M. Liu et al. / Tetrahedron Letters xxx (2018) xxx–xxx
5
as a white solid 4, yield 81%. m.p. 97 °C–98.5 °C; [
a
]
25 = +90° (c =
1H), 5.79–5.88(m, 1H), 5.49(s, 1H), 4.05–5.14(m, 2 H), 4.81(s,
1H), 4.61(d, J = 7.6 Hz, 1H), 4.23(d, J = 11.2 Hz, 1H), 3.98(d, J =
11.6 Hz, 1H), 3.78(s, 1H), 3.46(s, 3H), 2.90–3.03(m, 5H), 2.22(d, J
= 7.2 Hz, 2H), 1.61(s, 1H), 1.47–1.48(m, 2 H), 1.40–1.45(m, 2H),
0.88(s, 1H); 13C NMR (400 MHz, CDCl3) d: 180.82, 150.45, 145.59,
139.68, 137.65, 136.94, 130.76, 129.99, 129.11, 128.83, 128.30,
128.09, 127.74, 126.27, 125.87, 115.23, 110.51, 97.72, 81.21,
74.09, 70.99, 50.80, 50.21, 48.91, 46.85, 39.02, 27.39, 26.23,
25.05, 24.51 ppm; IR v: 3294, 2935, 2869, 1650, 1523, 1508,
D
1.0, CHCl3); 1H NMR (400 MHz, CDCl3) d (ppm): 7.52(t, J = 4.0 Hz,
4H), 7.37(s, 6H), 7.26(s, 1H), 6.78(d, J = 6.4 Hz, 1H), 5.94(s, 1H),
5.66(s, 1H), 5.00(d, J = 7.2 Hz, 1H), 5.08(d, J = 6.4 Hz, 1H),4.53(d, J
= 12.4 Hz, 1H), 4.19–4.27(m, 2H), 3.09(s, 1H); 13C NMR (400 MHz,
CDCl3) d: 145.4, 136.9, 129.2, 128.9, 128.3, 128.3, 126.3, 126.1,
101.8, 101.6, 98.3, 81.6, 74.9, 74.5, 46.6 ppm; IR m: 3474, 3416,
1635, 1618, 1400, 1221, 1121, 771, 698 cmꢀ1; ESI-MS m/z: Calcd
for C20H24N2O4[M+]340.15, found 340.10.
(8S,9S)-9-amino-(9-deoxy)-epiquinine 531–33 and isothio-
1454, 1226, 1126, 1096, 748, 696 cmꢀ1, HRMS m/z: Caled for C40
42N4O4S{[M+H]+} 675.3006, found 675.3009.
Preparation of 7e: 1.07 g (3 mmol) of 4, 20 mL of freshly distilled
tetrahydrofuran was added to the reaction flask and stirred com-
pletely to dissolve. A solution of 438 L of 3,5-bis (trifluoromethyl)
-
cyanate 6 was prepared according to the literatures.29
H
Preparation of 7a: A solution of 4 (272.7 mg, 2.25 mmol) was
added to stirred solution 5 (550.2 mg, 1.50 mmol) in THF (5 mL)
at room temperature. After 24 h, the solvent was removed under
reduced pressure. The residue was purified by recrystallization to
afford the product 7a (517.8 mg. 71% yield). m.p. 125 °C–127 °C;
l
phenyl was added, The reaction was carried out in 3 h at room
temputure. The solvent was subsequently removed. The residue
was purified by flash chromatography on silica gel (PE/EA = 20:1)
to afford product 7e (1.33 g, 71% yield) as a white solid. m.p.
[a]
25 = +106° (c = 1.0, CHCl3); 1H NMR (400 MHz, CDCl3) d (ppm):
D
7.99(d, J = 9.2 Hz, 1H), 7.53–7.57(m, 5H), 7.35–7.41(m, 12H), 6.70
(d, J = 6.4 Hz, 1H), 5.90(s, 1H), 5.59–5.68(m, 1H), 5.53(s, 1H), 5.35
(s, 1H), 4.90–4.97(m, 2 H), 4.73(t, J = 10.2 Hz, 2 H), 4.02(d, J = 8.8
Hz, 2 H), 3.95(s, 3 H), 2.90–3.22(m, 3 H), 2.65–2.73(m, 2 H), 2.24
(s, 1H), 1.48–1.63(m, 3 H), 0.83–0.89(m, 1H); 13C NMR (400 MHz,
CDCl3) d: 171.20, 157.91, 147.63, 145.73, 141.07, 137.43, 136.95,
132.01, 129.21, 128.99, 128.77, 128.30, 128.10, 126.32, 126.04,
125.71, 121.88, 114.78, 101.84, 100.80, 98.31, 97.99, 81.76, 74.52,
71.43, 55.71, 55.50, 50.28, 46.53, 40.59, 39.44, 27.65, 27.32,
21.07 ppm, 14.19; IR v: 1647, 1620, 1508, 1358, 1227, 1126,
1088, 1030, 760, 698 cmꢀ1; HRMS m/z: Calcd for C41H44N4O5S{[M
+H]+} 705.3111; found 705.3102.
72.5 °C–74.5 °C; [a]
25 = +90° (c = 1.0, CHCl3); 1H NMR (400 MHz,
D
CDCl3) d (ppm): 8.20(s, 1H), 7.44–7.52(m, 5H), 7.33–7.36(m, 2H),
7.10–7.21(m, 6H), 6.75(d, J = 6.4 Hz, 1H), 6.58(s, 1H), 5.70(s, 1H),
5.19(d, J = 6.4 Hz, 1H), 5.04(d, J = 8.4 Hz, 1H), 4.92(d, J = 7.6 Hz,
1H), 4.39(d, J = 12.4 Hz, 1H), 3.32(d, J = 6.8 Hz, 1H), 4.24(d, J =
12.0 Hz, 1H); 13C NMR (400 MHz, CDCl3) d: 179.38, 146.71,
139.16, 135.92, 135.56, 131.77, 131.43, 130.06, 129.38, 128.41,
128.30, 126.18, 124.26, 121.88, 121.55, 117.84, 103.67, 100.36,
98.76, 82.08, 74.65, 71.72, 49.07, 29.71 ppm; IR v: 1628, 1508,
1458, 1385, 1277, 1177, 1130, 972, 760, 698 cmꢀ1; HRMS m/z:
Caled for C29H24N2O4SF6 {[M+Na]+} 633.1259, found 633.1260.
Preparation of 7b: The synthesis route was as the same as 7a,
except the starting material was quinidine. The spectra data for
Typical catalytic asymmetric Henry reaction of nitroalkane to
aldehyde
7b was: m.p. 104 °C–106 °C; [a]
25 = +231° (c = 1.0, CHCl3); 1H
D
NMR (400 MHz, CDCl3) d (ppm): 8.02(d, J = 9.2 Hz, 1H), 7.46–7.75
(m, 7H), 7.36–7.41(m, 10H), 6.64(d, J = 6.0 Hz, 1H), 5.85(s, 1H),
5.56–5.64(m, 2H), 4.93–5.03(m, 2H), 4.72(d, J = 6.8 Hz, 2H), 4.05
(t, J = 7.2 Hz, 2H), 4.00(s, 3H), 3.39–3.52(m, 2H), 3.21(m, 2H), 3.83
(t, J = 5.0 Hz, 2H), 2.32(s, 1H), 1.61–1.71(m, 3H), 1.36–1.43(m,
1H), 0.88–0.98 (m, 1H); 13C NMR (400 MHz, CDCl3) d: 192.51,
182.20, 158.16, 147.81, 145.66, 144.91, 137.50, 136.91, 134.50,
131.91, 129.77, 129.16, 128.98, 128.24, 126.36, 122.13, 102.08,
101.44, 98.04, 81.67, 74.47, 71.30, 55.93, 53.50, 49.87, 41.43,
36.01, 29.71, 26.71, 24.75, 11.71 ppm; IR v: 2931, 2869, 1643,
Aldehyde (0.2 mmol), nitroalkane (2 mmol), thiourea catalyst
7a (0.01 mmol, 7.2 mg) were dissolved in toluene (1 mL) (or in
toluene/H2O 7:3) at room temperature. The mixture was stirred
at room temperature for 0.5 h. Then, the pyridine (0.04 mmol,
3.2 lL) were added sequentially at room temperature. The mixture
was stirred for 24 h at ꢀ30 °C, and the residue was purified by flash
chromatography on silica gel (petroleum ether/ethyl acetate) to
provide the desired product. The enantiomeric purity of the pro-
duct was determined by HPLC analysis. The absolute configura-
tions of the products were assigned by comparison to literature
data.34
1620, 1527, 1523, 1261, 1226, 1091, 1029, 918, 759, 696 cmꢀ1
;
HRMS m/z: Calcd for
C
41H44N4O5S{[M+H]+} 705.3111, found
705.3104.
Preparation of 7c: The synthesis route was as the same as 7a,
except the starting material was hydroquinine. The spectra data
for 7c was: 1H NMR (400 MHz, CDCl3) d (ppm): 8.01(d, J = 9.2 Hz,
1H), 7.81(t, J = 1.2 Hz, 1H), 7.34–7.50(m, 14H), 6.60(d, J = 5.6 Hz,
1H), 5.82(s, 1H), 5.54(s, 1H), 5.14–5.16(m, 1H), 4.70(t, J = 16.4 Hz,
2H), 4.05(d, J = 7.6 Hz, 1H), 4.00(s, 3H), 3.53(d, J = 8.8 Hz, 1H),
3.35(d, J = 11.4 Hz, 1H), 2.87(t, J = 2.8 Hz, 1H), 2.65–2.67(m, 1H),
2.04(s, 2H), 1.74(s, 2H), 1.21–1.30(m, 5H), 1.03–1.07(m, 1H),
1.00–1.03(m 1H), 0.79(t, J = 7.4 Hz, 3H); 13C NMR (400 MHz, CDCl3)
d: 182.13, 158.21, 147.79, 145.66, 144.96, 137.45, 136.91, 131.95,
129.13, 128.96, 128.22, 126.35, 122.16, 102.02, 101.69, 101.44,
98.05, 81.62, 74.43, 71.26, 65.28, 56.47, 55.94, 49.86, 41.98,
41.41, 30.14, 29.12, 29.67, 24.78, 23.35, 23.10, 14.10, 11.65,
11.10 ppm; IR v: 3301, 2981, 2931, 2873, 1693, 1504, 1411,
1373, 1257, 1211, 968, 763 cmꢀ1. HRMS m/z: Caled for C41H46N4-
O5S{[M+H]+} 707.3268, found 707.3258.
Acknowledgments
We thank the National Natural Science Foundation of China
(21172261) and Natural Science Basic Research Plan in Shaanxi
Province of China (2017JM8060) for financial support.
A. Supplementary data
Supplementary data associated with this article can be found, in
References
Preparation of 7d: The synthesis route was as the same as 7a,
except the starting material was cinchonine. The spectra data for
7d was: m.p. 126.2 °C–127.4 °C; [a]
25 = +155.9° (c = 1.0, CHCl3);
D
1H NMR (400 MHz, CDCl3) d (ppm): 8.16(d, J = 8.4 Hz, 1H), 7.72(s,
1H), 7.39–7.50(m, 12H), 6.99(d, J = 7.6 Hz, 1H), 6.54(t, J = 2 Hz,