Enantioselective Fluorination of 2-Oxindoles
H), 7.78 (d, J = 8.8 Hz, 4 H) ppm. 19F NMR (CDCl3, 376 MHz):
δ = –37.10 (s, 1 F) ppm.[8]
J = 23.0 Hz), 35.61, 30.94 ppm. HRMS (EI): calcd. for
C16H17F2NO4S2 389.0567; found 389.0567.
Benzenesulfonamide Derivative 1g: White solid, m.p. 125.7–
Benzenesulfonamide Derivative 1k: A mixture of benzenesulfon-
127.1 °C. IR (KBr): ν = 3107, 1597, 1583, 1477, 1454, 1400, 1385, amide 6a (0.875 g, 5 mmol), sodium hydroxide (0.22 g, 5.5 mmol),
˜
1272, 1239, 1188, 1070, 833.6, 766 cm–1. 1H NMR (CDCl3,
400 MHz): δ = 7.97–8.01 (m, 2 H), 7.76–7.80 (m, 2 H), 7.36–7.39 0.5 h, and then it was cooled to 0 °C. p-nitrobenzene sulfonyl chlor-
(m, 2 H), 7.29–7.33 (m, 2 H) ppm. 19F NMR (CDCl3, 376 MHz):
ide (5c; 1.22 g, 5.5 mmol) was added, and the mixure was stirred
δ = –37.639 (m, 1 F), –103.282 (m, 2 F) ppm. 13C NMR (CDCl3, until TLC indicated the disappearance of compound 6b. The mix-
and MeOH (10 mL) in a 50 mL three-necked flask was stirred for
100 MHz): δ = 160.26 (d, J = 262 Hz), 138.80 (d, J = 9 Hz), 132.63,
124.90 (d, J = 4 Hz), 122.83 (d, J = 12 Hz), 118.07 (d, J = 21 Hz)
ture was filtered, and the insoluble solid was collected to give 1k
(1.24 g, 69%) as white crystals, m.p. 148.5.1–152.6. IR (KBr): ν =
˜
ppm. HRMS (EI): calcd. for C12H8F3NO4S2 350.9847; found 3105, 3070, 3037, 1606, 1538, 1454, 1383, 1347, 1311, 1196, 1175,
350.9849.
860, 738 cm–1. 1H NMR (400 MHz, CDCl3): δ = 8.44 (d, J = 9 Hz,
2 H), 8.23 (d, J = 8.9 Hz, 2 H), 8.01 (d, J = 7.5 Hz, 2 H), 7.80 (t, J
= 7.5 Hz, 1 H), 7.63 (t, J = 7.9 Hz, 2 H) ppm. 19F NMR (367 MHz,
CDCl3): δ = –36.06 (s, 1 F) ppm. 13C NMR (100 MHz, CDCl3): δ =
151.84, 140.04, 136.35, 134.33, 131.35, 129.86, 129.72, 124.59 ppm.
HRMS (EI): calcd. for C12H9FN2O6S2 359.9886; found 359.9886.
N,4-Difluoro-N-[(4-nitrophenyl)sulfonyl]benzenesulfonamide
(1h).
Method B: A mixture of benzenesulfonamide 6b (0.965 g, 5 mmol),
sodium hydroxide (0.22 g, 5.5 mmol), and MeOH (10 mL) in a
50 mL three-necked flask was stirred for 0.5 h, and then it was
cooled to 0 °C. 4-Nitrobenzenesulfonyl chloride (5c; 1.22 g,
5.5 mmol) was added, and the mixture was stirred until TLC indi-
cated the disappearance of compound 6b. The mixture was filtered,
and the insoluble solid was collected to give 1h (1.24 g, 66%) as
Benzenesulfonamide Derivative 1l: A mixture of benzenesulfon-
amide 6a (0.875 g, 5 mmol), sodium hydroxide (0.22 g, 5.5 mmol),
and MeOH (10 mL) in a 50 mL three-necked flask was stirred for
0.5 h, and then it was cooled to 0 °C. 2-Fluorobenzenesulfonyl
white crystals, m.p. 138.7–138.9. IR (KBr): ν = 3110, 3069, 1587,
˜
1535, 1409, 1187, 1080, 845, 789 cm–1. 1H NMR (400 MHz, chloride (5e; 1.07 g, 5.5 mmol) was added, and the mixure was
CDCl3): δ = 8.47 (d, J = 8.8 Hz, 2 H), 8.26 (d, J = 8.8 Hz, 2 H),
8.09–8.07 (m, 2 H), 7.36–7.30 (m, 2 H) ppm. 19F NMR (367 MHz,
CDCl3): δ = –36.19 (s, 1 F), –98.10 (s, 1 F) ppm. 13C NMR
stirred until TLC indicated the disappearance of compound 6a.
The mixture was filtered, and the insoluble solid was collected to
give 1l (0.754 g, 45%) as white crystals, m.p. 100.8–101.6. IR (KBr):
(100 MHz, CDCl3): δ = 167.42 (d, J = 261.6 Hz), 151.90, 139.98, ν = 3107, 1597, 1581, 1478, 1452, 1398, 1272, 1189, 1071, 831, 794,
˜
133.12 (d, J = 10.4 Hz), 131.36, 130.20 (d, J = 3.1 Hz), 124.73,
117.33 (d, 23.1 Hz) ppm. HRMS (EI): calcd. for
C12H8F2N2O6S2 377.9792; found 377.9794.
707 cm–1. 1H NMR (300 MHz, CDCl3): δ = 8.13–8.05 (m, 2 H),
8.01–7.93 (m, 1 H), 7.84–7.76 (m, 2 H), 7.65 (t, J = 7.8 Hz, 2 H),
7.43–7.30 (m, 2 H) ppm. 19F NMR (282 MHz, CDCl3): δ = –37.13
(d, J = 11.5 Hz, 1 F), –103.35 (d, J = 11.3 Hz, 1 F) ppm. 13C NMR
(75 MHz, CDCl3): δ = 160.18 (d, J = 265.1 Hz), 138.56 (d, J =
8.9 Hz), 136.04, 134.53, 132.48, 129.97, 129.54, 124.82 (d, J =
4.0 Hz), 122.98 (d, J = 12.8 Hz), 118.03 (d, J = 20.8 Hz) ppm.
HRMS (EI): calcd. for C12H9F2NO4S2 332.9941; found 332.9942.
J
=
Benzenesulfonamide Derivative 1i: A mixture of benzenesulfon-
amide 6b (0.965 g, 5 mmol), sodium hydroxide (0.22 g, 5.5 mmol),
and MeOH (10 mL) in a 50 mL three-necked flask was stirred for
0.5 h, and then it was cooled to 0 °C. 2-Fluorobenzenesulfonyl
chloride (5e; 1.07 g, 5.5 mmol) was added, and the mixture was
stirred until TLC indicated the disappearance of compound 6b. The
mixture was filtered, and the insoluble solid was collected to give
Benzenesulfonamide Derivative 1m: A mixture of benzenesulfon-
amide 6a (0.875 g, 5 mmol), sodium hydroxide (0.22 g, 5.5 mmol),
and MeOH (10 mL) in a 50 mL three-necked flask was stirred for
0.5 h, and then it was cooled to 0 °C. 3-Fluorobenzenesulfonyl
1i (1.20 g, 72%) as white crystals, m.p. 107.7–107.8. IR (KBr): ν =
˜
1
3017, 3064, 1586, 1478, 1403, 1194, 1158, 832, 699 cm–1. H NMR
(300 MHz, CDCl3): δ = 8.14–8.09 (m, 2 H), 8.00–7.94 (m, 1 H), chloride 5d (1.07 g, 5.5 mmol) was added, and the mixure was
7.85–7.77 (m, 1 H), 7.42–7.30 (m, 4 H) ppm. 19F NMR (367 MHz,
stirred until TLC indicated the disappearance of compound 6a.
CDCl3): δ = –36.70 (d, J = 11.1 Hz, 1 F), –98.33 (s, 1 F), –103.35 The mixture was filtered, and the insoluble solid was collected to
(d, J = 10.8 Hz, 1 F) ppm. 13C NMR (75 MHz, CDCl3): δ = 167.27
(d, J = 260.8 Hz), 160.18 (d, J = 265.3 Hz), 138.71 (d, J = 9.0 Hz),
give 1m (0.956 g, 57%) as white crystals, m.p. 113.0–113.8. IR
(KBr): ν = 3101, 1594, 1476, 1450, 1403, 1389, 1314, 1231, 1198,
˜
1
133.18 (d, J = 10.3 Hz), 132.45, 130.39 (d, J = 3.2 Hz), 124.88 (d, 1177, 1085, 892, 820, 727 cm–1. H NMR (300 MHz, CDCl3): δ =
J = 4.0 Hz), 122.86 (d, J = 12.7 Hz), 118.07 (d, J = 20.8 Hz), 117.11
(d, J = 23.1 Hz) ppm. HRMS (EI): calcd. for C12H8F3NO4S2
350.9847; found 350.9847.
8.09–8.01 (m, 2 H), 7.89–7.77 (m, 2 H), 7.76–7.70 (m, 1 H), 7.69–
7.58 (m, 3 H), 7.55–7.44 (m, 1 H) ppm. 19F NMR (367 MHz,
CDCl3): δ = –36.72 (s, 1 F), –108.04 (s, 1 F) ppm. 13C NMR
(100 MHz, CDCl3): δ = 162.20 (d, J = 253.6 Hz), 136.28 (d, J =
7.4 Hz), 136.10, 134.46, 131.37 (d, J = 7.7 Hz), 129.84, 129.59,
125.74 (d, J = 3.5 Hz), 123.29 (d, J = 21.1 Hz), 117.09 (d, J =
25.3 Hz) ppm. HRMS (EI): calcd. for C12H9F2NO4S2 332.9941;
found 332.9940.
Benzenesulfonamide Derivative 1j: A mixture of benzenesulfon-
amide 6b (0.965 g, 5 mmol), sodium hydroxide (0.22 g, 5.5 mmol),
and MeOH (10 mL) in a 50 mL three-necked flask was stirred for
0.5 h, and then it was cooled to 0 °C. 4-tert-butylbenzenesulfonyl
chloride (5a; 1.28 g, 5.5 mmol) was added, and the mixture was
stirred until TLC indicated the disappearance of compound 6b. The
mixture was filtered, and the insoluble solid was collected to give
Benzenesulfonamide Derivative 1n: A mixture of benzenesulfon-
amide 6a (0.875 g, 5 mmol), sodium hydroxide (0.22 g, 5.5 mmol),
and MeOH (10 mL) in a 50 mL three-necked flask was stirred for
0.5 h, and then it was cooled to 0 °C. 2-Methylbenzenesulfonyl
1j (1.16 g, 60%) as white crystals, m.p. 97.2–98.7. IR (KBr): ν =
˜
3111, 3970, 2874, 1591, 1491, 1404, 1387, 1198, 1081, 841,
817 cm–1. 1H NMR (300 MHz, CDCl3): δ = 8.15–8.01 (m, 2 H), chloride (5f; 1.05 g, 5.5 mmol) was added, and the mixure was
7.92 (d, J = 8.7 Hz, 2 H), 7.62 (d, J = 8.7 Hz, 2 H), 7.30–7.26 (d,
J = 8.7 Hz, 2 H), 1.38 (s, 9 H) ppm. 19F NMR (367 MHz, CDCl3):
δ = –36.46 (s, 1 F), –98.31 (m, 1 F) ppm. 13C NMR (100 MHz,
CDCl3): δ = 167.09 (d, J = 260.3 Hz), 160.52, 133.04 (d, J =
10.4 Hz), 131.27, 130.50 (d, J = 3.1 Hz), 129.74, 126.61, 116.97 (d,
stirred until TLC indicated the disappearance of compound 6a.
The mixture was filtered, and the insoluble solid was collected to
give 1n (0.926 g, 56%) as white crystals, m.p. 116.1–116.9. IR
(KBr): ν = 3098, 3064, 1583, 1455, 1397, 1376, 1312, 1192, 1182,
˜
1
795, 760, 726 cm–1. H NMR (300 MHz, CDCl3): δ = 8.12 (d, J =
Eur. J. Org. Chem. 2014, 3607–3613
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3611