The Journal of Organic Chemistry
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51.5. EM (EI+, 70 eV): m/z (rel abund) 54 (42), 67 (37), 79 (75), 81
attributed to interferences of surface phenomena on the
reaction course. Silica-supported peracid 2a is recyclable by
treating the consumed reagent with 30% hydrogen peroxide in
acid medium.
(100), 95 (17), 109 (5), 110 (3, [M•+]).
1
(Z)-3-Methylpentene Oxide (3e) [1447-39-8]. H NMR (300
MHz, CDCl3) δ 0.9 (3H, t, J = 7.5 Hz), 1.2 (3H, s), 1.3 (3H, d, J = 5.5
Hz), 1.5 (1H, dq, J1 = 7.5 Hz, J2 = 13.8 Hz), 1.6 (1H, dq, J1 = 7.5 Hz,
J2 = 13.8 Hz), 2.9 (1H, q, J = 5.5 Hz); 13C NMR (75 MHz, CDCl3) δ
9.2, 14.1, 15.8, 31.3, 59.0, 62.0. EM (EI+, 70 eV): m/z (rel abund) 41
(100), 43 (63), 45 (22), 56 (47), 72 (71), 85 (2), 100 (1, [M•+]).
EXPERIMENTAL SECTION
■
General. Reagents and solvents were purified following standard
procedures.13 Alkenes 1 were commercial, except alkenyl acetates,
which were prepared by standard procedures. The glassware used in
the reactions with hydrogen peroxide was carefully cleaned and
washed before use with a solution of EDTA in ultrapure water (0.25 g
L−1) to remove any traces of metals. Commercial 65−70% MCPBA
(2b) was purified by treatment with an aqueous buffer solution of
KH2PO4/K2HPO4 with pH 7.5. The solid was filtered and
recrystallized from a 1:3 diethyl ether/n-hexane mixture to yield
99.9% MCPBA (2b), as shown by iodometric titration.
1
1-Hexene Oxide (3f) [592-41-6]. H NMR (300 MHz, CDCl3):
δ 0.9 (3H, t, J = 7 Hz), 1.3−1.6 (6H, m), 2.5 (1H, dd, J1 = 2.8 Hz, J2 =
4.9 Hz), 2.8 (1H, dd, J1 = 4.1 Hz, J2 = 4.9 Hz), 2.9 (1H, d sext, J1 = 2.8
Hz, J2 = 4.0 Hz, J3 = J4 = 5.5 Hz); 13C NMR (75 MHz, CDCl3) δ 13.9,
22.4, 28.0, 32.0, 47.3, 52.7. EM (EI+, 70 eV): m/z (rel abund) 39 (18),
41 (42), 42 (43), 55 (39), 58 (33), 71 (100), 85 (7), 99 (1), 100 (0,
[M•+]).
2-Phenylpropene Oxide (3g) [4436-24-2]. 1H NMR (300
MHz, CDCl3) δ 2.5 (1H, dd, J1 = 2.7 Hz, J2 = 5.0 Hz), 2.7−2.9 (3H,
m), 3.1 (1H, dsext, J1 = 2.7 Hz, J2 = 3.9 Hz, J3 = J4 = 5.5 Hz), 7.1−7.2
(5H, m); 13C NMR (75 MHz, CDCl3) δ 38.6, 46.7, 52.3, 126.5, 128.4,
128.8, 137.0. EM (EI+, 70 eV): m/z (rel abund) 44 (30), 50 (12), 65
(25), 78 (21), 91 (100), 104 (35), 117 (13), 134 (55, [M•+]).
[2-Percarboxyethyl] Functionalized Silica (2a). A suspension
of 3 g of [2-carboxyethyl] functionalized silica (2.6 mmol g−1) in 7.5
mL of 70% H2SO4 was allowed to stir at 5 °C for 30 min. Then, 2.5
mL of 30% hydrogen peroxide was added at once, and the mixture was
allowed to react at 0 °C under stirring for 6 h. The solid was filtered
and washed with cold bidistilled water until the filtrate showed a
negative peroxide test. The solid was dried under vacuum at room
temperature until constant weight. Standard iodometric titration
determined a peroxide content of 1.2 mmol g−1 of material.
1
1-Hydroxy-2-cyclohexene Oxide (3h) [1192-78-5]. H NMR
(300 MHz, CDCl3) δ 1.2−1.3 (2H, m), 1.4−1.6 (2H, m), 1.7−1.9
(2H, m), 2.0 (1H, broad s, OH), 3.3−3.4 (2H, m), 4.0 (1H, ddd, J1 =
2.9 Hz, J2 = 4.7 Hz, J3 = 7.4 Hz); 13C NMR (75 MHz, CDCl3) δ 18.1,
23.1, 28.9, 55.3, 55.4, 67.0. EM (EI+, 70 eV): m/z (rel abund) 41 (20),
57 (74), 58 (37), 60 (7), 70 (100), 83 (4), 95 (6), 114 (0, [M•+]).
1-Hydroxymethyl-3-cyclohexene Oxide (3i) [767-11-3]. Mix-
Oxidation of Alkenes 1 with Silica-Supported Peracid 2a.
General Procedure. To a stirred 0.03 M solution of 2-cyclohexenol
1h (20 mL, 0.6 mmol) in dichloromethane, at room temperature was
added 1.0 g of anhydrous solid peracid 2a (1.2 mmol peracid g−1, 1.2
mmol) at once. The reaction was stirred at room temperature for 1 h
and was monitored by gas chromatography by withdrawing, filtering,
and analyzing 0.1 mL aliquots at regular times. Once the reaction was
complete, the mixture was filtered, and the solid was thoroughly
washed with dichloromethane. The organic solution was treated with
anhydrous magnesium sulfate, the solvent was evaporated under
vacuum, and the residue was dissolved in deuterochloroform and
1
ture of isomers 50:50. H NMR (300 MHz, CDCl3) δ 0.9−1.2 (1H,
m), 1.3−1.9 (6H, m), 2.0−2.2 (2H, m), 3.1−3.2 (2H, m), 3.3−3.5
(2H, m); 13C NMR (75 MHz, CDCl3) δ 20.8, 23.0, 23.6, 24.5, 27.0,
27.9, 32.5, 35.2, 51.4, 51.9, 52.7, 52.8, 67.3, 67.6; EM (EI+, 70 eV): m/
z (rel abund) isomer 1 41(96), 55(54), 57 (50), 67 (75), 69 (54), 79
(56), 84 (93), 97(100), 109(11), 128 (2,[M•+]); isomer 2 41 (100),
55(57), 57(60), 67 (73), 69 (51), 79 (64), 84 (93), 97 (100), 109 (9),
127 (1) 128 (1,[M•+]).
1
(E)-1-Hydroxy-5-hexene Oxide (3j) [106498-75-3]. H NMR
1
analyzed by H and 13C NMR.
(300 MHz, CDCl3) δ 0.9 (3H, t, J = 7.3 Hz), 1.4−1.6 (5H, m), 2.9−
3.0 (2H, m), 3.6 (1H, dd, J1 = 4.6 Hz, J2 = 12.7 Hz), 3.9 (1H, dd, J1 =
2.4 Hz, J2 = 12.7 Hz); 13C NMR (75 MHz, CDCl3) δ 13.8, 19.1, 33.4,
56.2, 58.8, 61.7. EM (EI+, 70 eV): m/z (rel abund) 41 (40), 43 (46),
55 (100), 57 (31), 73 (31), 83 (4), 98 (1), 116 (0, [M•+]).
Competitive Experiments. General Procedure. To 3 mL of a
0.01 M dichloromethane solution of 1a and 1h and 0.005 M of
adamantane, thermostatted at 20 °C was added either 25 mg of solid
peracid 2a (1.2 mmol g−1, 0.03 mmol) or 0.3 mL of a thermostatted
0.1 M dichloromethane solution of MCPBA (2b). The reaction
mixture was stirred for 6 h. The heterogeneous reaction mixture was
filtered, the solid was thoroughly washed with dichloromethane, and
the organic solution was analyzed by gas chromatography. For the
homogeneous reaction, the solution was directly analyzed by gas
chromatography. Substrate conversions were obtained from the peak
areas of the starting materials and the internal standard.
1
1-Hydroxy-5-hexene Oxide (3k) [21915-57-1]. H NMR (300
MHz, CDCl3) δ 1.4−1.7 (6H, m), 2.5 (1H, dd, J1 = 2.8 Hz, J2 = 4.9
Hz), 2.8 (1H, d, J = 4.1 Hz), 2.9−3.0 (1H, m), 3.7 (2H, t, J = 6.2 Hz),
6.1 (1H, broad s, OH); 13C NMR (75 MHz, CDCl3) δ 22.2, 32.0,
32.1, 47.1, 52.4, 62.5. EM (EI+, 70 eV): m/z (rel abund) 41 (28), 43
(15), 55 (9), 57 (26), 67 (20), 85 (100), 105 (2), 116 (1, [M•+]).
1-Methylcarbonyloxy-2-cyclohexene Oxide (3l) [84414-68-
6]. Mixture of isomers 60:40. 1H NMR (300 MHz, CDCl3) δ 1.1−1.6
(6.7H, m), 1.7−1.9 (4H, m), 1.9−2.0 (1.5H, m), 2.1 (5.2H, ds), 3.0
(1H, d, J = 3.6 Hz), 3.1−3.2 (1H, m), 3.2−3.3 (1.3H, m), 5.0(1H, t, J
= 7 Hz), 5.1 (1H, ddd, J1 = 1.7 Hz, J2 = 5.1 Hz, J3 = 9.1 Hz); 13C NMR
(75 MHz, CDCl3) δ major isomer 14.4, 21.1, 23.6, 25.7, 52.5, 53.3,
68.0, 170.1, minor isomer 19.3, 21.1, 22.5, 24.4, 52.8, 54.2, 70.8, 170.8.
EM (EI+, 70 eV): m/z (rel abund) major isomer 43 (100), 55 (18), 68
(18), 70 (54), 86 (9), 96 (17), 112 (21), 156 (0, [M•+]); minor isomer
43 (100), 55 (14), 67 (18), 70 (61), 86 (5), 96 (19), 112 (24), 156 (0,
[M•+]).
1-Methylcarbonyloxymethyl-3-cyclohexene Oxide (3m)
[75228-31-8]. Mixture of isomers 50:50. 1H NMR (300 MHz,
CDCl3) δ 0.9−1.2 (1.30 H, m), 1.3−1.9 (5H, m), 2.0−2.1 (4.5H, s),
2.1−2.2 (1.1H, m), 3.1−3.2 (2H, m), 3.82 (1H, d, J = 6.0 Hz), 3.86
(1H, dd, J1 = 2.2 Hz, J2 = 6.5 Hz); 13C NMR (75 MHz, CDCl3) δ 20.8,
21.0, 22.8, 23.6, 24.5, 27.0, 28.1, 29.3, 32.1, 51.0, 51.6, 52.3, 52.4, 68.3,
68.5, 171.07, 171.09. EM (EI+, 70 eV): m/z (rel abund) isomer 1 43
(100), 55 (22), 67 (44), 81 (85), 95 (33), 110 (39), 127 (26), 170 (0,
[M•+]); isomer 2 43 (100), 55 (21), 67 (43), 81 (81), 95 (37), 110
(43), 127 (23), 170 (0, [M•+]).
Cyclohexene Oxide (3a) [286-20-4]. 1H NMR (300 MHz,
CDCl3) δ 1.1−1.3 (2H, m), 1.4−1.5 (2H, m), 1.7−1.9 (2H, m), 1.9−
2.0 (2H, m), 3.1 (2H, m); 13C NMR (75 MHz, CDCl3) δ 19.4, 24.4,
52.2. EM (EI+, 70 eV): m/z (rel abund) 39 (33), 41 (50), 42 (47), 54
(35), 55 (31), 57 (24), 69 (27), 70 (18), 83 (100), 97 (15), 98 (4,
[M•+]).
1
(Z)-3-Heptene Oxide (3b) [56052-94-9]. H NMR (300 MHz,
CDCl3) δ 1.0−1.2 (m, 6H), 1.4−1.7 (m, 6H), 2.8−3.0 (2H, m); 13C
NMR (75 MHz, CDCl3) δ 10.5, 14.0, 19,8, 21.0, 29.6, 57.3, 58.5. EM
(EI+, 70 eV): m/z (rel abund) 57 (100), 67 (14), 72 (87), 81 (3), 85
(41), 99 (13), 114 (1, [M•+]).
1
(E)-3-Heptene Oxide (3c) [56052-95-0]. H NMR (300 MHz,
CDCl3) δ 0.92 (3H, dt, J1 = 2,6 Hz, J2 = unresolved), 0.95 (3H, t, J =
7.5 Hz), 1.3−1.6 (6H, m), 2.6−2.7 (2H, m); 13C NMR (75 MHz,
CDCl3) δ 9.8, 13.8, 19,3, 25.1, 34.0, 58.5, 60.0. EM (EI+, 70 eV): m/z
(rel abund) 57 (100), 67 (14), 72 (90), 81 (4), 85 (37), 99 (14), 114
(1, [M•+]).
exo-Norbornene Oxide (3d) [3146-39-2]. 1H NMR (300 MHz,
CDCl3) δ 0.7 (1H, d), 1.1−1.2 (2H, m), 1.3 (1H, m), 1.4 (2H, m), 2.4
(2H, s), 3.1 (2H, s); 13C NMR (75 MHz, CDCl3) δ 25.0, 26.2, 36.6,
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dx.doi.org/10.1021/jo300533b | J. Org. Chem. 2012, 77, 6409−6413