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LETTER
(2) (a) Li, A.-H.; Dai, L.-X.; Aggarwal, V. K. Chem. Rev. 1997,
97, 2341. (b) Aggarwal, V. K.; Calamai, S.; Ford, J. G. J.
Chem. Soc., Perkin Trans. 1 1997, 593. (c) Aggarwal, V.
K.; Ford, J. G.; Fonquerna, S.; Adams, H.; Jones, R. V. H.;
Fieldhouse, R. J. Am. Chem. Soc. 1998, 120, 8328.
(d) Julienne, K.; Metzner, P.; Henryon, V. J. Chem. Soc.,
Perkin Trans. 1 1999, 731. (e) Aggarwal, V. K.; Winn, C. L.
Acc. Chem. Res. 2004, 37, 611.
with CHCl3 and sat. aq NH4Cl. The mixture was separated
and the aqueous layer was washed with H2O, brine, and then
dried over MgSO4. Removal of the solvent and purification
by flash chromatography (hexane–EtOAc = 1:1) afforded
N,N-diethyl-4-(3-phenyloxiranyl)benzamide (2d, 264 mg,
89%) as a colorless solid; mp 83–85 °C. 1H NMR (400 MHz,
CDCl3): d = 1.20 (m, 6 H), 3.30 (m, 2 H), 3.54 (m, 2 H), 3.86
(d, 1 H, J = 1.83 Hz), 3.88 (d, 1 H, J = 1.83 Hz), 7.32–7.41
(m, 9 H). 13C NMR (126 MHz, CDCl3): d = 13.0, 14.2, 39.3,
43.3, 62.4, 62.9, 125.6, 126.7, 128.5, 128.6, 136.9, 137.4,
138.2, 170.9. IR (CHCl3): nmax = 3000, 1612, 1565, 1510
cm–1. HRMS (EI+): m/z calcd for C19H21NO2: 295.1572;
found: 295.1572. Anal. Calcd for C19H21NO2: C, 77.25; H,
7.17; N, 4.74. Found: C, 77.13; H, 7.28; N, 4.71. DABCO
dissolved in the aqueous layer as an ammonium ion was
recovered when the aqueous layer was basified by KOH and
extracted with CH2Cl2.
(3) Jonczyk, A.; Konarska, A. Synlett 1999, 1085.
(4) Typical Procedure for the Preparation of p-Substituted
Benzyltriethylammonium Chlorides (1d).
A mixture of 4-chloromethyl-N,N-diethylbenzamide (2.25 g,
10 mmol) and Et3N (5.5 mL, 40 mmol) in acetone (5 mL)
was heated under reflux for 16 h. Acetone was removed in
vacuo and EtOAc was added. The formed colorless solid
was filtered off to afford 4-diethylcarbamyl-benzyltriethyl-
ammonium chloride (1d, 2.27 g, 6.95 mmol) in 70% yield as
white solid; mp 125–127 °C. 1H NMR (400 MHz, CDCl3):
d = 1.11 (m, 3 H), 1.26 (m, 3 H), 1.48 (t, 9 H, J = 7.3 Hz),
3.44 (m, 2 H), 3.47 (q, 8 H, J = 7.3 Hz), 5.03 (s, 2 H), 7.45
(d, 2 H, J = 8.4 Hz), 7.7 (d, 2 H, J = 8.1 Hz). 13C NMR (126
MHz, CDCl3): d = 8.5, 12.9, 14.3, 39.4, 43.4, 53.2, 61.1,
127.3, 128.4, 133.0, 139.6, 170.0. IR (CHCl3): nmax = 2900,
1615, 1565, 1510 cm–1. HRMS (FAB+): m/z calcd for
[C18H31N2O]+: 291.2436; found: 291.2434. Anal. Calcd for
C18H31N2OCl·H2O: C, 62.7; H, 9.65; N, 8.12. Found: C,
62.55; H, 9.99; N, 8.12.
(7) Quinuclidine (the second N of DABCO is replaced by CH)
was also tried as an amine candidate. The ammonium salt
was formed but it was too moisture sensitive to be isolated.
When one-pot and successive preparation of trans-2,3-diaryl
epoxide was carried out using quinuclidine, 2h was obtained
in 89%. Thus, the role of the second N of DABCO is not
clear to date.
(8) When carbonyl compounds such as aliphatic aldehydes and
ketones, other than aryl aldehydes were used under the
reaction condition, no epoxides were formed and carbonyl
compounds were recovered.
(5) Quaternary ammonium salts containing methyl groups are
known to promote 2,3-Stevens-type rearrangement reaction
under strong basic condition. See: Marko, I. E. In
Comprehensive Organic Synthesis, Vol. 3; Trost, B., Ed.;
Pergamon Press: Oxford England, 1991, 913.
(6) Typical Procedure.
(9) According to the literature method,10 we have tried the
reaction using benzylic chloride [e.g. (p-chloromethyl)benzo-
nitrile, p-nitrobenzyl chloride] and benzaldehyde in the
presence of phase-transfer catalyst. Corresponding epoxides
were obtained in 88% and 70%, respectively, as
To an ice cooled stirred solution of 4-diethylcarbamyl
benzyltriethylammonium chloride (1d, 326.8 mg, 1 mmol)
and benzaldehyde (0.1 mL, 1 mmol) in THF (4 mL) was
slowly added t-BuOK (224.4 mg, 2 mmol). Yellow colored
suspension was stirred for 1 h at r.t. The mixture was diluted
diastereomeric mixtures.
(10) (a) Dilling, W. L.; Hickner, R. A.; Farber, H. A. J. Org.
Chem. 1967, 32, 3489. (b) Taranko, L. B.; Perry, R. H. Jr. J.
Org. Chem. 1969, 34, 226.
Synlett 2005, No. 5, 842–844 © Thieme Stuttgart · New York