D. Xu et al. / Tetrahedron: Asymmetry xxx (2016) xxx–xxx
11
4.3.8. Procedures for the synthesis of (R)-2,2-Dimethyl-4-nitro-
(100 MHz, CDCl3): d 203.2, 203.0, 140.5, 133.8, 130.2, 128.7,
128.7, 128.5, 128.3, 128.3, 126.4, 126.4, 77.4, 53.9, 53.8, 36.6,
36.2, 33.3, 33.0, 31.0, 30.7, 19.0, 18.7, 12.0, 12.0; HPLC (Chiralcel
3-phenylbutanal 18h
83% yield; yellow liquid; [
a]
20 = ꢀ9.3 (c 0.5, CHCl3); HRMS (EI)
D
calcd for C12H15NO3 [MꢀH]ꢀ 220.0979, found 220.0975; 1H NMR
(400 MHz, CDCl3): d 9.53 (s, 1H), 7.62 (t, J = 14.8 Hz, 2H), 7.48 (t,
J = 15.6 Hz, 3H), 4.86 (d, J = 1.6 Hz, 1H), 7.05 (d, J = 8.0 Hz, 1H),
3.80–3.77 (m, 1H), 1.14 (s, 3H), 1.01 (s, 3H); 13C NMR (100 MHz,
CDCl3): d 204.3, 133.8, 130.2, 129.4, 129.1, 128.7, 128.5, 128.2,
125.4, 76.3, 48.5, 48.2, 21.7, 18.9; HPLC (Chiralcel AD-H, n-hex-
AD-H, n-hexane:i-PrOH = 90:10, flow rate: 0.5 mL minꢀ1
k = 210 nm), Tmajor = 35.2, Tminor = 37.4, 99% ee.
,
4.3.14. Procedures for the synthesis of (2R,3R)-3-(Nitromethyl)-
5-phenyl-2-propylpentanal 20c
94% yield; yellow liquid; [a]
20 = +10.2 (c 1.0, CHCl3); HRMS (EI)
D
ane:i-PrOH = 97:3, flow rate: 0.5 mL minꢀ1
Tmajor = 25.6, Tminor = 27.0, 86% ee.
,
k = 254 nm),
calcd for C15H21NO3 [M+H]+ 264.1594, found 264.1599; 1H NMR
(400 MHz, CDCl3): d 9.64 (d, J = 6.8 Hz, 1H), 7.29–7.18 (m, 5H),
4.54–4.37 (m, 2H), 2.74–2.60 (m, 2H), 2.59–2.49 (m, 1H), 2.49–
2.04 (m, 1H), 1.80–1.45 (m, 2H), 1.44–1.22 (m, 2H), 0.95–0.89
(m, 5H); 13C NMR (100 MHz, CDCl3): d 203.2, 203.0, 140.5, 140.5,
128.6, 128.3, 128.3, 126.4, 126.4, 77.4, 77.0, 52.2, 52.0, 36.8, 36.6,
33.3, 33.1, 31.0, 30.7, 27.9, 27.6, 20.8, 20.8, 14.1, 14.0; HPLC (Chiral-
4.3.9. Procedures for the synthesis of (R)-2,2-Dimethyl-4-nitro-
3-(p-tolyl)butanal 18i
87% yield; yellow liquid; [
a
]
20 = ꢀ3.4 (c 1.0, CHCl3); HRMS (EI)
D
calcd for C13H17NO3 [MꢀH]ꢀ 234.1135, found 234.1136; 1H NMR
(400 MHz, CDCl3): d 9.45 (s, 1H), 7.05 (d, J = 8.0 Hz, 2H), 6.99 (d,
J = 8.4 Hz, 2H), 4.75 (d, J = 1.2 Hz, 1H), 4.60 (d, J = 4.0 Hz, 1H),
3.68–3.64 (m, 1H), 2.24 (s, 3H), 1.04 (s, 3H), 0.92 s, 3H); 13C NMR
(100 MHz, CDCl3): d 204.5, 172.1, 133.8, 130.3, 129.4, 129.2,
128.9, 76.4, 48.3, 48.2, 21.6, 18.9; HPLC (Chiralcel AD-H, n-hex-
cel AD-H, n-hexane:i-PrOH = 90:10, flow rate: 0.5 mL minꢀ1
k = 210 nm), Tmajor = 31.5, Tminor = 34.1, 99% ee.
,
4.3.15. Procedures for the synthesis of (2R,3R)-2-Isopropyl-3-
(nitromethyl)-5-phenylpentanal 20d
ane:i-PrOH = 97:3, flow rate: 0.5 mL minꢀ1, k = 254 nm), Tmajor
28.4, Tminor = 25.6, 87% ee.
=
93% yield; yellow liquid; [a]
20 = +38.6 (c 1.0, CHCl3); HRMS (EI)
D
calcd for C15H21NO3 [M+H]+ 264.1594, found 264.1596; 1H NMR
(400 MHz, CDCl3): d 9.81 (d, J = 2.4 Hz, 1H), 7.29 (t, J = 14.8 Hz,
2H), 7.21 (d, J = 7.2 Hz, 1H), 7.16 (t, J = 15.2 Hz, 2H), 4.57–4.50 (m,
1H), 4.48–4.45 (m, 1H), 2.70–2.62 (m, 4H), 2.49–2.45 (m, 1H),
2.12–2.04 (m, 2H), 1.79–1.73 (m, 2H), 1.08 (d, J = 7.2 Hz, 3H), 0.97
(d, J = 6.4 Hz, 3H); 13C NMR (100 MHz, CDCl3): d 204.8, 140.6,
128.7, 128.6, 128.4, 128.3, 126.3, 58.0, 35.6, 32.6, 31.8, 27.1, 21.0,
19.7; HPLC (Chiralcel AD-H, n-hexane:i-PrOH = 90:10, flow rate:
0.5 mL minꢀ1, k = 210 nm), Tmajor = 21.0, Tminor = 24.6, 99% ee.
4.3.10. Procedures for the synthesis of (R)-3-(4-Chlorophenyl)-
2,2-dimethyl-4-nitrobutanal 18j
89% yield; yellow liquid; [
a
]
20 = ꢀ8.8 (c 1.0, CHCl3); HRMS (EI)
D
calcd for C12H14ClNO3 [MꢀH]ꢀ 254.0589, found 254.0590; 1H
NMR (400 MHz, CDCl3): d 9.50 (s, 1H), 7.48 (t, J = 15.2 Hz, 2H),
7.31 (d, J = 8.4 Hz, 2H), 4.82 (d, J = 1.2 Hz, 1H), 4.71 (d, J = 4.4 Hz,
1H), 3.79–3.75 (m, 1H), 1.21 (s, 3H), 1.00 (s, 3H); 13C NMR
(100 MHz, CDCl3): d 203.9, 134.2, 134.0, 130.4, 130.2, 129.0,
128.5, 76.2, 48.2, 48.0, 21.7, 18.9; HPLC (Chiralcel AD-H, n-hex-
ane:i-PrOH = 96:4, flow rate: 1.0 mL minꢀ1, k = 254 nm), Tmajor
14.2, Tminor = 19.8, 90% ee.
=
4.3.16. Procedures for the synthesis of (R)-2-((R)-1-Nitro-4-
phenylbutan-2-yl)hexanal 20e
93% yield; yellow liquid; [a]
20 = +21.5 (c 1.0, CHCl3); HRMS (EI)
D
calcd for C16H23NO3 [M+H]+ 278.1751, found 278.1749; 1H NMR
(400 MHz, CDCl3): d 9.86 (s, 1H), 7.82–7.80 (m, 2H), 7.30–7.13
(m, 3H), 4.84–4.38 (m, 2H), 2.65–2.33 (m, 4H), 1.76–1.67 (m,
4H), 1.44–1.31 (m, 4H), 0.91 (d, J = 5.2 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d 203.0, 140.5, 128.6, 128.3, 128.3, 126.4, 77.4,
52.3, 36.6, 33.1, 31.0, 29.7, 25.2, 22.7, 13.8; HPLC (Chiralcel AD-H,
4.3.11. Procedures for the synthesis of (R)-3-(4-Bromophenyl)-
2,2-dimethyl-4-nitrobutanal 18k
82% yield; yellow liquid; [
a
]
20 = ꢀ4.0 (c 0.5, CHCl3); HRMS (EI)
D
calcd for C12H14BrNO3 [MꢀH]ꢀ 298.0084, found 298.0088; 1H
NMR (400 MHz, CDCl3): d 9.50 (s, 1H), 7.56–7.46 (m, 4H), 4.82 (d,
J = 1.2 Hz, 1H), 4.71 (d, J = 4.4 Hz, 1H), 3.78–3.74 (m, 1H), 1.13 (s,
3H), 1.04 (s, 3H); 13C NMR (100 MHz, CDCl3): d 203.8, 133.7,
132.8, 132.0, 130.7, 130.4, 1302, 129.4, 128.5, 76.1, 48.1, 48.0,
21.8, 19.0; HPLC (Chiralcel AD-H, n-hexane:i-PrOH = 96:4, flow
rate: 1.0 mL minꢀ1, k = 254 nm), Tmajor = 15.0, Tminor = 22.8, 86% ee.
n-hexane:i-PrOH = 96:4, flow rate: 0.5 mL minꢀ1
Tmajor = 16.0, Tminor = 16.5, 99% ee.
, k = 210 nm),
4.3.17. Procedures for the synthesis of (2R,3R)-2-Benzyl-3-
(nitromethyl)-5-phenylpentanal 20f
94% yield; yellow liquid; [a]
20 = +6.2 (c 1.0, CHCl3); HRMS (EI)
D
4.3.12. Procedures for the synthesis of (2R,3R)-2-Methyl-3-
(nitromethyl)-5-phenylpentanal 20a
calcd for C19H21NO3 [M+H]+ 312.1594, found 312.1591; 1H NMR
(400 MHz, CDCl3): d 9.64 (s, 1H), 7.63–7.42 (m, 5H), 7.32–6.96
(m, 5H), 4.57–4.50 (m, 2H), 3.08–3.04 (m, 2H), 2.76–2.65 (m,
3H), 1.90–1.85 (m, 3H); 13C NMR (100 MHz, CDCl3): d 202.6,
202.3, 140.3, 138.0, 137.8, 133.8, 130.2, 129.0, 128.8, 128.7,
128.7, 128.5, 128.4, 128.3, 127.0, 126.9, 126.5, 126.4, 77.4, 54.2,
53.7, 36.8, 36.6, 33.4, 33.2, 32.0, 31.7, 31.2, 30.4; HPLC (Chiralcel
91% yield; yellow liquid; [
a
]
20 = ꢀ0.6 (c 1.0, CHCl3); HRMS (EI)
D
calcd for C13H17NO3 [M+H]+ 236.1281, found 236.1284; 1H NMR
(400 MHz, CDCl3): d 9.61 (s, 1H), 7.31–7.27 (m, 2H), 7.25–7.19
(m, 2H), 7.17–7.14 (m, 1H), 4.55–4.51 (m, 1H), 4.46–4.41 (m,
1H), 2.82–2.72 (m, 1H), 2.70–2.63 (m, 1H), 2.61–2.54 (m, 2H),
1.71–1.64 (m, 2H), 1.62 (d, J = 5.2 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d 202.6, 140.5, 128.7, 128.3, 126.4, 77.4, 47.0, 36.8, 33.2,
30.2, 9.1; HPLC (Chiralcel AD-H, n-hexane:i-PrOH = 90:10, flow
rate: 0.5 mL minꢀ1, k = 210 nm), Tmajor = 15.5, Tminor = 12.8, 86% ee.
AD-H,
n-hexane:i-PrOH = 96:4,
flow
rate:
0.5 mL minꢀ1
,
k = 210 nm), Tmajor = 25.5, Tminor = 24.6, 97% ee.
Acknowledgments
4.3.13. Procedures for the synthesis of (2R,3R)-2-Ethyl-3-
We are grateful to Dr. Kevin S. Burgess from Columbus State
University, USA for his assistance in improving the English. This
work was supported by Doctor Research Project of Yunnan Normal
University (No. 150025), Yunnan Applied Basic Research Project
(Youth Project) and Fellowship for Outstanding PhD Student in
Yunnan Province.
(nitromethyl)-5-phenylpentanal 20b
90% yield; yellow liquid; [a]
20 = +21.4 (c 1.0, CHCl3); HRMS (EI)
D
calcd for C14H19NO3 [M+H]+ 250.1438, found 250.1435; 1H NMR
(400 MHz, CDCl3): d 9.67 (d, J = 3.6 Hz, 1H), 7.46–7.11 (m, 5H),
4.55–4.40 (m, 2H), 2.72–2.57 (m, 4H), 2.47–2.43 (m, 1H), 1.83–
1.67 (m, 4H), 1.57–1.50 (m, 1H), 1.00–0.91 (m, 3H); 13C NMR