Copper-Mediated Fluoroalkylation Reactions with [(Phenylsulfonyl)-difluoromethyl]trimethylsilane: Synthesis of PhSO₂CF₂-Containing Allenes and Alkynes

Abstract

Copper-mediated (phenylsulfonyl)difluoromethylation of propargyl chlorides and alkynyl halides with PhSO₂CF₂TMS reagent was successfully achieved to give PhSO₂CF₂-containing allenes and alkynes, respectively. It is believed that the in situ formed PhSO₂CF₂Cu species is involved in the present (phenylsulfonyl)difluoromethylation reactions.

Key words

fluoroalkylation - copper - allenes - alkynes - (phenylsulfonyl)difluoromethyl

References and Notes

• 1a Organofluorine Compounds: Chemistry and Applications   Hiyama T. Springer; New York: 2000. 
• 1b Fluorine in Medicinal Chemistry and Chemical Biology   Ojima I. Wiley; West Sussex: 2009. 
• 1c Organofluorine Chemistry: Principles and Commercial Applications   Banks RE. Smart BE. Tatlow JC. Plenum Press; New York: 1994. 
• 2a Uneyama K. Organofluorine Chemistry   Blackwell; New Delhi: 2006. 
• 2b Chambers RD. Fluorine in Organic Chemistry   Blackwell; Oxford: 2004. 
• 2c Kirsch P. Modern Fluoroorganic Chemistry: Synthesis, Reactivity, Applications   Wiley-VCH; Weinheim: 2004. 
• 3a Hu J. J. Fluorine Chem.  2009,  130:  1130 
• 3b Prakash GKS. Hu J. Acc. Chem. Res.  2007,  40:  921 
• 3c Hu J. Zhang W. Wang F. Chem. Commun.  2009,  7465 
• 4a Mcloughlin VCR. Thrower J. Tetrahedron  1969,  25:  5921 
• 4b Kobayashi Y. Kumadaki I. Tetrahedron Lett.  1969,  10:  4095 
• 4c Kondratenko NV. Vechirko EP. Yagupolskii LM. Synthesis  1980,  932 
• 4d Wiemers DM. Burton DJ. J. Am. Chem. Soc.  1986,  108:  832 
• 4e Carr GE. Chambers RD. Holms TF. Parker DG. J. Chem. Soc., Perkin Trans. 1  1988,  921 
• 4f Chen Q.-Y. Wu S.-W. J. Chem. Soc., Chem. Commun.  1989,  705 
• 4g Willert-Porada MA. Burton DJ. Baenziger NC. J. Chem. Soc., Chem. Commun.  1989,  1633 
• 4h Urata H. Fuchikami T. Tetrahedron Lett.  1991,  32:  91 
• 4i Cottet F. Schlosser M. Eur. J. Org. Chem.  2002,  327 
• 4j Dubinina GG. Furutachi H. Vivic DA. J. Am. Chem. Soc.  2008,  130:  8600 
• 5 Oishi M. Kondo H. Amii H. Chem. Commun.  2009,  1909 
• Recently, palladium-mediated trifluoromethylations of aryl halides were reported:
• 6a Cho EJ. Senecal TD. Kinzel T. Zhang Y. Watson DA. Buchwald SL. Science  2010,  328:  1679 
• 6b Wang X. Truesdale L. Yu J.-Q. J. Am. Chem. Soc.  2010,  132:  3648 
• 6c Ball ND. Kampf JW. Sanford MS. J. Am. Chem. Soc.  2010,  132:  2878 
• 6d Grushin VV. Marshall WJ. J. Am. Chem. Soc.  2006,  128:  12644 
• 6e Grushin VV. Marshall WJ. J. Am. Chem. Soc.  2006,  128:  4632 
• 8 More recently, Leito and co-workers reported that CF₃Cu derived from TMSCF₃/KF/CuBr/DMF/DMI system contains three species: CF₃Cu˙KBr (76%, ^¹9F NMR: δ = -28.8 ppm), [(CF₃)₂Cu]^- Κ⁺ (21%, ^¹9F NMR: δ = -32.4 ppm), and [(CF₃)₄Cu]^-Κ⁺ (3%, ^¹9F NMR: δ = -35.7 ppm). See: Kütt A. Movchum V. Rodima T. Dansauer T. Rusanov EB. Leito I. Kaljurand I. Koppel J. Pihl V. Koppel I. Ovsjannikov G. Toom L. Mishima M. Medebielle M. Lork E. Röschenthaler G.-V. Koppel IA. Kolomeitsev AA. J. Org. Chem.  2008,  73:  2607 
• 9a Li Y. Liu J. Zhang L. Zhu L. Hu J. J. Org. Chem.  2007,  72:  5824 
• 9b Li Y. Li H. Hu J. Tetrahedron  2009,  65:  478 
• 9c Prakash GKS. Hu J. Wang Y. Olah GA. Org. Lett.  2004,  6:  4315 
• 10a Taguchi T. Kitagawa O. Morikawa T. Nishiwaki T. Uehara H. Endo H. Kobayashi Y. Tetrahedron Lett.  1986,  27:  6103 
• 10b Sato K. Omote M. Ando A. Kumadaki I. J. Fluorine Chem.  2004,  125:  509 
• 11a Yokomatsu T. Suemune K. Murano T. Shibuya S.
  J. Org. Chem.  1996,  61:  7207 
• 11b Yokomatsu T. Murano T. Suemune K. Shibuya S. Tetrahedron  1997,  53:  815 
• 12a Ni C. Hu J. Tetrahedron Lett.  2005,  46:  8273 
• 12b Liu J. Ni C. Wang F. Hu J. Tetrahedron Lett.  2008,  49:  1605 
• 12c Zhang W. Zhu J. Hu J. Tetrahedron Lett.  2008,  49:  5006 
• 12d Zhang W. Huang W. Hu J. Angew. Chem. Int. Ed.  2009,  48:  9858 
• 13 The CF₂HCu species [^¹9F NMR: δ = -114.6 (d), -116.2 (d) ppm] was also previously reported. See: Burton DJ. Hartgraves GA. J. Fluorine Chem.  2007,  128:  1198 
• 15 The decomposition of PhSO₂CF₂ ^- into difluorocarbene and benzenesulfinate was previously known. See: Hine J. Porter JJ. J. Am. Chem. Soc.  1960,  82:  6178 ; however, we observed that when species 2 was kept at 0 ˚C or lower temperature, the decomposition was significantly slower
• Known examples of fluoroalkylation of propargyl halides:
• 16a Burton DJ. Hartgraves GA. Hsu J. Tetrahedron Lett.  1990,  31:  3699 
• 16b

  See also ref. 13.

• 17 Zhao Y. Zhu J. Ni C. Hu J. Synthesis  2010,  1899 
• 18a Sargent M. Dean FM. In Comprehensive Heterocyclic Chemistry   Vol. 3:  Pergamon Press; Oxford: 1984. 
• 18b Nakanishi K. Goto T. Ito S. Natori S. Nozoe S. In Natural Products Chemistry   Kodansha; Tokyo: 1974. 
• 18c Lipshutz BH. Chem. Rev.  1986,  86:  795 
• 19 Li P. Chai Z. Zhao G. Zhu S. Synlett  2008,  2547 
• 20 For a recent example of using CuCl₂ as an oxidative chlorinating reagent, see: Kalyani D. Satterfield AD. Sanford MS. J. Am. Chem. Soc.  2010,  132:  8419 

7

In many cases, the structure of CF₃Cu species was not well defined. Based on their NMR study, Burton and co-workers have shown that CF₃Cu has three forms in their reaction system, all of which could serve as trifluoromethylating agents, see ref. 4d.

14

Similar to CF₃Cu and CF₂HCu, PhSO₂CF₂Cu is likely
to have more than one form in solution (such as PhSO₂CF₂Cu˙L and [(PhSO₂CF₂)₂Cu]^-Cs⁺ ), so there was more than one signal in its ^¹9F NMR spectrum; see ref. 7, 8, and 13.