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LETTER
(4) Sundermeier, M.; Zapf, A.; Beller, M. Eur. J. Inorg. Chem.
2003, 3513.
(12) As the ionic liquid, [BMIm]BF4 was chosen because it was
not only most easily manipulated at r.t., but one can be sure
to be able to separate the product from the solvent
completely via simple extraction with a conventional
organic solvent and reused.
(5) (a) Okano, M.; Amano, M.; Takagi, K. Tetrahedron Lett.
1998, 39, 3001. (b) Ramnauth, J.; Bhardwaj, N.; Renton, P.;
Rhakit, S.; Maddafird, S. Synlett 2003, 2237. (c) Tschaen,
D. M.; Desmond, R.; King, A. O.; Forin, M. C.; Pipik, B.;
King, S.; Verhoeven, T. R. Synth. Commun. 1994, 24, 887.
(d) Marcantonio, K. M.; Frey, L. F.; Liu, Y.; Chen, Y.;
Strine, J.; Phenix, B.; Wallace, D. J.; Chen, C.-Y. Org. Lett.
2004, 6, 3723. (e) Maligres, P. E.; Waters, M. S.; Fleitz, F.;
Askin, D. Tetrahedron Lett. 1999, 40, 8193. (f) Jiang, B.;
Kan, Y.; Zhang, A. Tetrahedron 2001, 57, 1581.
(13) K4[Fe(CN)6]·3H2O is ground to a fine powder and dried
under vacuum (ca. 2 mbar) at 80 °C overnight.
(14) Microwave experiments were conducted using a CEM
Discover Synthesis Unit (CEM Corp., Matthews, NC). The
machine consists of a continuous focused microwave power
delivery system with operator selectable power output from
0–300 W.
(6) (a) Chidambaram, R. Tetrahedron Lett. 2004, 45, 1441.
(b) Jin, F.; Confalone, P. N. Tetrahedron Lett. 2000, 41,
3271. (c) Okano, T.; Iwahara, M.; Kiji, J. Synlett 1998, 243.
(d) Stazi, F.; Palmisano, G.; Turconi, M.; Santagostino, M.
Tetrahedron Lett. 2005, 46, 1815. (e) Hatsuda, M.; Seki, M.
Tetrahedron Lett. 2005, 46, 1849. (f) Grossman, O.;
Gelman, D. Org. Lett. 2006, 8, 1189.
(7) (a) Okano, T.; Kiji, J.; Toyooka, Y. Chem. Lett. 1998, 425.
(b) Cassar, L.; Foa, M. J. Organomet. Chem. 1979, 173,
335. (c) Sundermeier, M.; Zapf, A.; Beller, M. Angew.
Chem. Int. Ed. 2003, 42, 1661. (d) Sundermeier, M.;
Mutyala, S.; Zapf, A.; Spannenberg, A.; Beller, M. J.
Organomet. Chem. 2003, 684, 50. (e) Yang, C.; Williams, J.
M. Org. Lett. 2004, 6, 2837.
(8) (a) First use of potassium ferrocyanide in this capacity
(uncatalyzed reaction): Merz, V.; Weith, W. Ber. Dtsch.
Chem. Ges. 1877, 10746. (b) Schareina, T.; Zapf, A.; Beller,
M. Chem. Commun. 2004, 12, 1388. (c)Schareina, T.; Zapt,
A.; Beller, M. J. Organomet. Chem. 2004, 689, 4576.
(d) Schareina, T.; Zapf, A.; Beller, M. Tetrahedron Lett.
2005, 46, 2585. (e) Weissman, S. A.; Zewge, D.; Chen, C. J.
Org. Chem. 2005, 70, 1508.
(15) For recent examples, see: (a) Ho, T.-L.; Su, C.-Y. J. Org.
Chem. 2000, 65, 3566. (b) Williams, G. M.; Roughley, S.
D.; Davies, J. E.; Holmes, A. B. J. Am. Chem. Soc. 1999,
121, 4900. (c) Carless, H. A. J.; Dove, Y. Tetrahedron:
Asymmetry 1996, 7, 649.
(16) (a) Fleming, F. F.; Pu, Y.; Tercek, F. J. Org. Chem. 1997, 62,
4883. (b) Fleming, F. F.; Hussain, Z.; Weaver, D.; Norman,
R. E. J. Org. Chem. 1997, 62, 1305. (c) Fleming, F. F.; Pak,
J. J. J. Org. Chem. 1995, 60, 4299.
(17) General Procedure for the Cyanation of Aryl and
Arylvinyl Bromides under Microwave Promotion.
[BMIm]BF4 (1.5 mL) was placed into a 10-mL glass
microwave tube and to this was added anhyd K4[Fe(CN)6]
(0.05 mmol), Na2CO3 (0.25 mmol), substrate (0.25 mmol),
PdCl2 (2.5 mol%), and DMEDA (10 mol%). After sealing
the tube, the mixture was exposed to microwave irradiation
(a maximum microwave power of 120 W, a temperature
threshold of 200 °C and a pressure threshold of 200 psi) for
the requisite time. After the reaction mixture was cooled, the
product was extracted from the system by washing the ionic
liquid repeatedly with EtOAc–PE = 8:1 (4 × 3 mL). Finally,
the product was isolated by flash chromatography on silica
gel using EtOAc–PE as mobile phase.
(9) (a) Wasserscheid, P.; Welton, T. Ionic Liquids in Synthesis;
Wiley-VCH: Weinheim, 2002. (b) Liao, M. C.; Duan, X. H.;
Liang, Y. M. Tetrahedron Lett. 2005, 46, 3469.
(18) Compound 2a: 1H NMR (300 MHz, CDCl3): d = 7.72–7.65
(m, 4 H), 7.60–7.56 (m, 2 H), 7.51–7.41 (m, 3 H) ppm. 13
C
(10) Wu, J. X.; Beck, B.; Ren, R. X. Tetrahedron Lett. 2002, 43,
387.
NMR (75 MHz, CDCl3): d = 145.5, 139.0, 132.5, 129.0,
128.6, 127.6, 127.1, 118.9, 110.7 ppm. MS: m/z = 179 [M+],
151, 76.
(11) (a) Leadbeater, N. E.; Torenius, H. M.; Tye, H. Tetrahedron
2003, 59, 2253. (b) Cai, L.; Liu, X.; Tao, X.; Shen, D. Synth.
Commun. 2004, 34, 1215. (c) Srivastava, R. R.; Collibee, S.
E. Tetrahedron Lett. 2004, 45, 8895. (d) Arvela, R. K.;
Leadbeater, N. E. J. Org. Chem. 2003, 68, 9122. (e)Arvela,
R. K.; Leadbeater, N. E.; Torenius, H. M.; Tye, H. Org.
Biomol. Chem. 2003, 1, 1119. (f) Alterman, M.; Hallberg,
A. J. Org. Chem. 2000, 65, 7984.
Compound 2c: 1H NMR (300 MHz, CDCl3): d = 7.81–7.78
(m, 4 H), 7.71 (d, J = 8.7 Hz, 4 H) ppm. 13C NMR (75 MHz,
CDCl3): d = 143.4, 132.8, 127.9, 118.4, 112.3 ppm. MS:
m/z = 204 [M+], 153, 126, 76.
Compound 4d: 1H NMR (300 MHz, CDCl3): d = 8.22 (d,
J = 16.5 Hz, 1 H), 8.03 (d, J = 8.1 Hz, 1 H), 7.95–7.87 (m,
2 H), 7.67–7.46 (m, 4 H), 5.96 (d, J = 16.5 Hz, 1 H) ppm.
13C NMR (75 MHz, CDCl3): d = 147.8, 133.5, 131.5, 130.8,
130.6, 128.8, 127.3, 126.5, 125.3, 124.6, 122.7, 118.2, 98.7
ppm. MS: m/z = 179 [M+], 152, 76.
Synlett 2006, No. 13, 2094–2098 © Thieme Stuttgart · New York