1-Bromo-2-ethoxycyclopropyllithium: A Synthetic Equivalent of 2-Lithio-or 3-Lithiopropenal. Application to the Synthesis of Juvenile Hormone (JH-II), β-Sinensal, and Jasmonoids
作者:Yoshitomi Morizawa、Akihiro Kanakura、Hajime Yamamoto、Tamejiro Hiyama、Hitosi Nozaki
DOI:10.1246/bcsj.57.1935
日期:1984.7
resulting lithium carbenoid 3 was allowed to react with various electrophiles to give 1-substituted trans-1-bromo-2-ethoxycyclopropanes (1) in good yields. The trans relationship of Br and OEt groups was found particularly pertinent to the ethanolysis of 1 producing 2-substituted propenal diethyl acetal derivatives. The reaction has been applied to 1-methoxycyclohexene–dibromocarbene adducts, giving
乙基乙烯基醚-二溴卡宾加合物在四氢呋喃中在 -95 °C 下用丁基锂锂化。使所得卡宾酸锂 3 与各种亲电子试剂反应,以良好的产率得到 1-取代的反式-1-溴-2-乙氧基环丙烷 (1)。发现 Br 和 OEt 基团的反式关系与 1 的乙醇分解作用特别相关,产生 2-取代的丙烯醛二乙缩醛衍生物。该反应已应用于 1-甲氧基环己烯-二溴卡宾加合物,从而在环扩大下产生 2-取代的 2-环庚烯-1-一二甲基缩醛。通过分别用二甲基铜酸锂 (I) 或五羰基铁 SN2' 取代烯丙基乙酸酯,该转化已用于合成类萜 (JH-II) 或萜类 (β-sinensal) 结构。