{"title":"Gold(i)-catalysed cyclisation of (E)-ketene-N,O-acetals: a synthetic route toward spiro-oxazole-γ-lactones†‡","authors":"Suresh Kanikarapu , Rangu Prasad , Manoj Sethi , Akhila K. Sahoo","doi":"10.1039/d4ob00551a","DOIUrl":null,"url":null,"abstract":"<div><p>In this study, we developed a cascade 5,5-cyclisation of internal ketene-<em>N</em>,<em>O</em>-acetals utilizing homogeneous Au(<span>i</span>) catalysis. This process involves an initial 5-<em>exo-dig</em> carbocyclisation, followed by a 5-<em>exo-dig</em> heterocyclisation that stereoselectively incorporates the O-atom of a water molecule into an N-tethered propargyl alkyne. This sequential reaction results in the formation of one C–C, two C–O, and two C–I bonds, ultimately leading to the synthesis of spiro-α-iodo-γ-lactone structures featuring oxazole rings in good yields.</p></div>","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organic & Biomolecular Chemistry","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/org/science/article/pii/S1477052024004683","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 developed a cascade 5,5-cyclisation of internal ketene-N,O-acetals utilizing homogeneous Au(i) catalysis. This process involves an initial 5-exo-dig carbocyclisation, followed by a 5-exo-dig heterocyclisation that stereoselectively incorporates the O-atom of a water molecule into an N-tethered propargyl alkyne. This sequential reaction results in the formation of one C–C, two C–O, and two C–I bonds, ultimately leading to the synthesis of spiro-α-iodo-γ-lactone structures featuring oxazole rings in good yields.