5
90
Y. Fukuda et al.
SHORT PAPER
6
The two active intermediates in the present system are as- The physical data of the known cyanohydorins shown below were
comparable to those of the corresponding literature: cyclohexyl-
sumed to be the hypervalent silicate 10, which was formed
8
8
9
hydroxyacetonitrile, 2-hydroxy-3,3-dimethylbutyronitrile,
from the N-heterocyclic carbene 2 and trimethylsilyl cya-
nide (Scheme 1), and the species 12, which was formed
from 2 and aldehyde (Scheme 2).
8
hydroxyphenylacetonitrile, (4-fluorophenyl)hydroxyacetonitrile,
1
0
hydroxy(4-methoxyphenyl)acetonitrile.
2
-Hydroxy-4,4-dimethylpentanenitrile
Colorless oil.
N
N
IR (neat): 3440, 2247 cm–1.
2
Ar
Ar
RCHO
MeSiCN
1
Me3Si CN
H NMR (CDCl ): d = 1.02 (s, 9 H), 1.80–1.86 (m, 2 H), 2.72 (br s,
3
10
1 H), 4.54 (t, J = 6.6 Hz, 1 H).
1
3
C NMR (CDCl ): d = 29.66, 30.14, 48.78, 58.89, 120.80.
3
+
O–
N
N
OTMS
CN
+
Ar
Ar
SiMe3
EI–MS: m/z = 127 [M ], 115, 85, 57 (base peak).
R
CN
R
HRMS: m/z calcd for C H NO: 127.09972; found: 127.09775.
7
13
11
Scheme 1 Possible reaction mechanism 1
References
(
1) For reviews: (a) César, V.; Bellemin-Laponnaz, S.; Gade, L.
H. Chem. Soc. Rev. 2004, 33, 619. (b) Herrmann, W. A.
Angew. Chem. Int. Ed. 2002, 41, 1291.
2) For reviews: (a) Nair, V.; Bindu, S.; Sreekumar, V. Angew.
Chem. Int. Ed. 2004, 43, 5130. (b) Grasa, G. A.; Singh, R.;
Nolan, S. P. Synthesis 2004, 971. For examples:
O
OTMS
H
CN–
OTMS
CN
TMSCN
Ar
R
R
H
(
ArN
NAr
+
R
Ar
12
N
N
(
c) Connor, E. F.; Nyce, G. W.; Myers, M.; Möck, A.;
Scheme 2 Possible reaction mechanism 2
Hedrick, J. L. J. Am. Chem. Soc. 2002, 124, 914. (d) Grasa,
G. A.; Kissling, R. M.; Nolan, S. P. Org. Lett. 2002, 4, 3583.
(
e) Suzuki, Y.; Toyota, T.; Imada, F.; Sato, M.; Miyashita,
In summary, the N-heterocyclic carbene 2 was found to
function as catalyst in cyanosilylation reactions of alde-
hydes with trimethylsilyl cyanide. Ongoing efforts are fo-
cused on developing an asymmetric version of this
reaction with a chiral N-heterocyclic carbene.
A. Chem. Commun. 2003, 1314. (f) Singh, R.; Kissling, R.
M.; Letellier, M.-A.; Nolan, S. P. J. Org. Chem. 2004, 69,
2
Soc. 2004, 126, 14370. (h) Burstein, C.; Glorius, F. Angew.
Chem. Int. Ed. 2004, 43, 6205. (i) Kano, T.; Sasaki, K.;
Maruoka, K. Org. Lett. 2005, 7, 1347.
09. (g) Sohn, S. S.; Rosen, E. L.; Bode, J. W. J. Am. Chem.
7
(
(
3) For a review: Gregory, R. J. H. Chem. Rev. 1999, 99, 3649.
4) (a) Green, T. W.; Wuts, P. G. M. Protective Groups in
Organic Synthesis, 3th ed.; John Wiley and Sons, Inc.: New
York, 1999, 348–349. (b) Rasmussen, J. K.; Heilmann, S.
M.; Krepski, L. R. Advances in Silicon Chemistry, Vol. 1;
Larson, G. L., Ed.; Jai Press Inc.: England, 1991, 75–86.
5) Kobayashi, S.; Tsuchiya, Y.; Mukaiyama, T. Chem. Lett.
1991, 537.
IR spectra were measured on a JASCO IR Report-100 diffraction
1
13
grating IR spectrophotometer. H NMR (270 MHz) and C NMR
68 MHz) spectra were measured on a JEOL JNM-EX-270 NMR
spectrometer. EI MS spectra were measured on a JEOL JMS-SX-
02A instrument. Commercially available aldehydes and reagents
(
1
were used without any purification. Tetrahydrofuran was distilled
(
from Na/benzophenone ketyl under a N atmosphere. DMF was dis-
2
tilled from CaH under reduced pressure. Silica gel column chroma-
2
(6) In the absence of t-BuOK, reaction with hydrocinnam-
aldehyde (3) as a substrate and 10 mol% of the imidazolium
chloride 1 did not completely proceed even after 1 h at r.t.
For an imidazolium salt (ionic liquid)-mediated
tography was performed on Fuji silysia PSQ 60B.
Cyanosilylation; Typical Procedure
To a stirred solution of hydrocinnamaldehyde (3; 67.1 mg, 0.50
mmol), TMSCN (59.5 mg, 0.60 mmol), and 1,3-bis(2,4,6-trimeth-
ylphenyl)imidazolium chloride (1; 17.0 mg, 0.050 mmol) in THF
cyanosilylation reaction, see: Shen, Z.-L.; Ji, S.-J.; Loh, T.-
P. Tetrahedron Lett. 2005, 46, 3137.
(7) For examples: (a) Hamashima, Y.; Sawada, D.; Kanai, M.;
(2.0 mL) was added t-BuOK (5.1 mg, 0.045 mmol) at r.t. The mix-
Shibasaki, M. J. Am. Chem. Soc. 1999, 121, 2641.
ture was stirred for 5 min at r.t., quenched with 1 N HCl, and ex-
tracted with EtOAc. The organic extracts were washed with brine,
dried (Na SO ), and concentrated. Purification by silica gel column
(
b) Belokon’, Y. N.; Caveda-Cepas, S.; Green, B.;
Ikonnikov, N. S.; Khrustalev, V. N.; Larichev, V. S.;
Timofeeva, G. I.; Yashkina, L. V. J. Am. Chem. Soc. 1999,
2
4
chromatography (EtOAc–hexane, 1:5) gave 2-hydroxy-4-phenyl-
butyronitrile (72.7 mg, 90%) as a colorless oil. The physical data
121, 3968; and references cited therein.
(
(
8) Watahiki, T.; Ohba, S.; Oriyama, T. Org. Lett. 2003, 5, 2679.
9) Sidney, L.; Xiu, R. B. J. Org. Chem. 2002, 67, 2702.
8
were comparable to those reported in the literature.
(
10) Hayashi, M.; Miyamoto, Y.; Inoue, T.; Oguni, N. J. Org.
Chem. 1993, 58, 1515.
Synthesis 2006, No. 4, 589–590 © Thieme Stuttgart · New York