Synthesis 2012(6): 857-861  
DOI: 10.1055/s-0031-1290157
© Georg Thieme Verlag Stuttgart ˙ New York

Facile Synthesis of Substituted 1,1-Difluoroallenes via Carbonyl Difluorovinylidenation

Ken Oh, Kohei Fuchibe, Misaki Yokota, Junji Ichikawa*
Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
Fax: 81(29)8534237; e-Mail: [email protected];
Further Information

Publication History

Received 22 November 2011
Publication Date:
16 January 2012 (online)


Two methods for the difluorovinylidenation of carbonyl compounds have been developed to synthesize 1,1-difluoroallenes bearing various substituents. The reaction of 1-bromo-2,2-difluorovinyllithium, generated from 1,1-dibromo-2,2-difluoroethylene and n-butyllithium, with aldehydes or ketones, and subsequent acetylation, gives 2-bromo-3,3-difluoroallylic acetates. Elimination of these acetates with n-butyllithium affords 1,1-difluoroallenes in high yield. 3,3-Difluoro-2-iodoallylic acetates are similarly prepared from aldehydes or ketones on treatment with 2,2-difluoro-1-iodovinyllithium, generated from 1,1,1-trifluoro-2-iodoethane and lithium diisopropylamide, followed by acetylation. These acetates readily undergo elimination with zinc metal to afford 1,1-difluoroallenes in high yield.


  • 1 Krause N. Hoffmann-Röder A. In Modern Allene Chemistry   Krause N. Hashmi ASK. Wiley-VCH; Weinheim: 2004.  p.997 
  • 2 For the synthesis of non-fluorinated allenes, see: Brummond M. DeForrest JE. Synthesis  2007,  795 
  • For the synthesis of fluorinated allenes, see:
  • 3a Dolbier WR. Burkholder CR. Piedrahita CA. J. Fluorine Chem.  1982,  20:  637 
  • 3b Shi G. Xu Y. J. Fluorine Chem.  1989,  44:  161 
  • 3c Wang Z. Hammond GB. J. Org. Chem.  2000,  65:  6547 
  • 3d Mae M. Hong JA. Xu B. Hammond GB. Org. Lett.  2006,  8:  479 
  • See also:
  • 4a Zens AP. Ellis PD. Ditchfield R. J. Am. Chem. Soc.  1974,  96:  1309 
  • 4b Castelhano AL. Krantz A. J. Am. Chem. Soc.  1987,  109:  3491 
  • 4c Lu H. Friedrich HB. Burton DJ. J. Fluorine Chem.  1995,  75:  83 
  • 4d Xu B. Hammond GB. Angew. Chem. Int. Ed.  2008,  47:  689 
  • 5a Yokota M. Fujita D. Ichikawa J. Org. Lett.  2007,  9:  4639 
  • 5b Oh K. Fuchibe K. Ichikawa J. Synthesis  2011,  881 
  • 6 Anilkumar R. Burton DJ. J. Fluorine Chem.  2005,  126:  455