Synthesis of a biofuel target through conventional organic chemistry

TETRAHEDRON LETTERS

卷:59

Article

Page, Jordan P.¹  Robinson, Joshua W.¹  Albrecht, Karl O.¹  Cosimbescu, Lelia¹ 

[1] Pacific Northwest Natl Lab, Energy & Environm Directorate, 902 Battelle Blvd, Richland, WA 99354 USA

关键词: Biofuels;    Cyclopentadiene;    Alkenes;    Grignard cross-coupling;    Divergent synthesis;   

DOI  :  10.1016/j.tetlet.2018.02.073

来源: Elsevier

【 摘 要 】

In this work, the biofuel target compound 2-ethyl-5,5-dimethylcyclopenta-1,3-diene (1) and its exo isomers (9a and 9b), were successfully synthesized via two different pathways from the common intermediate 4,4-dimethylcyclopent-2-ene-l-one (2). The first pathway produced the endocyclic product as a pure isomer via a triflate intermediate obtained from ketone 2 in 60% yield, followed by copper-catalyzed coupling with ethyl magnesium bromide in 63% yield. The second pathway employed a Grignard reaction with ketone 2, which generated an alcohol that was immediately subjected to mild acid-catalyzed elimination to yield primarily a mixture of exo isomers 9a and 9b in 46% yield. The preparation method developed by this work allowed for the production of a sufficient quantity of these targets to evaluate their fuel properties, which will be reported in a separate study. (C) 2018 Elsevier Ltd. All rights reserved.

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