol (6), which was prepared by rearrangement of 2-fluoro-2-octyloxirane (5) with TMSOTf and triethylamine, was successfully
2-氟烷基-1-烯-3-醇(4),可通过溴氟化从末端烯烃(1)中获得,随后将1-溴-2-氟烷烃(2)脱氢溴化以形成2-氟烯烃(3)和二氧化硒用叔丁基氢过氧化物介导的烯丙基氧化,在用原乙酸三甲酯处理后进行Johnson-Claisen重排,以高收率得到4-氟烷-4-烯酸甲酯(7)。相反,爱尔兰-克莱森在乙醚中用三乙胺和TMSOTf进行的3-乙酰氧基-2-氟癸-1-烯(9b)重排失败。取代预期的羧酸形成,α位到羧基的选择性C-甲硅烷基化形成14发生。然而,爱尔兰-克莱森重排成功了,将四个2-氟代烷基-1-en-3-醇(4)中相应的氯乙酸酯10和丙酸酯11生成了2-氯-4-氟代烷-4-烯羧酸(15)或其2-甲基衍生物16分别以中等收率获得。这些[3,3] -sigmatropic重排是非对映选择性的,仅给出反式构型的双键。衍生自(Z)-2-氟环十二烷基-2-烯醇(22)的相应的酯确实重排以产生非