{"title":"Oxidative generation of isobenzofurans from phthalans: application to the formal synthesis of (±)-morphine","authors":"Mirai Kage, Hiroyuki Yamakoshi, Manami Tabata, Eisaku Ohashi, Kimihiro Noguchi, Takeshi Watanabe, Manato Uchida, Minetatsu Takada, Kazutada Ikeuchi, Seiichi Nakamura","doi":"10.1039/d4sc05890a","DOIUrl":null,"url":null,"abstract":"Treatment of phthalan derivatives with <em>p</em>-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 having a stereocenter on the tether. We also demonstrated the regioselective allylation of an oxygen-bridged cycloadduct upon exposure to EtAlCl<small><sub>2</sub></small> in the presence of allyltrimethylsilane, and the conversion to Rice’s intermediate completed a formal synthesis of (±)-morphine.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":null,"pages":null},"PeriodicalIF":7.6000,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Science","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4sc05890a","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Treatment of phthalan derivatives with p-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 having a stereocenter on the tether. We also demonstrated the regioselective allylation of an oxygen-bridged cycloadduct upon exposure to EtAlCl2 in the presence of allyltrimethylsilane, and the conversion to Rice’s intermediate completed a formal synthesis of (±)-morphine.
期刊介绍：
Chemical Science is a journal that encompasses various disciplines within the chemical sciences. Its scope includes publishing ground-breaking research with significant implications for its respective field, as well as appealing to a wider audience in related areas. To be considered for publication, articles must showcase innovative and original advances in their field of study and be presented in a manner that is understandable to scientists from diverse backgrounds. However, the journal generally does not publish highly specialized research.
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