Stefano Barranco, Alessio Pagnanini, Federico Cuccu, Pierluigi Caboni, Régis Guillot, David J. Aitken, Angelo Frongia
{"title":"Substrate-dependent regiodivergence in [3 + 2] annulation reactions of 2-(phenacylethylidene)cyclobutanones with thioureas","authors":"Stefano Barranco, Alessio Pagnanini, Federico Cuccu, Pierluigi Caboni, Régis Guillot, David J. Aitken, Angelo Frongia","doi":"10.1039/d4ob01103a","DOIUrl":null,"url":null,"abstract":"The [3 + 2] annulation reaction between a thiourea, an ambident dinucleophile, and a 2-(phenacylethylidene)cyclobutanone, containing a novel pull–pull alkene system, could in principle proceed with several chemo- and regioselectivity profiles. Here we describe a convenient synthesis of the functionalized cyclobutanone substrates and show that they react with thioureas in a manner that is rationalized mechanistically in terms of the steric and electronic effects at play. The [3 + 2] annulation proceeds in mild, additive-free conditions to provide access to previously unknown cyclobutane-fused imidazolidine-2-thione and thiazolidine-2-imine derivatives in good yields.","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-09-06","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/d4ob01103a","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
The [3 + 2] annulation reaction between a thiourea, an ambident dinucleophile, and a 2-(phenacylethylidene)cyclobutanone, containing a novel pull–pull alkene system, could in principle proceed with several chemo- and regioselectivity profiles. Here we describe a convenient synthesis of the functionalized cyclobutanone substrates and show that they react with thioureas in a manner that is rationalized mechanistically in terms of the steric and electronic effects at play. The [3 + 2] annulation proceeds in mild, additive-free conditions to provide access to previously unknown cyclobutane-fused imidazolidine-2-thione and thiazolidine-2-imine derivatives in good yields.