{"title":"Ni-Catalyzed ZnCl2–Assisted Domino Coupling of Enones and Alkyne-Tethered Vinylcyclopropanes via C–C Bond Cleavage of Cyclopropane","authors":"Mika Sakazaki, and , Shin-ichi Ikeda*, ","doi":"10.1021/acs.organomet.4c0034110.1021/acs.organomet.4c00341","DOIUrl":null,"url":null,"abstract":"<p >A Ni-catalyzed, ZnCl<sub>2</sub>-assisted domino coupling of enones and alkyne-tethered vinylcyclopropanes (VCPs) was developed. The reaction proceeds through the following steps: (1) oxidative cyclization of a Ni(0) complex with an enone and the alkyne component of the alkyne-tethered VCP in the presence of ZnCl<sub>2</sub>, (2) carbonickelation of the VCP moiety, (3) β-C elimination leading to C–C bond cleavage of the cyclopropane moiety, and (4) β-H elimination to stereoselectively obtain (<i>E</i>)-1,3-diene as the coupling product. The optimal reaction conditions and scope of enones and alkyne-tethered VCPs were systematically explored. The reaction mechanism was investigated by performing deuterium-labeling experiments and density functional theory (DFT) calculations on the model compounds. The results clarify that the β-C elimination process occurs readily, and the Ni(0) precatalyst is regenerated via the 1,4-addition of H–Ni(II) species, generated by β-H elimination, to an excess of enone, followed by Zn reduction of the formed 1,4-adduct.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organometallics","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.organomet.4c00341","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
A Ni-catalyzed, ZnCl2-assisted domino coupling of enones and alkyne-tethered vinylcyclopropanes (VCPs) was developed. The reaction proceeds through the following steps: (1) oxidative cyclization of a Ni(0) complex with an enone and the alkyne component of the alkyne-tethered VCP in the presence of ZnCl2, (2) carbonickelation of the VCP moiety, (3) β-C elimination leading to C–C bond cleavage of the cyclopropane moiety, and (4) β-H elimination to stereoselectively obtain (E)-1,3-diene as the coupling product. The optimal reaction conditions and scope of enones and alkyne-tethered VCPs were systematically explored. The reaction mechanism was investigated by performing deuterium-labeling experiments and density functional theory (DFT) calculations on the model compounds. The results clarify that the β-C elimination process occurs readily, and the Ni(0) precatalyst is regenerated via the 1,4-addition of H–Ni(II) species, generated by β-H elimination, to an excess of enone, followed by Zn reduction of the formed 1,4-adduct.
期刊介绍:
Organometallics is the flagship journal of organometallic chemistry and records progress in one of the most active fields of science, bridging organic and inorganic chemistry. The journal publishes Articles, Communications, Reviews, and Tutorials (instructional overviews) that depict research on the synthesis, structure, bonding, chemical reactivity, and reaction mechanisms for a variety of applications, including catalyst design and catalytic processes; main-group, transition-metal, and lanthanide and actinide metal chemistry; synthetic aspects of polymer science and materials science; and bioorganometallic chemistry.