3. Materials and Methods
The reactions were conducted in flame-dried glassware, under the nitrogen atmosphere. Acetonitrile and dichloromethane were purified and dried from a safe purification system containing activated Al2O3. All reagents obtained from commercial sources were used without purification unless otherwise mentioned. Flash column chromatography was carried out on Silica Gel 60. TLC was performed on pre-coated glass plates of Silica Gel 60 F254 detection was executed by spraying with a solution of Ce(NH4)2(NO3)6 (0.5 g), (NH4)6Mo7O24 (24.0 g), and H2SO4 (28.0 mL) in water (500.0 mL) and subsequent heating on a hot plate. Optical rotations were measured at 589 nm (Na), 1H, 13C NMR, DEPT, 1H-1H COSY, 1H-13C COSY, and NOESY spectra were recorded with 400 MHz instruments. Chemical shifts are in ppm from Me4Si generated from the CDCl3 lock signal at δ 7.26. IR spectra were taken with a FT-IR spectrometer using NaCl plates. Mass spectra were analyzed on instrument with an EI, ESI, APCI, and FAB source.
(4-Methoxyphenyl)-phenylmethanone (
4a). To a solution of aryl alkane
2a (217 μL, 2 mmol), acyl chloride
3a (116 μL, 1 mmol), and ionic liquid
1d (349 mg, 0.9 mmol) were stirred at 100 °C for two hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO
3, and brine, and dried over MgSO
4. After filtration, the organic solvent was then removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4a (165 mg, 78%) as a light yellow oil. R
f 0.37 (EtOAc/Hex = 1/6). IR (NaCl) v 3060, 3006, 2840, 1651, 1597, 1508, 1171 cm
−1;
1H NMR (
Supplementary Materials) (400 MHz, CDCl
3) δ 7.82 (d,
J = 8.8 Hz, 2H), 7.74 (d,
J = 6.8 Hz, 2H), 7.55 (t,
J = 7.4 Hz, 1H), 7.45 (t,
J = 7.6 Hz, 2H), 6.95 (d,
J = 9.2 Hz, 2H), 3.86 (s, 3H);
13C NMR (101 MHz, CDCl
3) δ 195.4, 163.1, 138.2, 132.4, 131.8, 130.0, 129.6, 128.1, 113.4, 55.4; HRMS (EI, M
+) calculated for C
14H
12O
2 212.0837, found 212.0834.
(2-Chlorophenyl)-(4-methoxyphenyl) methanone (4b). To a solution of aryl alkane 2a (217 μL, 2 mmol), acyl chloride 3b (126 μL, 1 mmol), and ionic liquid 1d (349 mg, 0.9 mmol) were stirred at 100 °C for four hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO3, and brine, and dried over MgSO4. After filtration, the organic solvent was removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4b (180 mg, 73%) as a light yellow solid. Rf 0.40 (EtOAc/Hex = 1/4); mp 71–74 °C; IR (NaCl) v 3068, 3009, 2964, 2840, 1659, 1595, 1508, 1464, 1149, 843 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.79 (d, J = 9.2 Hz, 2H), 7.47–7.38 (m, 2H), 7.37–7.36 (m, 1H), 7.35 (d, J = 1.2 Hz, 1H), 6.94 (d, J = 9.2 Hz, 2H), 3.88 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 193.8, 164.1, 139.0, 132.5, 131.0, 130.8, 129.9, 129.4, 128.8, 126.6, 113.8, 55.5; HRMS (ESI, M + H+) calculated for C14H12ClO2 247.0526, found 247.0525
(4-Chlorophenyl)-(4-methoxyphenyl)methanone (4c). To a solution of aryl alkane 2a (217 μL, 2 mmol), acyl chloride 3c (127 μL, 1 mmol), and ionic liquid 1d (349 mg, 0.9 mmol) were stirred at 100 °C for four hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO3, and brine, and dried over MgSO4. After filtration, the organic solvent was removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4c (168 mg, 68%) as a light yellow solid. Rf 0.37 (EtOAc/Hex = 1/4); mp 119–122 °C; IR (NaCl) v 2962, 2934, 2841, 1641, 1604, 1509, 1461, 1148, 760 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.80 (d, J = 8.4 Hz, 2H), 7.71 (d, J = 8.4 Hz, 2H), 7.45 (d, J = 8.4 Hz, 2H), 6.97 (d, J = 8.8 Hz, 2H), 3.89 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 194.2, 163.3, 138.2, 136.5, 132.4, 131.1, 129.7, 128.5, 113.6, 55.5; HRMS (ESI, M + H+) calculated for C14H12ClO2 247.0526, found 247.0523.
(2,4,6-Trimethylphenyl)-phenylmethanone (4d). To a solution of aryl alkane 2b (278 µL, 2 mmol), acyl chloride 3a (116 µL, 1 mmol) and ionic liquid 5 (349 mg, 0.9 mmol) were stirred at 100 °C for 2 hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO3, and brine, and dried over MgSO4. After filtration, the organic solvent was then removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4d (186 mg, 83%) as a light yellow oil. Rf 0.40 (EtOAc/Hex = 1/12); IR (NaCl) v 3061, 2951, 2921, 2860, 1671, 1449, 1380 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.81 (d, J = 7.2 Hz, 2H), 7.57 (t, J = 7.2 Hz, 1H), 7.44 (t, J = 7.8 Hz, 2H), 6.90 (s, 2H), 2.34 (s, 3H), 2.09 (s, 6H); 13C NMR (101 MHz, CDCl3) δ 200.8, 138.5, 137.3, 136.8, 134.1, 133.5, 129.4, 128.7, 128.3, 21.1, 19.3; HRMS (ESI, M + H+) calculated for C16H17O 225.1279, found 225.1281.
(2-Chlorophenyl)-(2,4,6-trimethylphenyl) methanone (4e). To a solution of aryl alkane 2b (278 μL, 2 mmol), acyl chloride 3b (126 μL, 1 mmol), and ionic liquid 1d (349 mg, 0.9 mmol) were stirred at 100 °C for 3.5 hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO3, and brine, and dried over MgSO4. After filtration, the organic solvent was then removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4e (204 mg, 79%) as a light orange solid. Rf 0.53 (EtOAc/Hex = 1/10). mp 101–102 °C; IR (NaCl) v 2917, 1671, 1610, 1584, 1436 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.47 (d, J = 7.8 Hz, 2H), 7.41 (t, J = 7.7 Hz, 1H), 7.26 (t, J = 7.5 Hz, 1H), 6.87 (s, 2H), 2.31 (s, 3H), 2.12 (s, 6H); 13C NMR (101 MHz, CDCl3) δ 198.9, 139.3, 137.6, 137.3, 135.0, 133.2, 132.7, 131.7, 131.4, 128.8, 126.8, 21.1, 19.7; HRMS (ESI, M + Na+) calculated for C16H15ClONa 281.0709, found 281.0710.
(4-Chlorophenyl)-(2,4,6-trimethylphenyl)methanone (4f). To a solution of aryl alkane 2b (278 μL, 2 mmol), acyl chloride 3c (127 μL, 1 mmol), and ionic liquid 1d (349 mg, 0.9 mmol) were stirred at 100 °C for two hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO3, and brine, and dried over MgSO4. After filtration, the organic solvent was then removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4f (230 mg, 89%) as a white solid. Rf 0.61 (EtOAc/Hex = 1/10). mp 64–65 °C; IR (NaCl) v 2921, 1673, 1586 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.74 (d, J = 8.4 Hz, 2H), 7.41 (d, J = 8.5 Hz, 2H), 6.90 (s, 2H), 2.33 (s, 3H), 2.07 (s, 6H); 13C NMR (101 MHz, CDCl3) δ 199.5, 140.1, 138.7, 136.3, 135.6, 134.1, 130.7, 129.1, 128.4, 21.1, 19.3; HRMS (APCI, M + H+) calculated for C16H16ClO 259.0890, found 259.0888.
(3,4-Dimethoxyphenyl)-phenylmethanone (4g). To a solution of aryl alkane 2c (256 µL, 2 mmol), acyl chloride 3a (116 µL, 1 mmol) and ionic liquid 1d (349 mg, 0.9 mmol) were stirred at 100 °C for three hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO3, and brine, and dried over MgSO4. After filtration, the organic solvent was then removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4g (196 mg, 81%) as a white solid. Rf 0.45 (EtOAc/Hex = 1/4); mp 100–101 °C; IR (NaCl) v 3079, 3003, 2960, 2839, 1649, 1594, 1272, 1130 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.75 (d, J = 8.2 Hz, 2H), 7.55 (t, J = 7.4 Hz, 1H), 7.48 (d, J = 2.0 Hz, 1H), 7.46 (t, J = 7.5 Hz, 2H), 7.36 (dd, J = 8.3, 2.0 Hz, 1H), 6.88 (d, J = 8.4 Hz, 1H), 3.94 (s, 3H), 3.92 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 195.4, 152.9, 148.9, 138.1, 131.7, 130.0, 129.6, 128.0, 125.4, 111.9, 109.6, 55.9; HRMS (ESI, M + Na+) calculated for C15H14O3Na 265.0841, found 265.0844.
(2-Chlorophenyl)-(3,4-dimethoxyphenyl) methanone (4h). To a solution of aryl alkane 2c (256 μL, 2 mmol), acyl chloride 3b (126 μL, 1 mmol), and ionic liquid 1d (349 mg, 0.9 mmol) were stirred at 100 °C for 3.5 hours. After cooling, the reaction mixture was washed by diethyl ether (2 × 40 mL). The diethyl ether layer was decanted, extracted with water, aqueous NaHCO3, and brine, and dried over MgSO4. After filtration, the organic solvent was then removed on a rotary evaporator. The residue was purified by flash chromatography to give the desired product 4h (196 mg, 71%) as a light yellow solid. Rf 0.34 (EtOAc/Hex = 1/2). mp 142–143 °C; IR (NaCl) v 3079, 2936, 2840, 1659, 1592, 1513, 1464, 1418, 1133 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.56 (d, J = 2.0 Hz, 1H), 7.45–7.37 (m, 2H), 7.34 (t, J = 1.0 Hz, 1H), 7.33 (d, J = 1.1 Hz, 1H), 7.19 (dd, J = 8.4, 2.0 Hz, 1H), 6.82 (d, J = 8.4 Hz, 1H), 3.92 (d, J = 1.8 Hz, 6H); 13C NMR (101 MHz, CDCl3) δ 193.8, 153.9, 149.2, 138.8, 131.0, 130.7, 129.9, 129.4, 128.8, 126.5, 126.3, 110.7, 109.9, 56.1, 55.9; HRMS (ESI, M + H+) calculated for C15H14ClO3 277.0631, found 277.0632.
(4-Chlorophenyl)-(3,4-dimethoxyphenyl)methanone (4i). To a solution of aryl alkane 2c (256 µL, 2 mmol), acyl chloride 3c (127 µL, 1 mmol), and ionic liquid 1d (349 mg, 0.9 mmol) were stirred at 100 °C for three hours. After cooling, the reaction mixture was extracted by ethyl acetate (2 × 40 mL). The ethyl acetate layer was decanted, washed with water, aqueous NaHCO3, and brine, and dried over MgSO4. The residue was purified by flash chromatography to give the desired product 4i (193 mg, 70%) as a white solid. Rf 0.28 (EtOAc/Hex = 1/4). mp 113–114 °C; IR (NaCl) v 2935, 2839, 1649, 1594, 1514, 1272 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.72 (d, J = 8.4 Hz, 2H), 7.48–7.46 (m, 2H), 7.45–7.44 (m, 1H), 7.34 (dd, J = 8.0, 2.0 Hz, 1H), 6.90 (d, J = 8.4 Hz, 1H), 3.97 (s, 3H), 3.95 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 193.8, 152.9, 148.8, 137.9, 136.2, 130.9, 129.5, 128.2, 125.1, 111.6, 109.5, 55.8, 55.7; HRMS (ESI, M + H+) calculated for C15H14ClO3 277.0632, found 277.0656.
S-Dodecyl benzothioate (7a). To a solution of thiol 6a (240 µL, 1 mmol), aldehyde 5a (510 µL, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered and concentrated. The residue was purified by flash chromatography to give the desire product 7a (214 mg, 70% yield) as a colorless liquid. Rf 0.36 (Hexane). IR (NaCl) v 3063, 3030, 2925, 2854, 1666, 1597, 1449, 1377, 1027, 1001 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.97 (dd, J = 8.4, 1.2 Hz, 2H), 7.52 (t, J = 7.4 Hz, 1H), 7.41 (t, J = 7.6 Hz, 2H), 3.06 (t, J = 7.4 Hz, 2H), 1.72–1.62 (m, 2H), 1.46–1.38 (m, 2H), 1.27 (s, 16H), 0.89 (t, J = 7.0 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 191.7, 137.1, 133.0, 128.4, 127.0, 31.9, 29.6, 29.5, 29.4, 29.3, 29.1, 28.9, 28.88, 22.6, 14.0; HRMS (FAB, M + H+) calculated for C19H31OS 307.2096, found 307.2087.
S-Decyl benzothioate (7b). To a solution of thiol 6b (212 µL, 1 mmol), aldehyde 5a (510 µL, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for 1 hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered and concentrated. The residue was purified by flash chromatography to give the desire product 7b (245 mg, 88% yield) as a colorless liquid. Rf 0.30 (Hexane). IR (NaCl) v 3063, 3031, 2926, 2854, 1666, 1597, 1449, 1377, 1027, 1001 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.97 (d, J = 7.2 Hz, 2H), 7.53 (t, J = 7.4 Hz, 1H), 7.42 (t, J = 7.8 Hz, 2H), 3.06 (t, J = 7.4 Hz, 2H), 1.63–1.71 (m, 2H), 1.46–1.38 (m, 2H), 1.27 (s, 12H), 0.89 (t, J = 6.8 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 191.9, 137.2, 133.0, 128.4, 127.1, 31.8, 29.5, 29.49, 29.45, 29.2, 29.1, 29.0, 28.9, 22.6, 14.0; HRMS (ESI, M + Na+) calculated for C17H26NaOS 301.1602, found 301.1606.
S-(4-Chlorophenyl) benzothioate (7c). To a solution of thiol 6c (145 mg, 1 mmol), aldehyde 5a (510 µL, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered and concentrated. The residue was purified by flash chromatography to give the desire product 7c (137 mg, 55% yield) as a white solid. Rf 0.25 (Hexane). mp 75–76 °C; IR (NaCl) v 3082, 3055, 1674, 1574, 1474, 1446, 1389, 1203, 1012 cm−1; 1H NMR (400 MHz, CDCl3) δ 8.03 (dd, J = 8.4, 1.2 Hz, 2H), 7.62 (t, J = 7.4 Hz, 1H), 7.50 (t, J = 7.8 Hz, 2H), 7.47–7.41 (m, 4H); 13C NMR (101 MHz, CDCl3) δ 189.5, 136.2, 135.9, 133.8, 129.4, 128.7, 127.4, 125.7; HRMS (ESI, M + Na+) calculated for C13H9ClNaOS 270.9960, found 270.9965.
S-Dodecyl 4-chlorobenzothioate (7d). To a solution of thiol 6a (240 µL, 1 mmol), aldehyde 5b (703 µL, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7d (248 mg, 73%) as a colorless liquid. Rf 0.28 (Hexane). IR (NaCl) v 2925, 2854, 1913, 1825, 1785, 1668, 1589, 1464, 1092 cm1; 1H NMR (400 MHz, CDCl3) δ 7.90 (d, J = 8.8 Hz, 2H), 7.41 (d, J = 8.8 Hz, 2H), 3.07 (t, J = 7.4 Hz, 2H), 1.67 (quint, J = 7.4 Hz, 2H), 1.42 (quint, J = 7.2 Hz, 2H), 1.26 (s, 16H), 0.88 (t, J = 7.0 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 190.9, 139.5, 135.5, 128.8, 128.5, 31.9, 29.6, 29.56, 29.5, 29.3, 29.2, 29.1, 28.9, 22.7, 14.1; HRMS (ESI, M + H+) calculated for C19H30ClOS 341.1706, found 341.1705.
S-Decyl 4-chlorobenzothioate (7e). To a solution of thiol 6b (221 µL, 1 mmol), aldehyde 5b (703 mg, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7e (228 mg, 73%) as a colorless liquid. Rf 0.31 (Hexane). IR (NaCl) v 2955, 2926, 2854, 1668, 1589, 1464, 1092 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.90 (d, J = 8.4 Hz, 2H), 7.41 (d, J = 8.4 Hz, 2H), 3.06 (t, J = 7.2 Hz, 2H), 1.66 (quint, J = 7.4 Hz, 2H), 1.41 (quint, J = 7.2 Hz, 2H), 1.26 (s, 12H), 0.88 (t, J = 6.8 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 191.0, 139.5, 135.6, 128.8, 128.5, 31.9, 29.5, 29.47, 29.3, 29.2, 29.1, 28.9, 22.7, 14.1; HRMS (ESI, M + H+) calculated for C17H26ClOS 313.1393, found 313.1355.
S-Dodecyl 4-methoxybenzothioate (7f). To a solution of thiol 6a (239 μL, 1 mmol), aldehyde 5c (609 μL, 5 mmol), tert-butyl hydroperoxide (276 μL, 2 mmol), and ionic liquid 1d (10 mg, 0.025 mmol) were stirred at 140 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7f (255 mg, 76%) as a colorless liquid. Rf 0.20 (hexane); IR (NaCl) v 2924, 2853, 1658, 1602, 1508, 1463, 1259, 837; 1H NMR (400 MHz, CDCl3) δ 7.93 (d, J = 9.2 Hz, 2H), 6.89 (d, J = 8.8 Hz, 2H), 3.83 (s, 3H), 3.03 (t, J = 7.4 Hz, 2H), 1.68–1.60 (m, 2H), 1.44–1.36 (m, 2H), 1.24 (s, 16H), 0.86 (t, J = 6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 190.4, 163.5, 130.0, 129.2, 113.5, 55.3, 31.9, 29.6, 29.58, 29.54, 29.5, 29.3, 29.1, 28.9, 28.8, 22.6, 14.0; HRMS (ESI, M + Na+) calculated for C20H32NaO2S 359.2020, found 359.2032.
S-Decyl 4-methoxybenzothioate (7g). To a solution of thiol 6b (207 μL, 1 mmol), aldehyde 5c (609 μL, 5 mmol), tert-butyl hydroperoxide (276 μL, 2 mmol), and ionic liquid 1d (10 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7g (226 mg, 73%) as a colorless liquid. Rf 0.25 (hexane); IR (NaCl) v 2925, 2854, 1658, 1602, 1508, 1463, 1259, 838; 1H NMR (400 MHz, CDCl3) δ 7.93 (d, J = 8.8 Hz, 2H), 6.90 (d, J = 8.8 Hz, 2H), 3.84 (s, 3H), 3.02 (t, J = 7.4 Hz, 2H), 1.68–1.60 (m, 2H), 1.44–1.35 (m, 2H), 1.24 (s, 12H), 0.86 (t, J = 6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 190.4, 163.5, 130.0, 129.2, 113.6, 55.3, 31.8, 29.6, 29.5, 29.4, 29.2, 29.1, 28.9, 28.8, 22.6, 14.0; HRMS (ESI, M + Na+) calculated for C18H28NaO2S 331.1708, found 331.1702.
S-(4-Chlorophenyl) 4-methoxybenzothioate (7h). To a solution of thiol 6c (145 mg, 1 mmol), aldehyde 5c (609 μL, 5 mmol), tert-butyl hydroperoxide (276 μL, 2 mmol), and ionic liquid 1d (10 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered and concentrated. The residue was purified by flash chromatography to give the desire product 7h (142 mg, 51%) as a white solid. Rf 0.45 (EtOAc /Hex = 1/4); mp 96–97 °C; IR (NaCl) v 1690, 1660, 1602, 1508, 1261, 833; 1H NMR (400 MHz, CDCl3) δ 7.98 (d, J = 9.2 Hz, 2H), 7.41 (d, J = 3.2 Hz, 4H), 6.94 (d, J = 8.8 Hz, 2H), 3.84 (s, 3H).; 13C NMR (100 MHz, CDCl3) δ 187.7, 164.0, 136.2, 135.6, 129.6, 129.2, 128.9, 126.0, 113.8, 55.4; HRMS (ESI, M + Na+) calculated for C14H11ClNaO2S 301.0066, found 301.0059.
S-Dodecyl hexanethioate (7i). To a solution of thiol 6a (239 μL, 1 mmol), aldehyde 5d (615 μL, 5 mmol), tert-butyl hydroperoxide (276 μL, 2 mmol), and ionic liquid 1d (10 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7i (240 mg, 80%) as a colorless liquid. Rf 0.35 (hexane); IR (NaCl) v 2957, 2926, 2855, 1693, 1464, 1121; 1H NMR (400 MHz, CDCl3) δ 2.85 (t, J = 7.4 Hz, 2H), 2.52 (t, J = 7.6 Hz, 2H), 1.69–1.61 (m, 2H), 1.59–1.51 (m, 2H), 1.37–1.27 (m, 8H), 1.25 (s, 14H), 0.90–0.85 (m, 6H); 13C NMR (100 MHz, CDCl3) δ 199.5, 199.3, 44.0, 31.9, 31.0, 29.6, 29.5, 29.4, 29.3, 29.1, 28.8, 28.7, 25.3, 22.6, 22.3, 14.0, 13.8; HRMS (FAB, M + H+) calculated for C18H37OS 301.2565, found 301.2568.
S-Decyl hexanethioate (7j). To a solution of thiol 6b (221 µL, 1 mmol), aldehyde 5d (615 µL, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7j (194 mg, 71%) as a colorless liquid. Rf 0.40 (Hexane). IR (NaCl) v 2927, 2855, 2731, 2671, 1693, 1463, 1030 cm−1; 1H NMR (400 MHz, CDCl3) δ 2.85 (t, J = 7.4 Hz, 2H), 2.52 (t, J = 7.6 Hz, 2H), 1.65 (quint, J = 7.4 Hz, 2H), 1.55 (quint, J = 7.3 Hz, 2H), 1.30 (m, 8H), 1.25 (s, 10H), 0.88 (q, J = 6.4 Hz, 6H); 13C NMR (101 MHz, CDCl3) δ 199.9, 44.1, 31.9, 31.1, 29.6, 29.5, 29.48, 29.3, 29.1, 28.82, 28.8, 25.4, 22.7, 22.3, 14.1, 13.9; HRMS (ESI, M + Na+) calculated for C16H32NaOS 295.2072, found 295.2072.
S-Dodecyl octanethioate (7k). To a solution of thiol 6a (240 µL, 1 mmol), aldehyde 5e (781 µL, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7k (223 mg, 68% yield) as a colorless liquid. Rf 0.48 (Hexane). IR (NaCl) v 2923, 2855, 1694, 1463, 1377, 1043 cm−1; 1H NMR (400 MHz, CDCl3) δ 2.83 (t, J = 7.2 Hz, 2H), 2.50 (t, J = 7.4 Hz, 2H), 1.69–1.58 (m, 2H), 1.58–1.48 (m, 2H), 1.23 (s, 26H), 0.85 (t, J = 6.6 Hz, 6H); 13C NMR (101 MHz, CDCl3) δ 199.6, 44.1, 31.9, 31.6, 29.6, 29.58, 29.55, 29.5, 29.3, 29.1, 28.9, 28.88, 28.8, 28.7, 25.7, 22.7, 22.6, 14.1, 14.0; HRMS (FAB, M + H+) calculated for C20H41OS 329.2878, found 329.2878.
S-Decyl octanethioate (7l). To a solution of thiol 6b (221 µL, 1 mmol), aldehyde 5e (781 µL, 5 mmol), tert-butyl hydroperoxide (277 µL, 2 mmol), and ionic liquid 1d (9.7 mg, 0.025 mmol) were stirred at 120 °C for one hour in a sealed tube. After cooling, the reaction mixture was extracted with ethyl acetate (3 × 20 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by flash chromatography to give the desire product 7l (192 mg, 64%) as a colorless liquid. Rf 0.35 (Hexane). IR (NaCl) v 2956, 2926, 2855, 2730, 2671, 1693, 1464, 1124 cm−1; 1H NMR (400 MHz, CDCl3) δ 2.85 (t, J = 7.2 Hz, 2H), 2.52 (t, J = 7.4 Hz, 2H), 1.64 (quint, J = 7.2 Hz, 2H), 1.55 (quint, J = 7.3 Hz, 2H), 1.36–1.26 (m, 10H), 1.25 (s, 12H), 0.87 (t, J = 7.0 Hz, 6H); 13C NMR (101 MHz, CDCl3) δ 199.8, 44.1, 31.9, 31.6, 29.6, 29.5, 29.48, 29.3, 29.1, 28.9, 28.8, 28.79, 25.7, 22.7, 22.6, 14.1, 14.0; HRMS (ESI, M + Na+) calculated for C18H36NaOS 323.2385, found 323.2373.