How to Suppress C(sp2)–Rh–C(sp3) Reductive Elimination and Insert CO to Achieve Rhodium-Catalyzed [5 + 2 + 1] Cycloaddition of Yne-vinylcyclopropanes and CO: Answers from Experimental and Computational Investigation
Zhiqiang Huang, Yi Jin, Sixuan Zhao, Pan Zhang, Wei Liao, Zhi-Xiang Yu
{"title":"How to Suppress C(sp2)–Rh–C(sp3) Reductive Elimination and Insert CO to Achieve Rhodium-Catalyzed [5 + 2 + 1] Cycloaddition of Yne-vinylcyclopropanes and CO: Answers from Experimental and Computational Investigation","authors":"Zhiqiang Huang, Yi Jin, Sixuan Zhao, Pan Zhang, Wei Liao, Zhi-Xiang Yu","doi":"10.1021/acscatal.4c03878","DOIUrl":null,"url":null,"abstract":"Rhodium-catalyzed [5 + 2 + 1] reaction of ene-vinylcyclopropanes (ene-VCPs) and CO is an efficient method for synthesizing eight-membered carbocycles (EMCs). However, the [5 + 2 + 1] reactions of yne-vinylcyclopropanes (yne-VCPs) are elusive. In theory, the direct reductive elimination for yne-VCPs is faster in forming C(<i>sp</i><sup>2</sup>)–C(<i>sp</i><sup>3</sup>) bonds, making the CO insertion disfavored. In this case, the [5 + 2] reaction instead of the [5 + 2 + 1] reaction would occur. In this study, we show that these hypotheses are corrected and supported by both experiments and quantum chemistry calculations. However, we found experimentally that the [5 + 2 + 1] reactions of yne-VCPs and CO can be realized for substrates with an ester or carbonyl tether and/or a substituent in their cyclopropane moiety. Further quantum chemistry calculations found that yne-VCPs with substituents in the cyclopropyl group adopt the [5 + 2 + 1] pathway, where alkyne insertion occurs ahead of CO insertion. The introduced substituents help the CO insertion and its followed reductive elimination, which consequently makes the [5 + 2 + 1] reaction dominate. However, yne-VCPs with an ester or carbonyl tether adopt a [5 + 1 + 2] pathway where CO insertion happens before alkyne insertion. The reason for this switch is that the carbonyl group in the tether coordinates with the Rh atom of the catalyst and assists CO insertion, which makes the generation of EMCs possible.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":11.3000,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acscatal.4c03878","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: 0
Abstract
Rhodium-catalyzed [5 + 2 + 1] reaction of ene-vinylcyclopropanes (ene-VCPs) and CO is an efficient method for synthesizing eight-membered carbocycles (EMCs). However, the [5 + 2 + 1] reactions of yne-vinylcyclopropanes (yne-VCPs) are elusive. In theory, the direct reductive elimination for yne-VCPs is faster in forming C(sp2)–C(sp3) bonds, making the CO insertion disfavored. In this case, the [5 + 2] reaction instead of the [5 + 2 + 1] reaction would occur. In this study, we show that these hypotheses are corrected and supported by both experiments and quantum chemistry calculations. However, we found experimentally that the [5 + 2 + 1] reactions of yne-VCPs and CO can be realized for substrates with an ester or carbonyl tether and/or a substituent in their cyclopropane moiety. Further quantum chemistry calculations found that yne-VCPs with substituents in the cyclopropyl group adopt the [5 + 2 + 1] pathway, where alkyne insertion occurs ahead of CO insertion. The introduced substituents help the CO insertion and its followed reductive elimination, which consequently makes the [5 + 2 + 1] reaction dominate. However, yne-VCPs with an ester or carbonyl tether adopt a [5 + 1 + 2] pathway where CO insertion happens before alkyne insertion. The reason for this switch is that the carbonyl group in the tether coordinates with the Rh atom of the catalyst and assists CO insertion, which makes the generation of EMCs possible.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.