9692
C.-K. Lin, T.-J. Lu / Tetrahedron 66 (2010) 9688e9693
listed. Melting points were measured on a Mel-Temp II with a cap-
illary melting point tube. Thin-layer chromatography (TLC) plates
visualized by exposure to ultraviolet light at 254 nm and/or im-
mersion in a staining solution (phosphomolybdic acid) followed by
heating on a hot plate. Flash chromatography was carried out uti-
lizing silica gel 60, 70e230 mesh ASTM. All reagents and solvents are
commercially available and were used without further purification.
IBX was prepared according to the literature procedure.36
(400 MHz): d C
9.98 (s, 1H), 7.93e7.89 (m, 2H), 7.25e7.20 (m, 2H); 13
NMR (100 MHz): d 189.9, 167.4, 164.8, 132.4, 132.1, 116.0, 115.5; MS:
m/z 124 (Mþ, 69.1),123 (100.0), 95 (73.8), 75 (43.0); HRMS m/z calcd
for C7H5FO Mþ 124.0324, found Mþ 124.0319.
4.2.8. 2-Chlorobenzaldehyde. Yield: 134 mg (95%). Colorless oil. IR
(KBr, neat): 3069 (w), 2849 (w), 2761 (w), 1697 (s) cmꢁ1 1H NMR
;
(400 MHz):
d
10.43 (s, 1H), 7.86 (td, J¼8.0, 1.6 Hz, 1H), 7.52e7.35 (m,
3H); 13C NMR (100 MHz):
d
189.8, 137.7, 135.2, 132.2, 130.3, 129.5,
4.2. General procedure
127.3; MS: m/z 140 (Mþ, 69.0), 139 (100.0), 111 (56.3), 75 (43.9), 50
(35.3); HRMS m/z calcd for C7H5ClO Mþ 140.0029, found Mþ
140.0031.
A suspension of the alcohol (1 mmol), IBX (1.2 mmol), and acetic
acid (1.2 mmol) in acetonitrile (5 mL) was stirred vigorously at room
temperature. The reaction progress was monitored by TLC plate or
1H NMR. After completion of the reaction, sodium bicarbonate
(100 mg) was added to the mixture. The resulting mixture was
passed through a short path of silica gel using ethyl acetate as the
eluent. After removal of the solvent, desired aldehyde was obtained.
4.2.9. 4-Chlorobenzaldehyde. Yield: 136 mg (97%). White solid.
Mp¼43e46 ꢀC; IR (KBr, CHCl3): 3056 (m), 2833 (ms), 2727 (ms),
1709 (s) cmꢁ1; 1H NMR (400 MHz):
d
9.96 (s, 1H), 7.82 (d, J¼8.0 Hz,
2H), 7.48 (d, J¼8.0 Hz, 2H); 13C NMR (100 MHz):
d 190.7, 141.1, 134.9,
131.0, 129.4; MS: m/z 140 (Mþ, 83.3), 139 (100.0), 111 (57.6), 75
(77.1), 50 (39.1); HRMS m/z calcd C7H5ClO for Mþ 140.0029, found
4.2.1. Benzaldehyde. Yield: 100 mg (94%). Colorless oil. IR (KBr,
M
þ 140.0026.
neat): 3073 (m), 2827 (m), 2745 (m), 1696 (s) cmꢁ1 1H NMR
;
(400 MHz):
d
10.01 (s, 1H), 7.75e7.79 (m, 2H), 7.60e7.42 (m, 3H);
4.2.10. 2-Bromobenzaldehyde. Yield: 172 mg (93%). Colorless oil. IR
(KBr, neat): 3019 (m), 2862 (m), 2757 (m), 1698 (s) cmꢁ1 1H NMR
(400 MHz): 10.23 (s, 1H), 7.86e7.79 (m, 1H), 7.56e7.49 (m, 1H),
13C NMR (100 MHz):
d
192.2, 136.2, 134.1, 129.8, 128.7; MS: m/z 106
;
(Mþ, 62.8), 105 (91.9), 91 (44.7), 77 (100.0); HRMS m/z calcd C7H6O
d
for Mþ 106.0419, found Mþ 106.0422.
7.33e7.28 (m, 2H); 13C NMR (100 MHz):
d 191.3, 135.3, 133.6, 133.2,
130.1, 127.9, 126.8; MS: m/z 184 (Mþ, 60.1), 183 (100.0), 155 (39.2),
75 (48.8), 50 (67.6); HRMS m/z calcd for C7H5BrO Mþ 183.9524,
found Mþ 183.9531.
4.2.2. 2-Methoxybenzaldehyde. Yield: 129 mg (95%). White solid.
Mp¼36e41 ꢀC; IR (KBr, CHCl3): 3011 (m), 2843 (m), 2758 (m), 1690
(s) cmꢁ1; 1H NMR (400 MHz):
d
10.48 (s, 1H), 7.82 (dd, J¼8.0, 1.6 Hz,
1H), 7.54 (td, J¼8.0, 1.6 Hz, 1H), 7.02e6.98 (m, 2H), 3.90 (s, 3H); 13C
4.2.11. 4-Bromobenzaldehyde. Yield: 176 mg (95%). White solid.
Mp¼56e58 ꢀC; IR (KBr, CHCl3): 3077 (w), 2820 (m), 2766 (m), 1694
NMR (100 MHz): d 188.9, 161.3, 136.0, 128.4, 124.6,120.5, 111.4, 55.7;
MS: m/z 136 (Mþ, 100.0), 135 (55.6), 77 (84.9); HRMS m/z calcd
(s) cmꢁ1; 1H NMR (400 MHz):
d
9.99 (s, 1H), 7.74 (d, J¼8.4 Hz, 2H),
C8H8O2 for Mþ 136.0524, found Mþ 136.0531.
7.68 (d, J¼8.4 Hz, 2H); 13C NMR (100 MHz):
d 191.2, 135.2, 132.3,
130.8, 129.7; MS: m/z 184 (Mþ, 81.9), 185 (100.0), 183 (94.7), 155
(48.1), 76 (41.5), 50 (56.1); HRMS m/z calcd for C7H5BrO Mþ
183.9524, found Mþ 183.9527.
4.2.3. 4-Methoxybenzaldehyde. Yield: 129 mg (95%). Colorless oil.
IR (KBr, neat): 3011 (w), 2826 (w), 2738 (w), 1700 (s) cmꢁ1; 1H NMR
(400 MHz):
d
9.81 (s, 1H), 7.76 (d, J¼8.8 Hz, 2H), 7.02 (d, J¼8.8 Hz,
2H), 3.80 (s, 3H); 13C NMR (100 MHz):
d
190.5, 164.4, 131.6, 129.8,
4.2.12. 2-Nitrobenzaldehyde. Yield: 145 mg (96%). Pale yellow solid.
Mp¼40e43 ꢀC; IR (KBr, CHCl3): 3061 (w), 2860 (w), 2749 (w), 1700
114.0, 55.5; MS: m/z 136 (Mþ, 68.0), 135 (100.0), 77 (38.9); HRMS
m/z calcd for C8H8O2 Mþ 136.0524, found Mþ 136.0517.
(s), 1532 (s), 1344 (s) cmꢁ1 1H NMR (400 MHz):
; d 10.42 (s, 1H),
8.12e7.78 (m, 5H); 13C NMR (100 MHz):
d 188.2, 149.6, 134.2, 133.8,
4.2.4. 2-Methylbenzaldehyde. Yield: 114 mg (95%). Colorless oil. IR
131.4, 129.7, 124.5; MS: m/z 151 (Mþ, 0.27), 121 (77.9), 93 (50.0), 76
(69.4), 65 (100.0), 51 (83.1); HRMS m/z calcd for C7H5NO3 Mþ
151.0629, found Mþ 151.0272.
(KBr, neat): 3030 (w), 2850 (w), 2733 (w), 1698 (s) cmꢁ1 1H NMR
;
(400 MHz):
d
10.29 (s, 1H), 7.80 (d, J¼4.4 Hz, 1H), 7.49e7.44 (m, 1H),
7.37e7.32 (m, 1H), 7.28 (d, J¼4.4 Hz, 1H), 2.66 (s, 3H); 13C NMR
(100 MHz):
d
192.8, 140.3, 133.9, 133.5, 131.9, 131.6, 126.2, 20.1; MS:
4.2.13. 4-Nitrobenzaldehyde. Yield: 145 mg (96%). Pale yellow solid.
Mp¼105e106 ꢀC; IR (KBr, CHCl3): 3070 (w), 2850 (ms), 2733 (w),
m/z 120 (Mþ, 40.3), 119 (48.8), 91 (100.0), 65 (27.4); HRMS m/z calcd
for C8H8O Mþ 120.0575, found Mþ 120.0570.
1703 (s), 1549 (m), 1345 (m) cmꢁ1 1H NMR (400 MHz):
; d 10.16 (s,
1H), 8.37 (d, J¼8.8 Hz, 2H), 8.05 (d, J¼8.8 Hz, 2H); 13C NMR
4.2.5. 4-Methylbenzaldehyde. Yield: 114 mg (95%). Colorless oil. IR
(100 MHz): d
190.1, 151.2, 140.0, 130.4, 124.0; MS: m/z 151 (Mþ,
(KBr, neat): 3040 (m), 2825 (m), 2736 (m), 1700 (s) cmꢁ1; 1H NMR
0.35), 121 (79.1), 93 (49.9), 76 (71.6), 65 (100.0), 51 (79.9); HRMS m/
(400 MHz):
d
9.96 (s, 1H), 7.75 (d, J¼8.0 Hz, 2H), 7.30 (d, J¼8.0 Hz,
z calcd for C7H5NO3 Mþ 151.0629, found Mþ 151.0271.
2H), 2.42 (s, 3H); 13C NMR (100 MHz):
d 192.0, 145.4, 134.0, 129.8,
129.7, 21.8; MS: m/z 120 (Mþ, 80.9), 119 (100.0), 91 (61.1), 65 (52.0);
HRMS m/z calcd for C8H8O Mþ 120.0575, found Mþ 120.0567.
4.2.14. Piperonal. Yield: 146 mg (97%). White solid. Mp¼35e37 ꢀC;
IR (KBr, CHCl3): 3078 (w), 2843 (w), 2740 (w), 1688 (s) cmꢁ1 1H
;
NMR (400 MHz):
d
9.73 (s, 1H), 7.36 (dd, J¼8.0, 1.6 Hz, 1H), 7.25 (d,
4.2.6. 2-Fluorobenzaldehyde. Yield: 115 mg (93%). Colorless oil. IR
J¼1.6 Hz, 1H), 6.88 (d, J¼8.0 Hz, 1H), 6.09 (s, 2H); 13C NMR
(KBr, neat): 3069 (m), 2858 (m), 2763 (m), 1699 (s) cmꢁ1; 1H NMR
(100 MHz): d 190.0, 153.1, 148.4, 131.8, 128.5, 108.2, 107.0, 102.1; MS:
(400 MHz):
d
10.35 (s, 1H), 7.89e7.82 (m, 1H), 7.77e7.61 (m, 1H),
m/z 150 (Mþ, 95.1), 149 (100.0), 121 (39.6), 63 (44.5); HRMS m/z
7.27e7.17 (m, 2H); 13C NMR (100 MHz):
d
187.3, 169.9, 136.7, 128.8,
calcd for C8H6O3 Mþ 150.0317, found Mþ 150.0325.
124.6,124.4, 117.0; MS: m/z 124 (Mþ, 24.5), 123 (100.0), 95 (32.6), 75
(26.2); HRMS m/z calcd for C7H5FO Mþ 124.0324, found Mþ
124.0322.
4.2.15. (S)-(ꢁ)-Perillaldehyde. Yield: 135 mg (90%). Colorless oil.
[a
]
23 ꢁ112 (c 1.00, CHCl3); IR (KBr, neat): 3081 (w), 2932 (ms), 2843
D
(w), 2720 (w), 1690 (s) cmꢁ1
;
1H NMR (400 MHz):
d
9.46 (s, 1H),
4.2.7. 4-Fluorobenzaldehyde. Yield: 114 mg (92%). Colorless oil. IR
6.86e6.84 (m,1H), 4.78e4.74 (m, 2H), 2.50e2.44 (m, 2H), 2.31e2.15
(KBr, neat): 3071 (w), 2827 (w), 2742 (w), 1701 (s) cmꢁ1 1H NMR
;
(m, 3H), 1.97e1.90 (m, 1H), 1.79 (s, 3H), 1.57e1.37 (m, 1H); 13C NMR