Download PDF
Synlett 2006(18): 3167-3169  
DOI: 10.1055/s-2006-944215
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Convenient Protocol for the Synthesis of Hindered Aryl Malononitriles

Anita Schnyder*a, Adriano F. Indoleseb, Thomas Maetzkec, Jean Wengerd, Hans-Ulrich Blasera
a Solvias AG, Postfach, 4002 Basel, Switzerland
Fax: +41(61)6866311; e-Mail: anita.schnyder@solvias.com;
b Novasep AG, Gempenstr. 6, 4133 Pratteln, Switzerland
c Polyphor AG, Gewerbestr. 14, 4123 Allschwil, Switzerland
d Syngenta AG, Postfach, 4002 Basel, Switzerland
Further Information

Publication History

Received 8 March 2006
Publication Date:
04 August 2006 (online)

    Permissions and Reprints All articles of this category

Abstract

A technically feasible method has been developed for the synthesis of variety of aryl malononitriles in high yields (70-95%) using the palladium-catalyzed coupling reaction of malononitrile with aryl bromides and chlorides, respectively. The influence a ­several reaction parameters such as base, ligand, solvent or tem­perature were investigated in some detail.

Key words

arylation - aryl malononitrile - C-C coupling reaction - Pd catalysis - oxopyrazoline herbicide

    References and Notes

  • 1a Cederbaum F, Brunner HG, and Boeger M. inventors; WO  9216510 A1.  ; Chem. Abstr. 1993, 118, 38935
  • 1b Krueger BW, Fischer R, Bertram HJ, Bretschneider T, Boehm S, Krebs A, Schenke T, Santel HJ, and Luerssen K. inventors; DE  4109208.  ; Chem. Abstr. 1993, 118, 22227
  • 1c Muehlebach M, Glock J, Maetzke T, and Stoller A. inventors; WO  9947525 A1.  ; Chem. Abstr. 1999, 131, 228720
  • 1d Muehlebach M, Glock J, Maetzke T, and Stoller A. inventors; WO  2000047585A1.  ; Chem. Abstr. 2000, 133, 164053
  • 1e Maetzke T, Mutti R, and Szczepanski H. inventors; WO  2000078881 A2.  ; Chem. Abstr. 2000, 134, 56699
  • 2 Cristau H.-J. Cellier PP. Spindler J.-F. Taillefer M. Chem. Eur. J.  2004,  10:  5607 ; and references therein
    CrossrefPubMedGoogle Scholar
  • 3 Cristau H.-J. Vogel R. Taillefer M. Gadras A. Tetrahedron Lett.  2000,  41:  8457 
    CrossrefGoogle Scholar
  • 4 Uno M. Seto K. Takahashi S. J. Chem. Soc., Chem. Commun.  1984,  932 
    CrossrefGoogle Scholar
  • 6 Gao C. Tao X. Qian Y. Huang J. Synlett  2003,  1716 
    Article in Thieme ConnectGoogle Scholar
  • 7 Gao C. Tao X. Qian Y. Huang J. Chem. Commun.  2003,  1414 
    CrossrefGoogle Scholar
  • 8a Beare NA. Hartwig JF. J. Org. Chem.  2002,  67:  541 
    CrossrefGoogle Scholar
  • 8b Fox JM. Huang X. Chieffi A. Buchwald SL. J. Am. Chem. Soc.  2000,  122:  1360 
    CrossrefGoogle Scholar
  • 10 Zapf A. Beller M. Chem. Eur. J.  2000,  6:  1830 
    Google Scholar
  • 11 Schnyder A. Aemmer T. Indolese AF. Pittelkow U. Studer M. Adv. Synth. Catal.  2002,  344:  495 
    CrossrefGoogle Scholar
5

This method indeed worked well in our hands for the preparation of 2 using substrate 1b (58% yield), but failed completely when the technically more suitable bromide 1a was used.

9

Standard Experiment.
Malononitrile (181 mg, 2.75 mmol), t-BuONa (720 mg, 7.5 mmol) and xylene (13 mL) were stirred in a Schlenk tube under argon at r.t. for 1 h. Aryl halide (2.5 mmol) and a mixture of PdCl2 (2.5 µmol) and PCy3 (17.5 µmol) in xylene (2 mL) were added and the reaction mixture was stirred at the required temperature. For the experiments described in Table [2] , the product was extracted with NaOH solution and after acidification with HCl, was isolated by filtration. The 1H NMR spectra of all products were in agreement with the proposed structures.