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S. K. Maiti et al. / Tetrahedron Letters 49 (2008) 6205–6208
Table 1
Details of olefin epoxidation using catalyst 4, NaHCO3 (25 mol %), H2O2 (3–5 equiv) and CH3CN as solvent at rt
Entry
Substrate
Product
Time (h)
% Conversion
% Yielda
% Yieldc
TONd
TOFe
GCb
Iso
—
1
0.17
99
99
25
14,825
89,100f
O
2
3
0.33
0.75
80
93
80
93
73
81
35
22
8000
4650
24,000f
6200f
O
O
O
4
5
1.00
0.75
99
80
99
80
—
—
20
25
3960
1600
3960
O
2133f
HO
HO
6
7
0.17
1.50
98
84
98
84
—
—
21
58
9800
4200
58,800f
2800
O
HO
HO
O
O
8
9
1.25
2.00
85
92
85
92
—
35
40
4250
4600
3400
2300
HO
HO
HO
HO
78
O
10
11
12
13
1.25
0.33
0.83
1.25
94
92
98
94
94
92
98
94
—
78
—
35
52
30
24
4700
4600
4900
4700
3700
O
O
13,800f
5904f
3760
OH
OH
O
O
83
OH
5733f
1240
OH
14
15
0.75
1.50
86
93
86
93
73
79
20
18
4300
1860
O
O
O
16
17
1.50
1.42
98
95
98
95
—
20
23
1960
1900
1306
1338
O
81
HO
HO
O
18
2.50
94
94
85
15
940
376
a
A control experiment (omission of 1 as well as HCO3À) did not show any conversion to epoxide or other probable products.
The detailed calculation of GC yield is given in the supplementary data.
This is the yield of control experiment, excluding the catalyst 1 only, but not NaHCO3 which remains in the reaction solution at the same 25 mol % concentration. When
b
c
the control experiment uses NaHCO3 at a catalytic concentration the conversion and yield % become negligible.
d
TON = ratio of moles of product (here epoxide) obtained to the moles of catalyst used.
e
The corresponding TOFs (TON hÀ1) are shown in the parentheses.
f
Values extrapolated. The mole ratio of catalyst:substrate = 1:15,000 (for entry 1), 10,000 (for entries 2 and 6), 5000 (for entries 3 and 7–14), 4000 (for entry 4), 2000 (for
entries 5, 15, 16 and 17), 1000 (for entry 17). For entries 15, 16, 17 and 18, acetonitrile and acetone solvent mixtures were used in 2:1 volume ratio. Values for 1H and 13C NMR
of the isolated epoxides are given below. (a) 1,2-Epoxycyclooctane: 1H NMR (CDCl3): d 1.25–1.29 (m, 2H), 1.43–1.68 (m, 8H), 2.12–2.17 (m, 2H), 2.87–2.93 (m, 2H); 13C NMR
(CDCl3): d 25.6, 26.3, 26.6, 55.7. (b) 1,2-Epoxycyclohexane: 1H NMR (CDCl3) d 0.89–1.05 (m, 4H), 1.45–1.58 (m, 4H), 3.1 (s, 2H); 13C NMR (CDCl3) d 19.4, 24.4, 52.1. (c) 4,5-
Epoxypentan-1-ol: 1H NMR (CDCl3): d 1.25–1.41 (m, 4H), 2.35 (dd, J1 = 2.77, J2 = 2.78 Hz, 2H), 2.62 (dd, J1 = 4.12, J2 = 4.85 Hz, 1H), 3.51 (br s, 1H), 4.01 (t, J = 5.67 Hz, 2H); 13
C
NMR (CDCl3): d 27.8, 31.8, 46.8, 52.3, 57.7. (d) 2,3-Epoxyhexan-1-ol: 1H NMR (CDCl3): d 0.73 (t, J = 7.3 Hz, 3H), 1.19–1.26 (m, 4H), 2.62–2.66 (m, 2H), 3.83 (d, J = 4.71 Hz, 2H),
4.07 (br s, 1H); 13C NMR (CDCl3): d 13.2, 25.2, 32.2, 57.4, 59.1, 62.6. (e) 1,2-Epoxyoctane: 1H NMR (CDCl3): d 0.81 (t, J = 6.5 Hz, 3H), 1.17–1.55 (m, 10H), 2.45 (dd, J1 = 1.43,
J2 = 1.59 Hz, 1H), 2.73 (dd, J1 = 2.96, J2 = 3.49 Hz, 1H), 2.91 (m, 1H); 13C NMR (CDCl3): d 13.9, 22.5, 25.8, 29.0, 31.7, 32.4, 47.1, 52.1. (f) 1,2-Epoxyoctan-3-ol: 1H NMR (CDCl3): d
0.77 (t, J = 6.8 Hz, 3H), 1.15–1.41 (m, 8H), 1.85 (m, 1H), 2.57 (dd, J1 = 1.87, J2 = 2.15 Hz, 1H), 2.61 (dd, J1 = 2.29, J2 = 2.66 Hz, 1H), 2.89 (m, 2H); 13C NMR (CDCl3): d 13.6, 22.3,
24.8, 27.8, 31.8, 46.7, 52.1, 72.6. (g) 1,2-Epoxydecane: 1H NMR (CDCl3): d 0.88 (t, J = 6.6 Hz, 3H), 1.28–1.53 (m, 14H), 2.15 (dd, J1 = 1.5 Hz, 1H), 2.73 (dd, J1 = 4.9, J2 = 5.7 Hz, 1H),
2.88–2.89 (m, 1H). 13C NMR (CDCl3): d 14.1, 22.7, 26.1, 29.3, 29.4, 29.6, 31.9, 32.6, 47.0, 52.4. (h) 9,10-Epoxydecan-1-ol: 1H NMR (CDCl3): d 1.14–1.37 (m, 14H), 1.91 (m, 1H),
2.55 (dd, J1 = 4.04, J2 = 4.84 Hz, 1H), 2.73 (dd, J1 = 2.73, J2 = 3.89 Hz, 1H), 3.36 (t, J = 6.74 Hz, 2H), 3.80 (m, 1H). 13C NMR (CDCl3): d 22.3, 25.6, 28.7, 29.1, 31.5, 32.3, 33.4, 46.5,
51.9, 61.9. (i) 1,2-Epoxydodecane: 1H NMR (CDCl3): d 0.88 (t, J = 6.8 Hz, 3H), 1.26–1.56 (m, 18H), 2.44 (dd, J1 = 2.70, J2 = 2.73 Hz, 2H), 2.73 (dd, J1 = 4.23, J2 = 4.83 Hz, 1H), 2.86–
2.92 (m, 1H). 13C NMR (CDCl3): d 14.1. 22.7, 26.1, 29.4, 29.5, 29.6 (double intensity), 29.7, 31.9, 32.6, 47.1, 52.4, 58.2. NMR spectra of the products corresponding to entries 4, 5
and 12 are superimposable with the literature data. Electrospray mass spectra: (a) 1,2-Epoxydecane: ES MS m/z (rel. int.%): 197.21 [M+CH3CN]+ (47), 156.15 [M]+ (9), 128.12
[C8H16O]+ (100). (b) 9,10-Epoxydecan-1-ol: ES MS m/z (rel. int.%): 213.21 [M+CH3CN]+ (64), 195.07 [M+Na]+ (100), 172.15 [M]+ (13).