Synthesis and Heck Reactions of Ethenyl- and (Z)-Butadien-1-yl Nonaflate Obtained by the Fragmentation of Furan Derivatives
作者:Ilya M. Lyapkalo、Matthias Webel、Hans-Ulrich Reißig
DOI:10.1002/1099-0690(200111)2001:22<4189::aid-ejoc4189>3.0.co;2-i
日期:2001.11
(1b) and (Z)-buta-1,3-dien-1-yl nonaflate (2) in good yields. The required enolates were obtained by aldehyde-free routes by the lithiation of tetrahydrofuran or 2,5-dihydrofuran followed by the cyclofragmentation of the metallated heterocycles. The application of this approach to the synthesis of allenyl nonaflate 3 failed, presumably due to the intrinsic instability of this allene derivative. The nonaflates
烯醇锂或甲硅烷基烯醇醚(形式上衍生自乙醛或巴豆醛)与九氟丁烷磺酰氟的九氟烷磺化以良好的收率得到九氟乙炔酯 (1b) 和 (Z)-buta-1,3-dien-1-yl nonaflate (2) . 通过四氢呋喃或 2,5-二氢呋喃的锂化,然后是金属化杂环的环断裂,通过无醛途径获得所需的烯醇化物。将这种方法应用于合成丙二烯基壬二酸酯 3 失败,可能是由于这种丙二烯衍生物的内在不稳定性。九氟甲磺酸酯 1b 和 2 也是通过相应的甲硅烷基烯醇醚 5 和 7 与九氟丁烷磺酰氟的氟化物催化反应制备的;然而,这些两步法的总产量略低。锂化2的环碎,2-二甲基-4-亚甲基-[1,3] 二氧戊环可以以中等产率轻松制备三甲基硅氧基丙二烯 (10)。在催化量的乙酸钯 (II) 存在下,九氟甲磺酸酯 1b 和 2 与单取代烯烃顺利反应,以良好到中等的产率和高立体选择性得到预期的 Heck 偶联产物。