AgI-PEG400-KI Catalyzed Environmentally Benign Synthesis of Aroyl Cyanides Using Potassium Hexacyanoferrate(II) as the Cyanating Agent

Abstract

A practical cyanation of aroyl chlorides with 0.2 equivalent of non-toxic cyanide source, K₄[Fe(CN)₆], 3 mol% AgI, 4 mol% PEG-400, and 3 mol% KI as the catalyst system is described. The reactions were performed in DMF at room temperature and provided the corresponding aroyl cyanides in 64-89% yield, typically in less than ten hours.

Key words

green chemistry - catalysis - synthesis - phase-transfer catalysis - cyanation

References and Notes

• 1a Saikia P. Laskar DD. Prajapati D. Sandhu JS. Tetrahedron Lett.  2002,  43:  7525 
• 1b Baek HS. Lee SJ. Yoo BW. Ko JJ. Kim SH. Kim JH. Tetrahedron Lett.  2000,  41:  8097 
• 1c Yoo BW. Kim DY. Choi JW. Hwang SK. Choi KI. Kim JH. Bull. Korean Chem. Soc.  2003,  24:  263 
• 2 Gohain M. Gogoi BJ. Prajapati D. Sandhu JS. New J. Chem.  2003,  27:  1038 
• 3 Yoo BW. Hwang SK. Kim DY. Choi JW. Ko JJ. Choi KI. Kim JH. Tetrahedron Lett.  2002,  43:  4813 
• 4 Duplais C. Bures F. Sapountzis I. Korn TJ. Cahiez G. Knochel P. Angew. Chem. Int. Ed.  2004,  43:  2968 
• 5 Yoo BW. Lee SJ. Choi KH. Keum SR. Ko JJ. Choi KI. Kim JH. Tetrahedron Lett.  2001,  42:  7287 
• 6 Veronese AC. Callegari R. Basato M. Valle G. J. Chem. Soc., Perkin Trans. 1  1994,  1779 
• 7 Park YS. Han JH. Yoo B. Choi KI. Kim JH. Yoon CM. Yoo BW. Bull. Korean Chem. Soc.  2005,  26:  878 
• 8 Okimoto M. Chiba T. Synthesis  1996,  1188 
• 9 Zhang W. Shi M. Org. Biomol. Chem.  2006,  4:  1671 
• 10 Watahiki T. Ohba S. Oriyama T. Org. Lett.  2003,  5:  2679 
• 11 Nemoto H. Ibaragi T. Bando M. Kido M. Shibuya M. Tetrahedron Lett.  1999,  40:  1319 
• 12 Zhou S. Yan B. Liu Y. J. Org. Chem.  2005,  70:  4006 
• 13 Liu YH. Yan B. Organometallics  2006,  25:  544 
• 14 Demko ZP. Sharpless KB. Angew. Chem. Int. Ed.  2002,  41:  2113 
• 15 Zhuo JC. Wyler H. Helv. Chim. Acta  1993,  76:  1916 
• 16 Connors R. Tran E. Durst T. Can. J. Chem.  1996,  74:  221 
• 17 Kuwabara H. Ushigoe Y. Nojima M. J. Chem. Soc., Perkin Trans. 1  1996,  871 
• 18 Hunig S. Schaller R. Angew. Chem., Int. Ed. Engl.  1982,  21:  36 
• 19 Koenig KE. Weber WP. Tetrahedron Lett.  1974,  2275 
• 20 Oakwood TS. Weisgerber CA. Org. Synth., Coll. Vol. 3   Wiley; New York: 1955.  p.112 
• 21a Tanaka M. Koyanagi M. Synthesis  1981,  973 
• 21b Cao YQ. Du YF. Chen BH. Li JT. Synth. Commun.  2004,  34:  2951 
• 21c Ando T. Kawate T. Yamawaki J. Hanafusa T. Synthesis  1983,  637 
• 22 Tanaka M. Tetrahedron Lett.  1980,  21:  2959 
• 23a Olah GA. Arvanaghi M. Prakash GKS. Synthesis  1983,  636 
• 23b Harle H. Jochims JC. Chem. Ber.  1986,  119:  1400 
• 24 Choudary BM. Reddy PN. J. Mol. Catal. A: Chem.  1996,  112:  385 
• 25a Schareina T. Zapf A. Beller M. Tetrahedron Lett.  2005,  46:  2585 
• 25b Schareina T. Zapf A. Beller M. J. Organomet. Chem.  2004,  689:  4576 
• 25c Schareina T. Zapf A. Beller M. Chem. Commun.  2004,  1388 
• 25d Weissman SA. Zewge D. Chen C. J. Org. Chem.  2005,  70:  1508 
• 25e Grossman O. Gelman D. Org. Lett.  2006,  8:  1189 

26

General Procedure: A mixture of AgI (0.1 g, 0.45 mmol), PEG400 (0.24 g, 0.6 mmol), KI (0.08 g, 0.45 mmol), and K₄[Fe(CN)₆] (1.15 g, 3 mmol) (dried at 80 °C under vacuum for 24 h and finely powdered prior to use) in anhyd DMF (10 mL) was first stirred for 10 min, then aroyl chloride (15 mmol) was added. The mixture was stirred for the appropriate time indicated in Table [2] at r.t. The progress of the reaction was monitored by TLC (PE-EtOAc, 5:1). Then CH₂Cl₂ (20 mL) was added. The suspension was filtered to remove the solid, the filtrate was washed with cold H₂O (3 × 30 mL), and dried over anhyd MgSO₄. Then the solvent was removed by distillation and the residue was crystallized from hexane to give the product. 2-Chlorobenzoyl cyanide: IR (KBr): 2089 (C≡N), 1776 cm^-1 (C=O). ¹H NMR (CDCl₃, 400 MHz): δ = 7.29-7.81 (m, 4 H, Ph). Anal. Calcd for C₈H₄ClNO: C, 58.03; H, 2.44; N, 8.46. Found: C, 57.91; H, 2.50; N, 8.39. 3-Chlorobenzoyl cyanide: IR (KBr): 1964 (C≡N), 1793 cm^-1 (C=O). ¹H NMR (CDCl₃, 400 MHz): δ = 7.22-7.78 (m, 4 H, Ph). Anal. Calcd for C₈H₄ClNO: C, 58.03; H, 2.44; N, 8.46. Found: C, 58.11; H, 2.49; N, 8.53. 2-Furoyl cyanide: IR (KBr): 2067 (C≡N), 1758 cm^-1 (C=O). ¹H NMR (CDCl₃, 400 MHz): δ = 6.70-7.69 (m, 3 H, Furan). Anal. Calcd. for C₆H₃NO₂: C, 59.51; H, 2.50; N, 11.57. Found: C, 59.70; H, 2.43; N, 11.49. 2-Thiophenecarbonyl cyanide: IR (KBr): 2052 (C≡N), 1766 (C=O). ¹H NMR (CDCl₃, 400 MHz): δ = 7.10-7.71 (m, 3 H, Thiophene). Anal. Calcd for C₆H₃NOS: C, 52.54; H, 2.20; N, 11.66. Found: C, 52.42; H, 2.30; N, 11.72.