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William J. Kerr,* Mark McLaughlin, Angus J. Morrison, and Peter L. Pauson

Formal Total Synthesis of (+/-)- α - and β - Cedrene by Preparation of Cedrone . Construction of the Tricyclic Carbon Skeleton by the Use of a Highly Efficient Intramolecular Khand Annulation. William J. Kerr,* Mark McLaughlin, Angus J. Morrison, and Peter L. Pauson. William J. Kerr.

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William J. Kerr,* Mark McLaughlin, Angus J. Morrison, and Peter L. Pauson

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  1. Formal Total Synthesis of (+/-)-α- and β-Cedrene by Preparation of Cedrone. Construction of the Tricyclic Carbon Skeleton by the Use of a Highly Efficient IntramolecularKhandAnnulation William J. Kerr,* Mark McLaughlin, Angus J. Morrison, and Peter L. Pauson

  2. William J. Kerr • University of Strathclyde– Glasgow U.K. • B.S. 1983 University of Strathclyde • Ph.D. 1986 University of Strathclyde • Peter Pauson and David Billington • NIH Postdoc– Brandeis University - MA • Myron Rosenblum • Postdoc – Imperial College – London • Steven Ley • 1989 – University of Strathclyde • 1991 – ICI Fine Chemicals Young Lecturer • 1997 Glaxo Welcome Prize for Innovative Organic Chem • 2002 Chair of Organic Chemistry – University of Strathclyde • Interests: Metal Mediated Synthetic Organic Chemistry

  3. α- and β-Cedrene • Isolated in 1841 • Walter, P. Ann. Chem. 1841, 39, 247 • Juniperuscedrusand Juniperusthurifera • Characterized in 1953 • Stork, G.; Breslow, R. J. Am. Chem. Soc. 1953, 75, 3291

  4. Retrosynthesis • Key Step: IntramolecularPausonKhand • PausonKhand cyclization has been used in synthesis of other natural products. • Pentalenene, Hirsutene, Brefeldin A…etc

  5. Forward SynthesisScheme 1 • 2nd Step: Originally - Saegusa Oxidation • Worked 92% yield • Not Catalytic – Used diallyl carbonate stoichiometric

  6. Scheme 2 • Seyferth-Gilbert Homologation – Ohira-Bestmann reagent

  7. Scheme 3Pauson-Khand Cyclization

  8. Scheme 4 • Mech of ketone deprotection

  9. Final StepsScheme 5.

  10. Conclusion • Able to utilize the PausonKhand cyclization • Formation of intermediate • Synthesis of target from simple starting material • Questions??

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