7156
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B. D. Anal. Biochem. 2001, 299, 54; (d) Wheelock, C. E.; Wheelock, A. M.; Zhang,
13. Arduengo, A. J.; Krafczyk, R.; Schmutzler, R. Tetrahedron 1999, 55, 14523.
14. Typical procedure for cyanation of aldehydes with ethyl cyanoformate (Table 2
R.; Stok, J. E.; Morisseau, C.; LeValley, S. E.; Green, C. E.; Hammock, B. D. Anal.
Biochem. 2003, 315, 208; (e) Brunel, J. M.; Holmes, I. P. Angew. Chem., Int. Ed.
2004, 43, 2752; (f) Chen, F. X.; Feng, X. M. Synlett 2005, 892; (g) Liu, X. H.; Lin, L.
L.; Feng, X. M. Chem. Commun. 2009, 41, 6145.
entry 1): To a stirred solution of aldehyde 7a (48.0
lL, 0.5 mmol, 1.0 equiv) in
THF (2.0 mL) was added ethyl cyanoformate (98.0
lL, 1.0 mmol, 2.0 equiv) at
room temperature under argon atmosphere. After that the solution was then
cooled to 0 °C and IPr (2.0 mg, 1 mol %) was added. The mixture was stirred at
room temperature until the starting aldehyde was fully consumed as indicated
by TLC concentration and the crude material was purified by column
chromatography (PE-EtOAc: 9:1) to afford product 8a (100 mg, 98%) as a
colorless oil. 1H NMR (400 MHz CDCl3): d 7.59–7.53 (m, 2H), 7.49–7.44 (m, 3H),
6.27 (s, 1H), 4.37–4.23 (m, 2H), 1.35 (t, J = 7.1 Hz, 3H), 13C NMR (100 MHz,
CDCl3) d 153.65, 131.45, 130.85, 129.50, 128.10, 115.96, 66.58, 65.85, 14.34;
GC–MS (EI) m/z 205.0 [M]+.
9. For reviews on cyanation reactions, see: (a) Veum, L.; Kuster, M.; Telalovic, S.;
Hanefeld, U.; Maschmeyer, T. Eur. J. Org. Chem. 2002, 1516; (b) Gröger, H. Chem.
Eur. J. 2001, 7, 5246; (c) North, M. Tetrahedron: Asymmetry 2003, 14, 147; (d)
Belokon, Y. N.; Blacker, A. J.; Carta, P.; Clutterbuck, L. A.; North, M. Tetrahedron
2004, 60, 10433; (e) Yamagiwa, N.; Tian, J.; Matsunaga, S.; Shibasaki, M. J. Am.
Chem. Soc. 2005, 127, 3413; (f) Lundgren, S.; Wingstrand, E.; Moberg, C. Adv.
Synth. Catal. 2007, 349, 364; (g) Khan, N. H.; Kureshy, R. I.; Abdi, S. H. R.;
Agrawal, S.; Jasra, R. V. Coord. Chem. Rev. 2008, 252, 593.
10. For selected examples of catalytic asymmetric cyanations, see: (a) Hu, X. H.;
Nicewicz, D. A.; Johnson, J. S. Org. Lett. 2002, 4, 2957; (b) Lundgren, S.;
Wingstrand, E.; Penhoat, M.; Moberg, C. J. Am. Chem. Soc. 2005, 127, 11592; (c)
Gou, S. H.; Chen, X. H.; Xiong, Y.; Feng, X. M. J. Org. Chem. 2006, 71, 5732; (d)
Belokon, Y. N.; Ishibashi, E.; Nombra, H.; North, M. Chem. Commun. 2006, 16,
1775; (e) Gou, S. H.; Wang, J.; Liu, X. H.; Wang, W. T.; Chen, F. X.; Feng, X. M.
Adv. Synth. Catal. 2007, 349, 343; (f) Abell, J. P.; Yamamoto, H. J. Am. Chem. Soc.
2009, 131, 15118; (g) Wang, J.; Wang, W. T.; Li, W.; Hu, X. L.; Shen, K.; Tan, C.;
Liu, X. H.; Feng, X. M. Chem. Eur. J. 2009, 15, 11642; (h) Aoki, S.; Kotani, S.;
Sugiura, M.; Nakajima, M. Tetrahedron Lett. 2010, 51, 3547; (i) Khan, N. H.;
Agrawal, S.; Kureshy, R. I.; Abdi, S. H. R.; Pathak, K.; Bajaj, H. C. Chirality 2010,
22, 153; (j) Zhang, Z. P.; Wang, Z.; Zhang, R. Z.; Ding, K. L. Angew. Chem., Int. Ed.
2010, 49, 6746.
15. The addition of benzaldehyde to acetyl cyanide in THF under optimal
conditions that are used for cyanation with ethyl cyanoformate, isolated only
35% yield of the product. After a brief survey of solvents, catalyst loading and
other reaction conditions, we found that in the presence of 10 mol % IPr, the
cyano-acylation of aldehydes worked well in dichloroethane and afforded
acylated cyanohydrins in high yields. See Supplementary data for details of
reaction procedure.
16. Typical procedure for cyanation reaction with acetyl cyanide (Table 3 entry 6): To
a stirred solution of aldehyde 7f (70.0 mg, 0.5 mmol, 1.0 equiv) in 1,2-DCE
(2.0 mL) was added acetyl cyanide (80.0 lL, 1.0 mmol, 2.0 equiv) at room
temperature under argon atmosphere. After that the solution was then cooled
to 0 °C and IPr (19.4 mg, 10 mol %) was added. The mixture was stirred at room
temperature until the starting aldehyde was fully consumed as indicated by
TLC concentration, the crude material was purified by column chromatography
(PE-EtOAc: 15:1) to afford product 10f (92 mg, 82%) as a colorless oil. 1H NMR
(400 MHz, CDCl3) d 7.49–7.45 (m, 2H), 7.45–7.41 (m, 2H), 6.38 (s, 1H), 2.17 (s,
3H); 13C NMR (100 MHz, CDCl3) d 168.78, 136.64, 130.26, 129.52, 129.27,
115.77, 62.15, 20.43; GC–MS: (EI) m/z 209.0 [M]+.
11. (a) Iwanami, K.; Hinakubo, Y.; Oriyama, T. Tetrahedron Lett. 2005, 46, 5881; (b)
Peng, D.; Zhou, H.; Liu, X. H.; Wang, L. W.; Chen, S. K.; Feng, X. M. Synlett 2007,
2448; (c) Chinchilla, R.; Nájera, C.; Ortega, F. J. Tetrahedron: Asymmetry 2008,
19, 265; (d) Khan, N. H.; Agrawal, S.; Kureshy, R. I.; Abdi, S. H. R.; Sadhukhan, A.;
Pillai, R. S.; Bajaj, H. C. Catal. Commun. 2010, 11, 907.
12. (a) Du, G. F.; He, L.; Gu, C. Z.; Dai, B. Synlett 2010, 2513; (b) Cai, Z. H.; Du, G. F.;
He, L.; Gu, C. Z.; Dai, B. Synthesis 2011, 13, 2073.