1916
J. Xiao et al.
PAPER
hexane, 5:95; 1.0 mL/min): tR (major) = 18.59 min, tR (minor) =
13.77 min.
IR (thin film): 2967, 2936, 2878, 1720, 1553, 1456, 1379, 1244,
758, 702 cm–1.
Rf = 0.18 (EtOAc–hexane, 1:4).
1H NMR (300 MHz, CDCl3): d = 9.71 (d, J = 2.5 Hz, 1 H), 7.36–
7.27 (m, 3 H), 7.20–7.17 (m, 2 H), 4.80–4.59 (m, 2 H), 3.84–3.75
(m, 1 H), 2.72–2.64 (m, 1 H), 1.55–1.43 (m, 2 H), 0.82 (t,
J = 7.5 Hz, 3 H).
13C NMR (75 MHz, CDCl3): d = 203.2, 136.8, 129.0, 128.2, 128.0,
78.5, 54.9, 42.6, 20.3, 10.6.
IR (thin film): 2976, 2935, 2879, 1726, 1553, 1489, 1377, 1010,
779, 717 cm–1.
1H NMR (300 MHz, CDCl3): d = 9.69 (d, J = 1.5 Hz, 1 H), 7.50–
7.46 (m, 2 H), 7.12–7.05 (m, 2 H), 4.82–4.56 (m, 2 H), 3.84–3.74
(m, 1 H), 2.83–2.70 (m, 1 H), 1.00 (d, J = 7.3 Hz, 3 H).
13C NMR (75 MHz, CDCl3): d = 201.8, 135.7, 132.3, 129.8, 122.1,
77.8, 48.2, 43.5, 12.2.
HRMS (ESI-TOF): m/z [M + H]+ calcd for C12H16NO3: 222.1130;
found: 222.1129.
HRMS (ESI-TOF): m/z [M + H]+ calcd for C11H13NO3Br:
286.0079; found: 286.0081.
(2S,3R)-2-Methyl-4-nitro-3-phenylbutanal (Table 3, entry 6)
The title compound was prepared from n-pentanal and (E)-(2-nitro-
vinyl)benzene according to the general procedure. Both enantio-
meric excess and diastereomeric excess were determined by HPLC
with an OD-H column (monitoring at 220 nm; 2-propanol–hexane,
2:98; 1.0 mL/min): tR (major) = 37.02 min, tR (minor) = 50.49 min.
(2S,3R)-3-(4-Methoxyphenyl)-2-methyl-4-nitrobutanal (Table
3, entry 3)
The title compound was prepared from propionaldehyde and (E)-1-
methoxy-4-(2-nitrovinyl)benzene according to the general proce-
dure. Both enantiomeric excess and diastereomeric ratio were deter-
mined by HPLC with an AS-H column (monitoring at 230 nm;
2-propanol–hexane, 5:95; 1.0 mL/min): tR (major) = 42.10 min,
tR (minor) = 60.77 min.
Rf = 0.41 (EtOAc–hexane, 1:4).
IR (thin film): 3030, 2959, 2931, 2872, 1722, 1603, 1553, 1454,
1379, 764, 702 cm–1.
1H NMR (300 MHz, CDCl3): d = 9.71 (d, J = 2.80 Hz, 1 H), 7.38–
7.27 (m, 3 H), 7.19–7.16 (m, 2 H), 4.87–4.61 (m, 2 H), 3.84–3.74
(m, 1 H), 2.77–2.60 (m, 1 H), 1.76–1.09 (m, 4 H), 0.81 (t, J =
7.0 Hz, 3 H).
13C NMR (75 MHz, CDCl3): d = 203.3, 136.8, 129.1, 128.2, 128.0,
78.4, 53.8, 43.2, 29.5, 19.8, 13.9.
HRMS (ESI-TOF): m/z [M + H]+ calcd for C13H18NO3: 236.1287;
found: 236.1290.
Rf = 0.13 (EtOAc–hexane, 1:4).
IR (thin film): 2978, 2937, 2839, 1726, 1612, 1557, 1514, 1379,
1253, 1182, 1033, 833, 725 cm–1.
1H NMR (300 MHz, CDCl3): d = 9.70 (d, J = 1.4 Hz, 1 H), 7.27–
7.07 (m, 2 H), 6.87–6.67 (m, 2 H), 4.78–4.60 (m, 2 H), 3.78 (s,
3 H), 3.78–3.73 (m, 1 H), 2.81–2.69 (m, 1 H), 0.99 (d, J = 7.2 Hz,
3 H).
13C NMR (75 MHz, CDCl3): d = 202.5, 129.2, 129.1, 128.3, 114.4,
(2S,3R)-2-Methyl-3-(naphthalen-1-yl)-4-nitrobutanal (Table 3,
entry 7)
78.3, 55.2, 48.6, 43.3, 12.0.
HRMS (ESI-TOF): m/z [M + H]+ calcd for C12H16NO4: 238.1079;
found: 238.1081.
The novel title compound was prepared from butyraldehyde and
(E)-1-(2-nitrovinyl)naphthalene according to the general procedure.
Both enantiomeric excess and diastereomeric ratio were determined
by HPLC with an AD-H column (monitoring at 220 nm; 2-propanol–
hexane, 0.8:99.2; 1.0 mL/min): tR (major) = 43.3 min, tR (minor) =
37.6 min.
(2S,3S)-3-(Furan-2-yl)-2-methyl-4-nitrobutanal (Table 3, entry
4)
The title compound was prepared from propionaldehyde and (E)-2-
(2-nitrovinyl)furan according to the general procedure. Both enan-
tiomeric excess and diastereomeric ratio were determined by HPLC
with an AD-H column (monitoring at 220 nm; 2-propanol–hexane,
0.8:99.2; 1.0 mL/min): tR (major) = 30.44 min, tR (minor) = 26.29
min.
Rf = 0.33 (EtOAc–hexane, 1:4).
IR (thin film): 3049, 2978, 2936, 1730, 1715, 1552, 1377, 1246,
799, 779 cm–1.
1H NMR (400 MHz, CDCl3): d = 9.75 (d, J = 1.6 Hz, 1 H), 8.14–
8.10 (m, 1 H), 7.88 (d, J = 8.0 Hz, 1 H), 7.80 (d, J = 8.2 Hz, 1 H),
7.61–7.41 (m, 3 H), 7.35 (d, J = 7.1 Hz, 1 H), 4.94–4.76 (m, 3 H),
3.01–2.96 (m, 1 H), 0.97 (d, J = 7.3 Hz, 3 H).
13C NMR (100 MHz, CDCl3): d = 202.5, 134.1, 133.3, 131.9, 129.2,
128.6, 126.9, 126.0, 125.3, 123.9, 122.4, 77.9, 49.2, 37.4, 12.5.
HRMS (ESI-TOF): m/z [M + H]+ calcd for C15H16NO3: 258.1130;
Rf = 0.17 (EtOAc–hexane, 1:4).
IR (thin film): 3152, 3123, 2974, 2938, 2880, 1724, 1557, 1458,
1377, 1150, 1013, 814, 741, 702 cm–1.
1H NMR (400 MHz, CDCl3): d = 9.70 (s, 1 H), 7.35 (s, 1 H), 6.30–
6.29 (m, 1 H), 6.17 (d, J = 3.22 Hz, 1 H), 4.77–4.67 (m, 2 H), 4.13–
4.05 (m, 1 H), 2.87–2.76 (m, 1 H), 1.06 (d, J = 7.31 Hz, 3 H).
found: 258.1138.
13C NMR (100 MHz, CDCl3): d = 201.6, 149.9, 142.7, 110.4, 108.7,
75.8, 47.1, 37.6, 11.0.
(2S,3R)-2-methyl-3-(naphthalen-2-yl)-4-nitrobutanal (Table 3,
entry 8)
HRMS (ESI-TOF): m/z [M + H]+ calcd for C9H12NO4: 198.0766;
found: 198.0761.
The title compound was prepared from butyraldehyde and (E)-2-(2-
nitrovinyl)naphthalene according to the general procedure. Both
enantiomeric excess and diastereomeric excess were determined by
HPLC with an AD-H column (monitoring at 220 nm; 2-propanol–
hexane, 0.8:99.2; 1.0 mL/min): tR (major) = 37.8 min, tR (minor) =
44.8 min.
1H NMR (400 MHz, CDCl3): d = 9.72 (d, J = 1.30 Hz, 1 H), 7.84–
7.78 (m, 3 H), 7.64 (d, J = 11.15 Hz, 1 H), 7.51–7.46 (m, 2 H),
7.33–7.25 (m, 1 H), 4.90–4.73 (m, 2 H), 4.01–3.93 (m, 1 H), 2.92–
2.81 (m, 1 H), 0.99 (d, J = 7.28 Hz, 3 H).
(2S,3R)-2-Ethyl-4-nitro-3-phenylbutanal (Table 3, entry 5)
The title compound was prepared from butyraldehyde and (E)-(2-
nitrovinyl)benzene according to the general procedure. The enan-
tiomeric ratio was determined by HPLC with an OD-H column
(monitoring at 220 nm; 2-propanol–hexane, 5:95; 1.0 mL/min):
tR (major) = 40.61 min, tR (minor) = 51.74 min. The diastereomeric
excess was determined by 1H NMR analysis.
Rf = 0.27 (EtOAc–hexane, 1:4).
Synthesis 2011, No. 12, 1912–1917 © Thieme Stuttgart · New York