Synlett 2005(15): 2379-2381  
DOI: 10.1055/s-2005-872261
LETTER
© Georg Thieme Verlag Stuttgart · New York

Towards the Synthesis of Paulitin: New Insights into the Enyne-Metathesis Mechanism

Emeline Vedrenne, Frédérique Royer, Julie Oble, Laurent El Kaïm, Laurence Grimaud*
Laboratoire Chimie et Procédés, Ecole Nationale Supérieure de Techniques Avancées, 32 Bd Victor, 75739 Paris Cedex 15, France
Fax: +33(1)45528322; e-Mail: laurence.grimaud@ensta.fr;
Weitere Informationen

Publikationsverlauf

Received 9 June 2005
Publikationsdatum:
03. August 2005 (online)

Abstract

In our approach towards Paulitin, a sesquiterpene lactone, we have shown that steric hindrance at the propargylic position is of importance to the outcome of enyne metathesis. Moreover, we have uncovered further evidence to confirm that the alkyne-first pathway should be the favored process in enyne metathesis.

    References

  • 1a David JP. Santos AJ. Guedes ML. David JM. Chai H.-B. Pezzuto JM. Angerhofer CK. Cordell GA. Pharm. Biol.  1999,  37:  165 
  • 1b This molecule had been previously isolated from Ambrosia dumosa in 1979, see: Seaman FC. Mabry TJ. Rev. Latinoam. Quim.  1979,  10:  85 
  • 2 Likhitwitayawuld K. Angerhofer CK. Cordell GA. Pezzuto JM. Ruangrungsi N. J. Nat. Prod.  1993,  56:  30 
  • 3a Kingsbury JS. Harrity JPA. Bonitatebus PJ. Hoveyda AH. J. Am. Chem. Soc.  1999,  121:  791 
  • 3b Garber SB. Kingsbury JS. Gray BL. Hoveyda AH. J. Am. Chem. Soc.  2000,  122:  8168 
  • 3c Gessler S. Randl S. Blechert S. Tetrahedron Lett.  2000,  41:  9973 
  • For recent reviews on enyne metathesis, see:
  • 4a Diver ST. Giessert AJ. Chem. Rev.  2004,  104:  1317 
  • 4b Poulsen CS. Madsen R. Synthesis  2003,  1 
  • For a discussion concerning enyne metathesis mechanism, see:
  • 5a Kinoshita A. Mori M. Synlett  1994,  1020 
  • 5b Stragies R. Schuster M. Blechert S. Angew. Chem., Int. Ed. Engl.  1997,  36:  2518 
  • 5c For a more recent study, see: Galan BR. Giessert AJ. Keister JB. Diver ST. J. Am. Chem. Soc.  2005,  127:  5762 
  • 6 Recently, in contrast to our results, Diver and co-workers suggested that more substituted alkynes gave faster reactions: Galan BR. Giessert AJ. Keister JB. Diver ST. J. Am. Chem. Soc.  2005,  127:  5762 
  • 8a

    This could be done in a one-step procedure according to our previous work (see ref. 8b) or in a two-step procedure (see ref. 8c).

  • 8b Royer F. Vilain C. El Kaïm L. Grimaud L. Org. Lett.  2003,  5:  2007 
  • 8c Cesati RR. De Armas J. Hoveyda AH. J. Am. Chem. Soc.  2004,  126:  96 
  • 9a Choi T.-L. Grubbs RH. Chem. Commun.  2001,  2648 
  • 9b Boyer F.-D. Hanna I. Ricard L. Org. Lett.  2004,  6:  1817 
7

According to NMR spectra, regioisomer 2 seemed to be isolated as one single stereoisomer whose configuration was not determined.