Meng-Meng Xu, Limin Yang, Kui Tan, Xiangyang Chen, Qi-Tao Lu, K. N. Houk, Quan Cai
{"title":"An enantioselective ambimodal cross-Diels–Alder reaction and applications in synthesis","authors":"Meng-Meng Xu, Limin Yang, Kui Tan, Xiangyang Chen, Qi-Tao Lu, K. N. Houk, Quan Cai","doi":"10.1038/s41929-021-00687-x","DOIUrl":null,"url":null,"abstract":"Compared with the conventional Diels–Alder reaction, the development of selective cross-Diels–Alder reactions between two different conjugated dienes, especially in a catalytic asymmetric manner, has been neglected. We now report a peri- and enantioselective cross-Diels–Alder reaction of 3-alkoxycarbonyl-2-pyrones with unactivated conjugated dienes catalysed by a copper(II)–bis(oxazoline) complex, leading to formal inverse-electron-demand adducts with high enantioselectivity under mild reaction conditions. Computational studies showed that this reaction proceeds through an ambimodal transition state: post-transition-state bifurcation leads to [2+4] and [4+2] adducts with the same enantioselectivity, followed by a facile Cope rearrangement to provide a single observed thermodynamic [2+4] product. This reaction occurs with a wide variety of cyclopentadienes, fulvenes and cyclohexadienes, providing a highly efficient and enantioselective approach to densely functionalized cis-bicyclic scaffolds. The synthetic value of this reaction is demonstrated by the asymmetric synthesis of two biologically important natural products, artemisinic acid and coronafacic acid. Periselective catalytic asymmetric cross-Diels–Alder reactions between two different conjugated dienes remain underdeveloped. Now, the selectivity challenges are overcome in such a reaction of electron-poor 2-pyrones and unactivated conjugated dienes, and an ambimodal transition state is identified.","PeriodicalId":18845,"journal":{"name":"Nature Catalysis","volume":null,"pages":null},"PeriodicalIF":42.8000,"publicationDate":"2021-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"6","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nature Catalysis","FirstCategoryId":"92","ListUrlMain":"https://www.nature.com/articles/s41929-021-00687-x","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 6
Abstract
Compared with the conventional Diels–Alder reaction, the development of selective cross-Diels–Alder reactions between two different conjugated dienes, especially in a catalytic asymmetric manner, has been neglected. We now report a peri- and enantioselective cross-Diels–Alder reaction of 3-alkoxycarbonyl-2-pyrones with unactivated conjugated dienes catalysed by a copper(II)–bis(oxazoline) complex, leading to formal inverse-electron-demand adducts with high enantioselectivity under mild reaction conditions. Computational studies showed that this reaction proceeds through an ambimodal transition state: post-transition-state bifurcation leads to [2+4] and [4+2] adducts with the same enantioselectivity, followed by a facile Cope rearrangement to provide a single observed thermodynamic [2+4] product. This reaction occurs with a wide variety of cyclopentadienes, fulvenes and cyclohexadienes, providing a highly efficient and enantioselective approach to densely functionalized cis-bicyclic scaffolds. The synthetic value of this reaction is demonstrated by the asymmetric synthesis of two biologically important natural products, artemisinic acid and coronafacic acid. Periselective catalytic asymmetric cross-Diels–Alder reactions between two different conjugated dienes remain underdeveloped. Now, the selectivity challenges are overcome in such a reaction of electron-poor 2-pyrones and unactivated conjugated dienes, and an ambimodal transition state is identified.
期刊介绍:
Nature Catalysis serves as a platform for researchers across chemistry and related fields, focusing on homogeneous catalysis, heterogeneous catalysis, and biocatalysts, encompassing both fundamental and applied studies. With a particular emphasis on advancing sustainable industries and processes, the journal provides comprehensive coverage of catalysis research, appealing to scientists, engineers, and researchers in academia and industry.
Maintaining the high standards of the Nature brand, Nature Catalysis boasts a dedicated team of professional editors, rigorous peer-review processes, and swift publication times, ensuring editorial independence and quality. The journal publishes work spanning heterogeneous catalysis, homogeneous catalysis, and biocatalysis, covering areas such as catalytic synthesis, mechanisms, characterization, computational studies, nanoparticle catalysis, electrocatalysis, photocatalysis, environmental catalysis, asymmetric catalysis, and various forms of organocatalysis.