General Procedure for Fukuyama Cross-Coupling Reaction

2.5 EXPERIMENTAL SECTION

2.5.3 General Procedure for Fukuyama Cross-Coupling Reaction

Preparation of Organozinc 16

According to the protocol of Orito and coworkers,³⁰ a flame-dried Schlenk flask was charged with zinc dust (2.80 g, 42.6 mmol, 1.5 equiv), TMSCl (0.14 mL, 1.12 mmol, 0.04 equiv), and THF (14 mL). The reaction was stirred at room temperature under N2 for 15 min. To the reaction was added (1-chloroethyl)benzene (4.00 g, 28.4 mmol, 1 equiv) dropwise. The reaction was stirred at 40 °C under N₂ for 4 h. The mixture was cooled to room temperature and the excess zinc dust was allowed to settle. The solution was titrated with I₂ according to Knochel and coworkers.³¹ The yellow organozinc solution was transferred to a flame-dried flask and stored under N2 at –20 °C. Concentrations of 1.0 M were obtained.

General Procedure for Synthesis of Phosphoramidite Ligands

A flame-dried flask was charged with PCl3 (1 mmol, 1 equiv) and CH2Cl2 (5 mL). The reaction was cooled to 0 °C and Et3N (5 mmol, 5 equiv) was added dropwise, followed by addition of amine (1 mmol, 1 equiv). The reaction was stirred at 23 °C under N₂ for 5 h. Diol (1 mmol, 1 equiv) was added and the reaction was stirred at 23 °C under N2 for 11 h. The reaction was filtered and concentrated. The crude residue was purified by column chromatography (100% CH₂Cl₂) to obtain a white foamy solid.

min. The thioester substrate 17 (0.2 mmol, 1 equiv), the (1-phenylethyl)zinc(II) chloride (16, 1.0 M THF, 0.28 mmol, 1.4 equiv), and ZnCl2 (1.0 M THF, 0.2 mmol, 1 equiv) were added to the reaction. The reaction was stirred at 28 °C for 12 h, after which time it was removed from the glovebox, quenched with 0.1 mL sat. aq. NH4Cl, dried (MgSO4), filtered, and concentrated. The crude residue was purified by silica gel chromatography.

1-(4-methoxyphenyl)-4-Phenylpentan-3-one (18a)

Prepared from S-phenyl 3-(4-methoxyphenyl)propanethioate (17a, 54.1 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 20:80 EtOAc:hexanes) to yield 46.8 mg (87% yield) of 18a as a slightly yellow oil. ¹H NMR (500 MHz, CDCl₃) ! 7.37 – 7.21 (m, 3H), 7.22 – 7.14 (m, 2H), 7.05 – 6.96 (m, 2H), 6.84 – 6.75 (m, 2H), 3.79 (s, 3H), 3.72 (q, J = 7.0 Hz, 1H), 2.88 – 2.57 (m, 4H), 1.39 (d, J = 7.0 Hz, 3H); ¹³C NMR (125 MHz, CDCl3) ! 210.0, 157.8, 140.4, 133.0, 129.2, 128.9, 127.8, 127.1, 113.7, 55.2, 53.2, 42.8, 29.1, 17.3; IR (NaCl/thin film): 3060, 3027, 2973, 2931, 2834, 1713, 1611, 1513, 1493, 1452, 1300, 1247 cm^-1; HRMS (MM) calc’d for [M–H]^– 267.1391, found 267.1391.

(E)-1-(4-methoxyphenyl)-4-Phenylpent-1-en-3-one (18b)

Prepared from (E)-S-phenyl 3-(4-methoxyphenyl)prop-2- enethioate (17b, 54.1 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 20:80 EtOAc:hexanes) to yield 52.0 mg (98% yield) of 18b as a slightly yellow oil. ¹H NMR (500 MHz, CDCl3) ! 7.59 (d, J = 15.9 Hz, 1H), 7.47 – 7.39 (m, 2H), 7.37 – 7.19 (m, 5H), 6.91 – 6.80 (m, 2H), 6.60 (d, J =

MeO

15.9 Hz, 1H), 4.01 (q, J = 6.9 Hz, 1H), 3.81 (s, 3H), 1.49 (d, J = 6.9 Hz, 3H); ¹³C NMR (125 MHz, CDCl3) ! 199.4, 161.4, 142.4, 140.9, 130.0, 128.9, 128.0, 127.2, 127.0, 122.4, 114.2, 55.3, 51.7, 17.9; IR (NaCl/thin film): 2971, 2930, 2837, 1684, 1654, 1598, 1572, 1511, 1254 cm^-1; HRMS (MM) calc’d for [M–H]^– 265.1234, found 265.1239.

Methyl 4-oxo-5-phenylhexanoate (18d)

Prepared from methyl 4-oxo-4-(phenylthio)butanoate (17d, 44.9 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 20:80 EtOAc:hexanes) to yield 30.3 mg (69% yield) of 18d as a slightly yellow oil. ¹H NMR (500 MHz, CDCl3) ! 7.39 – 7.16 (m, 5H), 3.79 (q, J = 7.0 Hz, 1H), 3.63 (s, 3H), 2.77 – 2.38 (m, 4H), 1.41 (d, J = 7.0 Hz, 3H); ¹³C NMR (125 MHz, CDCl3) ! 209.0, 173.2, 140.4, 128.9, 127.9, 127.2, 52.9, 51.7, 35.6, 27.9, 17.3; IR (NaCl/thin film): 3062, 3027, 2977, 2952, 2932, 1739, 1716, 1494, 1453, 1437, 1372, 1356, 1211 cm^-1; HRMS (MM) calc’d for [M+H]⁺ 221.1172, found 221.1173.

4-(2-phenylpropanoyl)Benzonitrile (18g)

Prepared from S-phenyl 4-cyanobenzothioate (17g, 47.9 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 20:80 EtOAc:hexanes) to yield 40.8 mg (87% yield) of 18g as a slightly yellow oil. ¹H NMR (500 MHz, CDCl₃) ! 8.04 – 7.94 (m, 2H), 7.71 – 7.61 (m, 2H), 7.39 – 7.17 (m, 5H), 4.61 (q, J = 6.8 Hz, 1H), 1.54 (d, J = 6.8 Hz, 3H); ¹³C NMR (125 MHz, CDCl3)

! 198.8, 140.4, 139.5, 132.3, 129.3, 129.1, 127.6, 127.3, 117.9, 115.9, 48.6, 19.3; IR

MeO O

NC Me

(NaCl/thin film): 3061, 2976, 2930, 2230, 1685, 1600, 1452, 1404, 1218, 1199 cm^-1; HRMS (MM) calc’d for [M–H]^– 234.0924, found 234.0932.

2-Phenyl-1-(o-tolyl)propan-1-one (18h)

Prepared from S-phenyl 2-methylbenzothioate (17h, 45.7 mg, 0.2 mmol).

The crude residue was purified by silica gel chromatography (2:98 EtOAc:hexanes) to yield 35.6 mg (79% yield) of 18h as a slightly yellow oil. ¹H NMR (500 MHz, CDCl₃) ! 7.53 (d, J = 7.7 Hz, 1H), 7.36 – 7.06 (m, 8H), 4.53 (q, J = 6.9 Hz, 1H), 2.34 (s, 3H), 1.55 (d, J = 6.9 Hz, 3H); ¹³C NMR (125 MHz, CDCl3) 204.6, 140.4, 138.5, 137.8, 131.5, 130.7, 128.8, 127.9, 127.8, 126.9, 125.3, 50.7, 20.8, 18.5; IR (NaCl/thin film): 3061, 3026, 2971, 2929, 2870, 1685, 1600, 1492, 1452, 1220 cm^-1; HRMS (MM) calc’d for [M–H]^– 238.1128, found 238.1128.

1-(3-methoxyphenyl)-2-Phenylpropan-1-one (18i)

Prepared from S-phenyl 3-methoxybenzothioate (17i, 48.9 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 EtOAc:hexanes) to yield 29.2 mg (61% yield) of 18i as a slightly yellow oil. ¹H NMR (500 MHz, CDCl₃) ! 7.56 – 7.44 (m, 2H), 7.34 – 7.25 (m, 5H), 7.24 – 7.15 (m, 1H), 7.02 (ddd, J = 8.2, 2.7, 0.9 Hz, 1H), 4.67 (q, J = 6.9 Hz, 1H), 3.80 (s, 3H), 1.53 (d, J

= 6.8 Hz, 3H); ¹³C NMR (125 MHz, CDCl₃) ! 200.1, 159.7, 141.5, 137.8, 129.4, 129.0, 127.7, 126.9, 121.4, 119.3, 113.1, 55.3, 48.0, 19.5; IR (NaCl/thin film): 3062, 3025, 2973, 2930, 2835, 1681, 1596, 1581, 1488, 1451, 1426, 1263 cm^-1; HRMS (MM) calc’d for [M–H]^– 239.1078, found 239.1088.

MeMe

Me OMe

1-(2-methoxyphenyl)-2-Phenylpropan-1-one (18j)

Prepared from S-phenyl 2-methoxybenzothioate (17j, 48.9 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 EtOAc:hexanes) to yield 19.2 mg (40% yield) of 18j as a slightly yellow oil. ¹H NMR (500 MHz, CDCl3) ! 7.48 (dd, J = 7.6, 1.8 Hz, 1H), 7.39 (ddd, J = 8.3, 7.3, 1.8 Hz, 1H), 7.34 – 7.13 (m, 5H), 6.95 – 6.89 (m, 2H), 4.75 (q, J = 7.0 Hz, 1H), 3.88 (s, 3H), 1.54 (d, J = 6.9 Hz, 5H); ¹³C NMR (125 MHz, CDCl3) ! 204.1, 157.5, 141.3, 135.1, 132.7, 130.4, 128.4, 128.1, 126.6, 120.5, 111.3, 55.3, 51.8, 18.7; IR (NaCl/thin film): 2929, 1736, 1666, 1597, 1485, 1466, 1284, 1245, 1198 cm^-1; HRMS (MM) calc’d for [M+H]⁺ 241.1223, found 241.1223.

1-(4-(dimethylamino)phenyl)-2-Phenylpropan-1-one (18k)

Prepared from S-phenyl 4-(dimethylamino)benzothioate (17k, 51.5 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 20:80 EtOAc:hexanes) to yield 24.4 mg (48% yield) of 18k as a slightly yellow oil. ¹H NMR (500 MHz, CDCl3) ! 7.95 – 7.85 (m, 2H), 7.36 – 7.23 (m, 4H), 7.23 – 7.13 (m, 1H), 6.62 – 6.55 (m, 2H), 4.64 (q, J = 6.9 Hz, 1H), 3.00 (s, 6H), 1.51 (d, J = 6.9 Hz, 3H); ¹³C NMR (125 MHz, CDCl₃) ! 198.3, 153.1, 142.6, 131.0, 130.9, 128.7, 126.5, 124.3, 110.6, 46.9, 39.9, 19.6; IR (NaCl/thin film): 3027, 2974, 2928, 2820, 1651, 1615, 1492, 1448, 1234, 1198 cm^-1; HRMS (MM) calc’d for [M+H]⁺ 254.1539, found 254.1543.

Me OMe

Me₂N Me

4-(2-phenylpropanoyl)Benzaldehyde (18l)

Prepared from S-phenyl 4-formylbenzothioate (17l, 48.5 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 20:80 EtOAc:hexanes) to yield 33.7 mg (71% yield) of 18l as a slightly yellow oil. ¹H NMR (500 MHz, CDCl3) ! 10.03 (s, 1H), 8.11 – 7.98 (m, 2H), 7.95 – 7.75 (m, 2H), 7.45 – 7.12 (m, 5H), 4.67 (q, J = 6.8 Hz, 1H), 1.55 (d, J = 6.9 Hz, 3H); ¹³C NMR (125 MHz, CDCl3) ! 199.7, 191.5, 140.7, 138.6, 129.7, 129.2, 128.9, 127.7, 127.2, 126.8, 48.6, 19.3; IR (NaCl/thin film): 3060, 3026, 2975, 2929, 1700, 1684, 1606, 1452, 1219 cm^-1; HRMS (MM) calc’d for [M–H]^– 237.0921, found 237.0909.

1-(4-fluorophenyl)-5-Phenylhexane-1,4-dione (18m)

Prepared from S-phenyl 4-(4-fluorophenyl)-4-oxobutanethioate (17m, 57.7 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 10:90 EtOAc:hexanes) to yield 50.3 mg (88% yield) of 18m as a slightly yellow oil. ¹H NMR (500 MHz, CDCl₃) ! 8.03 – 7.92 (m, 2H), 7.41 – 7.33 (m, 2H), 7.30 – 7.21 (m, 3H), 7.16 – 7.05 (m, 2H), 3.90 (q, J = 7.0 Hz, 1H), 3.28 (ddd, J = 18.1, 7.6, 5.8 Hz, 1H), 3.06 (dt, J = 18.1, 6.0 Hz, 1H), 2.88 (ddd, J = 18.2, 7.6, 5.7 Hz, 1H), 2.72 (dt, J = 18.2, 6.0 Hz, 1H), 1.44 (d, J = 7.0 Hz, 3H); ¹³C NMR (125 MHz, CDCl3) ! 209.5, 197.0, 165.7 (d, JC-F = 254.4 Hz), 140.6, 133.1, 130.7 (d, JC-F = 9.1 Hz), 128.9, 127.9, 127.2, 115.6 (d, JC-F = 21.8 Hz), 53.1, 34.8, 32.5, 17.4; IR (NaCl/thin film): 2975, 2913, 1714, 1685, 1597, 1506, 1410, 1231 cm^-1; HRMS (MM) calc’d for [M–H]^– 283.1140, found 283.1141.

Me O

F O

1-(4-chlorophenyl)-5-Phenylhexane-1,4-dione (18n)

Prepared from S-phenyl 4-(4-chlorophenyl)-4-oxobutanethioate (17n, 61.0 mg, 0.2 mmol). The crude residue was purified by silica gel chromatography (2:98 to 10:90 EtOAc:hexanes) to yield 52.8 mg (88% yield) of 18n as a slightly yellow oil. ¹H NMR (500 MHz, CDCl3) ! 7.91 – 7.83 (m, 2H), 7.48 – 7.22 (m, 7H), 3.89 (q, J = 7.0 Hz, 1H), 3.26 (ddd, J = 18.1, 7.5, 5.8 Hz, 1H), 3.04 (dt, J = 18.2, 5.9 Hz, 1H), 2.87 (ddd, J = 18.2, 7.6, 5.6 Hz, 1H), 2.72 (dt, J = 18.2, 6.0 Hz, 1H), 1.44 (d, J = 7.0 Hz, 3H); ¹³C NMR (125 MHz, CDCl₃) ! 209.5, 197.4, 140.6, 139.5, 134.9, 129.4, 128.9, 128.8, 127.9, 127.2, 53.1, 34.8, 32.5, 17.4; IR (NaCl/thin film):

3062, 3026, 2974, 2913, 1713, 1685, 1590, 1493, 1452, 1400, 1199 cm^-1; HRMS (MM) calc’d for [M–H]^– 299.0844, found 299.0870.

1-(4-methoxyphenyl)-4-Methylhexan-3-one (18o)

Prepared from S-phenyl 3-(4-methoxyphenyl)propanethioate (17a, 54.5 mg, 0.2 mmol) and Rieke organozinc 113b (0.5 M THF, 0.56 mL, 0.28 mmol). The crude residue was purified by silica gel chromatography (5:95 EtOAc:hexanes) to yield 41.4 mg (94% yield) of 18o as a slightly yellow oil. ¹H NMR (500 MHz, CDCl₃) ! 7.15 – 7.05 (m, 2H), 6.87 – 6.76 (m, 2H), 3.78 (s, 3H), 2.83 (t, J = 7.2 Hz, 2H), 2.81 – 2.66 (m, 2H), 2.41 (h, J = 6.9 Hz, 1H), 1.71 – 1.58 (m, 1H), 1.44 – 1.29 (m, 1H), 1.03 (d, J = 6.9 Hz, 3H), 0.83 (t, J = 7.4 Hz, 3H); ¹³C NMR (125 MHz, CDCl3) ! 213.9, 157.3, 133.4, 129.2, 113.8, 55.2, 48.0, 43.0, 28.8, 25.82, 15.7, 11.6; IR (NaCl/thin film): 2964, 2933, 2875, 2835, 1710, 1612, 1513, 1462, 1300, 1247 cm^-1; HRMS (MM) calc’d for [M]⁺ 220.1458, found 220.1414.

Cl O

MeO

Me Me

1-(4-methoxyphenyl)-4-Methylpentan-3-one (18p)

Prepared from S-phenyl 3-(4-methoxyphenyl)propanethioate (17a, 54.5 mg, 0.2 mmol) and Rieke organozinc 113c (0.5 M THF, 0.56 mL, 0.28 mmol). The crude residue was purified by silica gel chromatography (5:95 EtOAc:hexanes) to yield 38.2 mg (92% yield) of 18p as a slightly yellow oil. ¹H NMR (500 MHz, CDCl₃) ! 7.13 – 7.06 (m, 2H), 6.87 – 6.78 (m, 2H), 3.78 (s, 3H), 2.87 – 2.78 (m, 2H), 2.78 – 2.68 (m, 2H), 2.56 (hept, J = 7.0 Hz, 1H), 1.06 (d, J = 6.9 Hz, 6H); ¹³C NMR (125 MHz, CDCl₃) ! 214.0, 157.8, 133.4, 129.2, 113.8, 55.2, 42.2, 41.0, 28.9, 18.1;

IR (NaCl/thin film): 2968, 2933, 2873, 2835, 1710, 1612, 1513, 1465, 1300, 1246 cm^-1; HRMS (MM) calc’d for [M–H]^– 205.1234, found 205.1575.

1-Cyclopentyl-3-(4-methoxyphenyl)propan-1-one (18q)

Prepared from S-phenyl 3-(4-methoxyphenyl)propanethioate (17a, 54.5 mg, 0.2 mmol) and Rieke organozinc 113d (0.5 M THF, 0.56 mL, 0.28 mmol). The crude residue was purified by silica gel chromatography (5:95 EtOAc:hexanes) to yield 41.0 mg (88% yield) of 18q as a slightly yellow oil. ¹H NMR (500 MHz, CDCl3) ! 7.15 – 7.05 (m, 2H), 6.87 – 6.78 (m, 2H), 3.78 (s, 3H), 2.88 – 2.76 (m, 3H), 2.78 – 2.69 (m, 2H), 1.84 – 1.49 (m, 8H); ¹³C NMR (125 MHz, CDCl₃) ! 212.4, 157.8, 133.4, 129.2, 113.8, 55.2, 51.5, 43.6, 29.0, 28.7, 25.9; IR (NaCl/thin film): 2953, 2868, 1707, 1612, 1513, 1300, 1247 cm^-1; HRMS (MM) calc’d for [M–H]^– 233.1536, found 233.1530.

MeO

O Me Me

MeO

Dalam dokumen Development of Nickel-Catalyzed Asymmetric Reductive Cross-Coupling of Benzylic Electrophiles (Halaman 94-102)