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Z. Dong et al. / Tetrahedron: Asymmetry 23 (2012) 1550–1556
(m, 3H). 13C NMR (100 MHz, DMSO-d6) d 182.45, 182.28, 168.04,
166.77, 150.47, 148.13, 141.45, 141.01, 140.52, 129.97, 129.59,
127.90, 127.33, 126.57, 126.16, 126.07, 125.04, 124.38, 123.32,
114.90, 72.36, 62.05, 60.78, 59.33, 54.93, 28.96, 26.96, 26.17,
25.41. HRMS (ESI) Calcd for C32H33N4O3H [M+H]+ 521.25527.
Found 521.25472
1H), 4.18–4.11 (m, 1H), 2.23 (s, 3H), 1.91 (s, 3H). 13C NMR
(100 MHz, CDCl3): d 200.4, 199.5, 134.1, 131.5, 128.6, 121.7, 76.8,
69.4, 41.2, 29.4, 28.6. Chiralpak AD-H column (250 Â 4.6 mm),
10% i-PrOH/hexane, 1 mL/min, 220 nm. tmajor = 29.757 min; tminor
=
27.990 min, ee = 93%.
Compound 11e: 1H NMR (400 MHz, CDCl3) d 7.61 (d, J = 8.1 Hz,
2H), 7.34 (d, J = 8.1 Hz, 2H), 4.66 (m, J = 5.9 Hz, 2H), 4.39 (m, 2H),
2.31 (s, 3H), 2.00 (s, 3H). 13C NMR (100 MHz, CDCl3) d 201.18,
200.31, 140.32, 131.02, 130.64, 128.50, 126.29, 77.57, 70.30,
42.43, 30.46, 29.75. Chiralpak OD-H column (250 Â 4.6 mm), 10%
Compound 1c: yellow solid (82%), mp: 198–200 °C. 1H NMR
(400 MHz, CDCl3) d 8.85 (d, 1H), 8.66 (d, 1H), 8.20 (d, 1H), 7.78
(m, 3H), 7.22–6.82 (m, 3H), 6.57 (s, 1H), 5.86 (s, 1H), 5.22–5.25
(m, 2H), 4.40 (s, 1H), 4.23 (s, 1H), 3.77 (s, 1H), 3.42–2.72 (m, 4H),
2.53 (s, 1H), 1.85–1.77 (m, 4H), 1.26 (s, 2H), 0.91 (d, J = 6.4 Hz,
2H). 13C NMR (100 MHz, CDCl3) d 183.36, 182.41, 168.29, 167.15,
150.54, 148.60, 143.65, 140.48, 140.07, 138.65, 130.51, 129.93,
128.21, 127.86, 126.51, 125.00, 124.70, 116.53, 73.56, 61.97,
54.09, 40.73, 38.60, 37.65, 31.88, 29.68, 26.99, 25.16, 24.91. HRMS
(ESI) Calcd for C32H33N4O3H [M+H]+ 521.25527. Found 521.25472
Compound 1d: yellow solid (78%), mp: 177–179 °C. 1H NMR
(400 MHz, CDCl3) d 8.70 (s, 1H), 8.50 (s, 1H), 8.08 (d, J = 8.1 Hz,
1H), 7.66 (m, 3H), 7.21 (s, 1H), 7.04 (s, 3H), 6.37 (s, 1H), 5.67 (s,
1H), 5.05 (m, 2H), 4.38 (s, 1H), 4.10 (s, 1H), 3.72 (s, 1H), 3.39 (s,
1H), 2.88–3.06 (m, 2H), 2.77 (d, J = 15.9 Hz, 1H), 2.49 (d, 1H),
1.58–1.86 (m, 6H), 1.26 (s, 2H). 13C NMR (100 MHz, CDCl3) d
183.14, 182.51, 168.87, 166.94, 150.32, 148.28, 140.16, 138.05,
130.06, 129.92, 128.24, 127.92, 127.01, 126.28, 125.13, 124.73,
123.02, 116.70, 73.51, 61.83, 54.09, 40.90, 39.07, 37.26, 31.90,
29.33, 26.82, 25.10, 24.54. HRMS (ESI) Calcd for C32H33N4O3H
[M+H]+ 521.25527. Found 521.25472
i-PrOH/hexane, 1 mL/min, 220 nm. tmajor = 24.173 min; tminor
27.480 min, ee = 99% after recrystallized from i-PrOH.
=
Compound 11f: 1H NMR (400 MHz, CDCl3) d 7.13 (d, J = 8.0 Hz,
2H), 7.06 (d, J = 8.2 Hz, 2H), 4.61 (m, 2H), 4.36 (d, J = 10.9 Hz, 1H),
4.21 (m, 1H), 2.30 (s, 3H), 2.29 (s, 3H), 1.94 (s, 3H). 13C NMR
(100 MHz, CDCl3)
d 201.90, 201.14, 138.37, 132.83, 130.01,
127.79, 78.37, 70.83, 42.47, 30.42, 29.47, 21.07. Chiralpak AD-H
column (250 Â 4.6 mm), 10% i-PrOH/hexane, 1 mL/min, 220 nm.
tmajor = 18.097 min; tminor = 11.007 min, ee = 89%.
Compound 11g: 1H NMR (400 MHz, CDCl3) d 7.10 (d, J = 8.6 Hz,
2H), 6.84 (d, J = 8.2 Hz, 2H), 4.59 (d, J = 6.4 Hz, 2H), 4.33 (d,
J = 10.9 Hz, 1H), 4.21 (m, 1H), 3.77 (s, 3H), 2.28 (s, 3H), 1.94 (s,
3H). 13C NMR (100 MHz, CDCl3) d 201.89, 201.21, 159.51, 129.08,
127.66, 114.68, 78.45, 70.88, 55.22, 42.13, 30.39, 29.60. Chiralpak
AD-H column (250 Â 4.6 mm), 10% i-PrOH/hexane, 1 mL/min,
220 nm. tmajor = 25.990 min; tminor = 16.592 min, ee = 90%.
11 h 1H NMR (400 MHz, CDCl3) d 7.63 (d, J = 8.0 Hz, 1H), 7.29
(m, 1H), 7.16 (m, 2H), 4.84 (m, 1H), 4.73 (m, 1H), 4.67 (dd, 1H),
4.60 (d, J = 9.6 Hz, 1H), 2.29 (s, 3H), 2.05 (s, 3H). 13C NMR
Compound 4: white solid (35%), mp: 260–263 °C. 1H NMR
(400 MHz, DMSO-d6) d 8.09 (d, J = 8.5 Hz, 1H), 7.26 (s, 3H), 5.52
(s, 1H), 4.56 (s, 1H), 3.12 (dd, J = 16.0, 3.9 Hz, 1H), 2.85 (d,
J = 16.2 Hz, 1H). 13C NMR (100 Hz, DMSO-d6) d 182.80, 167.84,
141.95, 140.49, 127.86, 126.62, 125.08, 124.22, 72.39, 60.80. HRMS
(ESI) Calcd for C22H21N2O4H [M+H]+ 377.1501. Found 377.1500.
(100 MHz, CDCl3)
d 201.97, 200.90, 135.09, 134.03, 129.42,
128.28, 124.57, 76.27, 69.08, 41.08, 31.02, 28.46. Chiralpak OD-H
column (250 Â 4.6 mm), 10% i-PrOH/hexane, 1 mL/min, 220 nm.
tmajor = 24.022 min; tminor = 22.217 min, ee = 96%.
Compound 11i: 1H NMR (400 MHz, CDCl3) d 7.43 (d, J = 9.3 Hz,
1H), 7.31–7.21 (m, 2H), 7.15 (m, 1H), 4.88 (m, 1H), 4.73 (m, 1H),
4.67 (dd, 1H), 4.60 (d, J = 9.9 Hz, 1H), 2.29 (s, 3H), 2.04 (s, 3H).
13C NMR (100 MHz, CDCl3) d 201.89, 200.92, 133.86, 133.46,
130.56, 129.72, 129.06, 127.67, 76.20, 68.84, 38.86, 30.89, 28.36.
Chiralpak OD-H column (250 Â 4.6 mm), 5% i-PrOH/hexane,
1 mL/min, 230 nm. tmajor = 13.132 min; tminor = 12.298 min,
ee = 94%.
4.3. Standard procedure for the asymmetric Michael addition
In a 10 mL round-bottomed flask, 1,3-dicarbonyl compound 9
was added to the agitated solution of nitroolefin 10 (0.2 mmoL)
and catalyst 1a (1 mg) in 1 mL of dicholomethane at 15 °C. After
48 h, the reaction was monitored by TLC, condensed under reduced
pressure and subjected to flash chromatography column to give
the pure product 11.
Compound 11j: 1H NMR (400 MHz, CDCl3) d 7.08 (s, 1H), 6.95 (s,
1H), 6.83 (d, J = 8.4 Hz, 1H), 6.57 (d, J = 8.4 Hz, 1H), 4.84 (m, 1H),
4.73 (m, 1H), 4.67 (dd, 1H), 4.60 (d, J = 9.6 Hz, 1H), 3.68 (s, 3H),
2.29 (s, 3H), 2.06 (s, 3H). 13C NMR (100 MHz, CDCl3) d 202.31,
201.61, 157.04, 130.26, 129.76, 123.53, 121.17, 111.26, 76.56,
68.98, 55.44, 38.99, 30.44, 28.79. Chiralpak OD-H column
Compound 11a: 1H NMR (400 MHz, CDCl3) d 7.30 (t, J = 8.9 Hz,
3H), 7.19 (d, J = 8.1 Hz, 2H), 4.64 (d, J = 6.9 Hz, 2H), 4.38 (d,
J = 10.7 Hz, 1H), 4.23 (d, J = 12.9 Hz, 1H), 2.27 (s, 3H), 1.93 (s, 3H).
13C NMR (101 MHz, CDCl3) d 201.76, 201.11, 136.06, 129.30,
128.51, 127.97, 78.15, 70.57, 42.81, 30.46, 29.69. Chiralpak AD-H
column (250 Â 4.6 mm), 10% i-PrOH/hexane; 1 mL/min, 220 nm;
tmajor = 16.425 min, tminor = 11.800 min, ee = 93%.
(250 Â 4.6 mm), 5% i-PrOH/hexane, 0.5 mL/ min, 215 nm. tmajor
=
44.573 min; tminor = 42.190 min, ee = 86%.
Compound 11b: 1H NMR (400 MHz, CDCl3) d 7.18 (dd, J = 8.7,
5.1 Hz, 2H), 7.03 (t, J = 8.6 Hz, 2H), 4.63–4.59 (m, 2H), 4.34 (d,
J = 10.8 Hz, 1H), 4.24 (ddd, J = 10.9, 7.0, 5.5 Hz, 1H), 2.30 (s, 3H),
1.97 (s, 3H). 13C NMR (100 MHz, CDCl3): d 221.4, 169.4, 137.6,
128.7, 126.8, 126.1, 77.62, 62.4, 62.3, 42.2, 38.0, 31.6, 19.4, 14.0.
Chiralpak AD-H column (250 Â 4.6 mm), 10% i-PrOH/hexane,
Compound 11k: 1H NMR (400 MHz, CDCl3) d 7.36 (s, 1H), 6.30
(s, 1H), 6.18 (s, 1H), 4.67 (d, J = 5.4 Hz, 2H), 4.45–4.29 (m, 2H),
2.28 (s, 3H), 2.09 (s, 3H). 13C NMR (101 MHz, CDCl3) d 201.57 (s,
3H), 200.72 (s, 1H), 110.87 (s, 6H), 108.87 (s, 5H), 75.83 (s, 6H),
67.98 (s, 7H), 36.45 (s, 1H), 30.63 (s, 5H), 29.28 (s, 6H). Chiralpak
AD-H column (250 Â 4.6 mm), 10% i-PrOH/hexane, 1 mL/min,
220 nm. tmajor = 14.593 min; tminor = 12.367 min, ee = 77%.
1 mL/min,
ee = 90%.
220 nm.
tmajor = 28.375 min,
tminor = 14.435 min,
Compound 11l: 1H NMR (400 MHz, CDCl3) d 7.24 (d, J = 5.1 Hz,
1H), 6.96–6.91 (m, 1H), 6.89 (d, J = 3.4 Hz, 1H), 4.66 (d, J = 6.0 Hz,
2H), 4.58–4.51 (m, 1H), 4.41 (d, J = 10.1 Hz, 1H), 2.30 (s, 3H), 2.08
(s, 3H). 13C NMR (100 MHz, CDCl3) d 201.49, 200.69, 138.46,
127.39, 127.01, 125.74, 78.51, 71.01, 38.23, 30.57, 29.67. Chiralpak
AD-H column (250 Â 4.6 mm), 10% i-PrOH/hexane, 0.8 mL/min,
220 nm. tmajor = 24.047 min, tminor = 17.348 min, ee = 78%.
Compound 11c: 1H NMR (400 MHz, CDCl3) d 7.30 (d, J = 9.7 Hz,
2H), 7.14 (d, J = 8.4 Hz, 2H), 4.62 (d, J = 6.2 Hz, 2H), 4.33 (d,
J = 10.7 Hz, 1H), 4.29–4.17 (m, 1H), 2.29 (s, 3H), 1.98 (s, 3H). 13C
NMR (100 MHz, CDCl3) d 201.41, 200.63, 134.61, 134.52, 129.54,
129.35, 77.92, 70.47, 42.15, 30.44, 29.72. Chiralpak AD-H column
(250 Â 4.6 mm), 10% i-PrOH/hexane, 1 mL/min, 230 nm. tma-
jor = 42.300 min; tminor = 14.697 min, ee = 88%.
Compound 11m: Major diastereomer: 1H NMR (400 MHz,
CDCl3) d 7.85 (d, J = 7.2 Hz, 2H), 7.55 (m, 1H), 7.42 (t, J = 7.8 Hz,
2H), 7.30 (m, 3H), 7.20(m, 3H), 4.96 (d, J = 1.7 Hz, 1H), 4.92(m,
Compound 11d: 1H NMR (400 MHz, CDCl3) d 7.40 (d, J = 8.5 Hz,
2H), 7.01 (d, J = 8.5 Hz, 2H), 4.56–4.52 (m, 2H), 4.26 (d, J = 10.7 Hz,