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The Journal of Organic Chemistry
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residue was purified by column chromatography on silica gel to gave the pure compound 10b. Similarly,
compound 10a was prepared.
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1-Benzyl-3a-methoxy-1,2,3,3a-tetrahydro-6H-indol-6-one (10a): 31 mg, 60% yield; Rf = 0.32 (60:40
= EtOAc/n-Hexane); Brown coloured semi solid; FT-IR (neat): 2929, 2364, 2340, 1640, 1559, 1295,
1247, 1083, 1050, 828 cm-1; 1H NMR (400 MHz, CDCl3): δ, 7.38-7.26 (m, 3H), 7.18 (d, J = 6.8 Hz,
2H), 6.42-6.24 (m, 2H), 5.39 (s, 1H), 4.46 (d, J = 15.5 Hz, 1H), 4.34 (d, J = 15.5 Hz, 1H), 3.87 (td, J =
9.6, 5.2 Hz, 1H), 3.30 (dd, J = 9.8, 8.2 Hz, 1H), 3.09 (s, 3H), 2.23 (dd, J = 12.6, 5.1 Hz, 1H), 2.05-1.99
(m, 1H); 13C NMR (100 MHz, CDCl3): δ, 185.4, 164.2, 135.5, 134.4, 134.2, 129.0, 128.0, 127.3, 93.8,
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78.7, 51.5, 51.1, 49.9, 35.4; DEPT-135 C NMR (100 MHz, CDCl3): δ, 134.4, 134.2, 129.0, 128.0,
127.3, 93.8, 51.5, 51.1, 49.9, 35.4; HR-MS (ESI, m/z): [M+H]+ calculated for C16H18NO2: 256.1332;
found: 256.1338.
3a-Methoxy-1-((S)-1-phenylethyl)-1,2,3,3a-tetrahydro-6H-indol-6-one (10b): (dr 1.8:1) 16 mg, 30%
yield; Rf = 0.18 (30:70 = EtOAc/n-Hexane); Dark green colored semi solid; FT-IR (neat): 2922, 2847,
2360, 2334, 1643, 1358, 1248, 1261, 1207, 1157, 1083, 831 cm-1; Major Diastereomer: 1H NMR (400
MHz, CDCl3): δ, 7.36-7.30 (m, 2H), 7.30-7.25 (m, 1H), 7.20 (d, J = 7.3 Hz, 2H), 6.31 (d, J = 2.5 Hz,
2H), 5.42 (s, 1H), 4.98-4.86 (m, 1H), 3.75 (td, J = 9.6, 5.0 Hz, 1H), 3.19-3.13 (m, 1H), 3.11 (s, 3H),
2.19 (ddd, J = 17.7, 9.5, 4.9 Hz, 1H), 1.92-1.82 (m, 1H), 1.61 (d, J = 7.0 Hz, 3H); 13C NMR (100 MHz,
CDCl3): δ, 185.4, 175.1, 163.86, 140.5, 139.1, 134.4, 134.3, 134.2, 134.1, 128.9, 128.8, 128.0, 127.8,
126.7, 126.3, 94.0, 78.8, 53.2, 51.1, 46.4, 34.9, 20.7, 17.5; HR-MS (ESI, m/z): [M+H]+ calculated for
C17H20NO2: 270.1489; found: 270.1502.
Minor Diastereomer: 1H NMR (400 MHz, CDCl3): δ, 7.37-7.30 (m, 2H), 7.30-7.26 (m, 1H), 7.20 (d,
J = 7.3 Hz, 2H), 6.31 (d, J = 2.5 Hz, 2H), 5.35 (s, 1H), 4.81 (q, J = 7.0 Hz, 1H), 3.63 (td, J = 9.7, 5.1
Hz, 1H), 3.45 (dd, J = 9.9, 8.2 Hz, 1H), 3.01 (s, 3H), 2.19 (ddd, J = 17.7, 9.5, 4.9 Hz, 1H), 1.98 (ddd, J
= 12.6, 11.4, 7.1 Hz, 1H), 1.58 (d, J = 7.0 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ, 185.4, 175.1,
163.9, 140.5, 139.1, 134.4, 134.3, 134.2, 134.1, 128.9, 128.8, 128.0, 127.8, 126.7, 126.3, 94.4, 78.7,
53.5, 51.0, 47.1, 34.9, 20.7, 17.3.
2-Methyl-1-((R)-1-phenylethyl)indolin-6-ol (11) (dr 3:1): 40 mg, 80% yield; Rf = 0.4 (20:80 =
EtOAc/n-Hexane); Maroon coloured liquid; FT-IR (neat): 2975, 2933, 2852, 2360, 2347, 1616, 1473,
1263, 1193, 1042, 750 cm-1; Major Diastereomer: 1H NMR (400 MHz, CDCl3): δ, 7.45 (d, J = 7.6 Hz,
2H), 7.32 (dd, J = 12.8, 5.0 Hz, 2H), 7.24 (dd, J = 8.2, 5.3 Hz, 1H), 6.81 (dd, J = 7.6, 4.0 Hz, 1H), 6.02
(d, J = 5.9 Hz, 1H), 5.55 (s, 1H), 4.52 (dd, J = 13.7, 6.9 Hz, 1H), 3.93-3.68 (m, 1H), 3.09 (dd, J = 14.2,
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8.9 Hz, 1H), 2.70 – 2.39 (m, 1H), 1.57 (d, J = 6.8 Hz, 3H), 1.34 (d, J = 6.1 Hz, 3H); C NMR (101
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