{"title":"Investigating chemical diversity: <i>o</i>-propargylphenols as key compounds in the divergent synthesis of 2-substituted benzofurans and chromenes.","authors":"Alessandra Gritti, Elisa Brambilla, Ilaria Nania, Federico Turba, Valentina Pirovano, Giorgio Abbiati","doi":"10.1039/d4ob01272k","DOIUrl":null,"url":null,"abstract":"<p><p>In this study, we explored and optimized a MW-enhanced divergent approach for the synthesis of 2-substituted benzofurans and chromenes, starting from seventeen substituted <i>o</i>-propargylphenols characterized by a monoaryl substitution on the propargylic sp<sup>3</sup> carbon. Firstly, we developed a robust platform for the preparation of a library of <i>o</i>-propargylphenols. Under basic conditions, <i>o</i>-propargylphenols reacted regioselectively to yield benzofurans in yields ranging from 43% to 100%. Conversely, under cationic gold catalysis, we were able to obtain the corresponding 4<i>H</i>-chromenes, albeit in more variable yields (from 25% to 93%) and slightly lower regioselectively. We also proposed plausible mechanisms to explain the divergent outcomes observed. Our findings underscore the potential of diversity-oriented synthesis in the investigation of molecular complexity. Our neglected <i>o</i>-propargylphenols have proven to be versatile and strategic starting materials for accessing oxygen-containing heterocyclic scaffolds through intramolecular cyclization reactions.</p>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organic & Biomolecular Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4ob01272k","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, ORGANIC","Score":null,"Total":0}
引用次数: 0
Abstract
In this study, we explored and optimized a MW-enhanced divergent approach for the synthesis of 2-substituted benzofurans and chromenes, starting from seventeen substituted o-propargylphenols characterized by a monoaryl substitution on the propargylic sp3 carbon. Firstly, we developed a robust platform for the preparation of a library of o-propargylphenols. Under basic conditions, o-propargylphenols reacted regioselectively to yield benzofurans in yields ranging from 43% to 100%. Conversely, under cationic gold catalysis, we were able to obtain the corresponding 4H-chromenes, albeit in more variable yields (from 25% to 93%) and slightly lower regioselectively. We also proposed plausible mechanisms to explain the divergent outcomes observed. Our findings underscore the potential of diversity-oriented synthesis in the investigation of molecular complexity. Our neglected o-propargylphenols have proven to be versatile and strategic starting materials for accessing oxygen-containing heterocyclic scaffolds through intramolecular cyclization reactions.