Kage Mirai, Yamakoshi Hiroyuki, Tabata Manami, Ohashi Eisaku, Noguchi Kimihiro, Watanabe Takeshi, Uchida Manato, Takada Minetatsu, Ikeuchi Kazutada, Nakamura Seiichi
Graduate School of Pharmaceutical Sciences, Nagoya City University 3-1 Tanabe-dori, Mizuho-ku Nagoya 467-8603 Japan
Chem Sci. 2024 Oct 19;15(45):19070-6. doi: 10.1039/d4sc05890a.
Treatment of phthalan derivatives with -chloranil in dodecane in the presence of molecular sieves at 160-200 °C allowed the generation of unstabilized isobenzofurans, which underwent intramolecular Diels-Alder reaction to give endo cycloadducts exclusively. The cycloaddition turned out to be reversible, providing an equilibrium mixture of endo adducts when heating a substrate with a stereocenter on the tether. We also demonstrated the regioselective allylation of an oxygen-bridged cycloadduct upon exposure to EtAlCl in the presence of allyltrimethylsilane, and the conversion to Rice's intermediate completed a formal synthesis of (±)-morphine.
在160 - 200°C下，在分子筛存在的情况下，将邻苯二甲烷衍生物与四氯苯醌在十二烷中反应，可生成不稳定的异苯并呋喃，其发生分子内狄尔斯-阿尔德反应，仅生成内型环加成产物。结果表明，环加成反应是可逆的，当加热带有立体中心的底物时，会提供内型加合物的平衡混合物。我们还证明了在烯丙基三甲基硅烷存在下，将氧桥环加成产物暴露于EtAlCl时的区域选择性烯丙基化反应，转化为赖斯中间体完成了(±)-吗啡的形式合成。
