A Short, Convenient Synthesis of Cyclopentenones via Derivatives of exo-Dicyclopentadiene

References

• Ellison , R. A. 1973 . Synthesis , : 397 Review: For syntheses of 2-cyclopentenones (1), as applied to prostaglandins, see G. Stork, S. Raucher, J. Am. Chem. Soc., 98, 1583(1976), and E. J. Corey, G. Moinet, J. Am. Chem. Soc., 95, 6831(1973). See also R. E. Ireland, R. H. Mueller, J. Am. Chem. Soc., 94, 5897(1972)
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• Stork , G. , Nelson , G. L. , Rouessac , F. and Gringore , O. 1971 . J. Am. Chem. Soc. , 93 : 3091
   Web of Science ®Google Scholar
• Wiel , J.-B and Rouessac , F. 1976 . Chem. Commun. , : 446 See also J. L. Ripoll, A. Rouessac, F. Rouessac, Tetrahedron, 34, 19(1978)
   Google Scholar
• Khand , I. U. , Knox , G. R. , Pauson , P. L. , Watts , W. E. and Foreman , M. I. 1973 . J. Chem. Soc. Perkin I , : 977
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• Norbornadiene was freshly distilled from LiAlH4 and stored under N2, thereby minimizing the interference of peroxide-induced exothermic radical reactions
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• In contrast to the published4 report, this reaction apparently does not yield the exo-fused ketone stereospecifically from substituted acetylenes; we have obtained up to 2% yield of endo-ketone as well
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• Posner , G. H. 1972 . Org. React. , 19 : 1
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• Corey , E. J. and Beames , D. J. 1972 . J. Am. Chem. Soc. , 94 : 7210
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• Quenching after 2 hrs at -78° (no warming) affords only unreacted starting material
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• Sternhell , S. 1969 . Quart. Rev. , 23 : 236
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• The nmr of the crude product also exhibits a doublet, J = 7 Hz, located at δ 0.70 ppm, which may be due to the cis isomer12 of 8e. This component makes up less than 2% of the product mixture
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• Bautick , J. R. and Rothstein , E. 1971 . J. Chem. Soc., (C) , : 2515 Phenyl groups strongly shield cis-vicinal alkyl groups in cyclopentenones. See
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