10.1002/ejoc.201701695
European Journal of Organic Chemistry
FULL PAPER
[M+Na]+: 261.0739, found 261.0737; IR: v=3385.38, 1742.61, 1627.05,
1598.13, 1233.11, 1097.76, 767.18, 694.49 cm-1
ethyl (2R,3R)-2,3-dihydroxy-4-oxo-4-(o-tolyl)butanoate (syn-3d):
Yield: 46% 23.1 mg; colorless oil; [α]2D5 = +37.0 (c 0.199, in CHCl3); 96%
ee, determined by HPLC analysis (Chiralpak OD-H column, hexane/i-
PrOH = 19:1, flow rate=1.0 mL/min, λ=254 nm, tmajor=11.48 min,
tminor=16.12 min). 1H NMR (400 MHz, CDCl3) δ 7.62 (d, J = 7.7 Hz, 1H),
7.48 (t, J = 7.4 Hz, 1H), 7.35 (t, J = 7.5 Hz, 2H), 5.34 (d, J = 3.9 Hz, 1H),
4.38 – 4.32 (m, 2H), 4.09 (d, J = 5.4 Hz, 1H), 3.04 (d, J = 6.0 Hz, 1H),
2.52 (s, 3H), 1.38 (t, J = 7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ
200.88, 171.58, 139.57, 133.77, 132.46, 132.41, 127.91, 125.91, 75.93,
72.02, 62.57, 20.66, 14.27. HRMS (EI): calcd for C13H16O5Na [M+Na]+:
275.0895, found 275.0892; IR: v=3346.10, 1743.20, 1623.67, 1597.79,
1449.46, 1383.97, 1098.03, 767.01, 695.28 cm-1
ethyl (2S, 3R)-2,3-dihydroxy-4-oxo-4-phenylbutanoate (anti-3a):
Yield: 58%, 27.6 mg; white solid, m.p.= 61-62℃; [α]2D5 = -20.5 (c 0.205,
in CHCl3); 93% ee, determined by HPLC analysis (Chiralpak AS
column, hexane/i-PrOH = 4:1, flow rate = 1.0 mL/min, λ = 254 nm, tmajor
= 27.19 min, tminor = 36.46 min). 1H NMR (400 MHz, CDCl3) δ 7.96 (dd, J
= 19.5, 7.9 Hz, 2H), 7.76 – 7.63 (m, 1H), 7.52 (dd, J = 21.5, 13.9 Hz,
2H), 5.35 (s, 1H), 4.65 (d, J = 1.8 Hz, 1H), 4.05 (dq, J = 10.8, 7.2 Hz,
2H), 1.18 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 197.94,
170.80, 134.62, 134.45, 129.47, 128.82, 76.77, 73.93, 62.54, 14.32.
HRMS (EI): calcd for C12H14O5Na [M+Na]+: 261.0739, found 261.0737;
IR: v=3385.38, 1742.61, 1627.05, 1598.13, 1233.11, 1097.76, 767.18,
694.49 cm-1
ethyl (2R,3S)-2,3-dihydroxy-4-oxo-4-(o-tolyl)butanoate (anti-3d):
Yield: 47%, 23.6 mg; colorless oil; [α]2D5 = -21.1 (c 0.199, in CHCl3); 99%
ee, determined by HPLC analysis (Chiralpak OD-H column, hexane/i-
PrOH = 19:1, flow rate = 1.0 mL/min, λ = 254 nm, tmajor = 46.20 min,
tminor = 47.20 min). 1H NMR (400 MHz, CDCl3) δ 7.63 (t, J = 7.9 Hz, 1H),
7.48 – 7.42 (m, 1H), 7.37 – 7.31 (m, 2H), 5.34 (s, 1H), 4.56 (s, 1H),
4.10 (q, J = 7.2 Hz, 2H), 2.55 (s, 3H), 1.24 (t, J = 7.1 Hz, 2H); 13C NMR
(100 MHz, CDCl3) δ 199.91, 170.61, 139.73, 133.78, 132.67, 132.47,
128.57, 125.85, 77.21, 73.64, 62.35, 20.79, 14.17. HRMS (EI): calcd for
C13H16O5Na [M+Na]+: 275.0895, found 275.0892; IR: v=3346.10,
1743.20, 1623.67, 1597.79, 1449.46, 1383.97, 1098.03, 767.01, 695.28
cm-1
ethyl (2R, 3R)-2,3-dihydroxy-4-oxo-4-(p-tolyl)butanoate (syn-3b):
Yield: 33%, 16.6 mg; colorless oil; [α]2D5 = +23.9 (c 0.197, in CHCl3);
96% ee, determined by HPLC analysis (Chiralpak AS column, hexane/i-
PrOH = 4:1, flow rate = 1.0 mL/min, λ = 254 nm, tmajor = 16.68 min, tminor
= 24.69 min). 1H NMR (400 MHz, CDCl3) δ 7.97 – 7.88 (d, 2H), 7.33 (d,
J = 7.8 Hz, 2H), 5.41 (s, 1H), 4.55 (s, 1H), 4.37 (q, J = 7.1 Hz, 2H), 4.23
– 3.92 (m, 1H), 2.44 (s, 3H), 1.39 (t, J = 7.1 Hz, 3H); 13C NMR (100
MHz, CDCl3) δ 195.99, 169.47, 144.33, 130.51, 128.74, 127.56, 75.23,
72.69, 61.03, 20.80, 12.92. HRMS(EI): calcd for C13H16O5Na [M+Na]+:
275.0895, found 275.0892; IR: v=3346.10, 1743.20, 1623.67, 1597.79,
1449.46, 1383.97, 1098.03, 767.01, 695.28 cm-1
ethyl (2R, 3R)-2,3-dihydroxy-4-(2-methoxyphenyl)-4-oxobutanoate
(syn-3e): Yield: 43%, 23.0 mg; white solid, m.p.= 84-86℃; [α]2D5 = -17.8
(c 0.294, in CHCl3); 98% ee, determined by HPLC analysis (Chiralpak
OD-H column, hexane/i-PrOH = 19:1, flow rate = 1.0 mL/min, λ=254 nm,
tmajor = 42.20 min, tminor = 46.55 min). 1H NMR (400 MHz, CDCl3) δ 7.97
(dd, J = 7.8, 1.8 Hz, 1H), 7.57 (ddd, J = 8.4, 7.4, 1.8 Hz, 1H), 7.11 –
7.05 (m, 1H), 7.02 (d, J = 8.4 Hz, 1H), 5.51 (dd, J = 6.2, 1.3 Hz, 1H),
4.57 (d, J = 8.3 Hz, 1H), 4.41 – 4.29 (m, 2H), 4.18 (d, J = 6.2 Hz, 1H),
3.98 (s, 3H), 2.98 (d, J = 8.7 Hz, 1H), 1.38 (t, J = 7.2 Hz, 3H); 13C NMR
(100 MHz, CDCl3) δ 198.11, 172.12, 158.89, 135.39, 131.84, 123.01,
121.40, 111.62, 78.11, 71.07, 62.10, 55.36, 14.17. HRMS (EI): calcd for
C13H16O6Na [M+Na]+: 291.0845, found 291.0845; IR: v=3368.34,
1755.15, 1662.94, 1598.11, 1486.27, 1127.20, 1082.07, 770.05, 723.21
cm-1
ethyl (2S, 3R)-2,3-dihydroxy-4-oxo-4-(p-tolyl)butanoate (anti-3b):
Yield: 57%, 28.7 mg; white solid, m.p.= 72-74℃; [α]2D5 = -85 (c 0.146, in
CHCl3); 93% ee, determined by HPLC analysis (Chiralpak AS column,
hexane/i-PrOH = 4:1, flow rate = 1.0 mL/min, λ=254 nm, tmajor = 25.35
min, tmino r= 31.95 min). 1H NMR (400 MHz, CDCl3) δ 7.84 (d, J = 8.0 Hz,
2H), 7.32 (d, J = 8.0 Hz, 2H), 5.31 (s, 1H), 4.59 (d, J = 31.1 Hz, 1H),
4.22 – 3.90 (m, 2H), 3.68 – 3.25 (m, 1H), 2.44 (s, 3H), 1.17 (t, J = 7.1
Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 195.81, 170.57, 144.47, 129.60,
128.81, 127.69, 73.33, 71.48, 61.53, 20.81, 13.25. HRMS (EI): calcd for
C13H16O5Na [M+Na]+: 275.0895, found 275.0892; IR: v=3346.10,
1743.20, 1623.67, 1597.79, 1449.46, 1383.97, 1098.03, 767.01, 695.28
cm-1
ethyl (2S, 3R)-2,3-dihydroxy-4-(2-methoxyphenyl)-4-oxobutanoate
(anti-3e): Yield: 55%, 29.4 mg; colorless oil; [α]2D5 = -88.2 (c 0.304, in
CHCl3); 94% ee, determined by HPLC analysis (Chiralpak OD-H
column, hexane/i-PrOH = 9:1, flow rate = 1.0 mL/min, λ = 254 nm, tmajor
= 15.60 min, tminor = 19.99 min). 1H NMR (400 MHz, CDCl3) δ 7.83 (dd, J
= 7.8, 1.7 Hz, 1H), 7.61 – 7.50 (m, 1H), 7.08 (t, J = 7.5 Hz, 1H), 7.02 (d,
J = 8.4 Hz, 1H), 5.39 (d, J = 1.8 Hz, 1H), 4.58 (d, J = 2.0 Hz, 1H), 4.17
– 4.00 (m, 3H), 3.97 (s, 3H), 1.17 (t, J = 7.1 Hz, 3H); 13C NMR (100
MHz, CDCl3) δ 198.13, 170.99, 158.53, 135.00, 131.58, 124.13, 121.17,
111.66, 80.03, 73.14, 61.83, 55.70, 13.90. HRMS (EI): calcd for
C13H16O6Na [M+Na]+: 291.0845, found 291.0845; IR: v=3368.34,
1755.15, 1662.94, 1598.11, 1486.27, 1127.20, 1082.07, 770.05, 723.21
cm-1
ethyl (2R, 3R)-2,3-dihydroxy-4-(4-methoxyphenyl)-4-oxobutanoate
(syn-3c): Yield: 41%, 21.9 mg; colorless oil; [α]2D5 = +30.0 (c 0.199, in
CHCl3); 96% ee, determined by HPLC analysis (Chiralpak OD-H
column, hexane/i-PrOH = 19:1, flow rate = 1.0 mL/min, λ = 254 nm,
tmajor = 44.25 min, tminor = 51.25 min). 1H NMR (400 MHz, CDCl3) δ 7.98
(d, J = 8.9 Hz, 1H), 7.01 (d, J = 8.9 Hz, 1H), 5.39 (dd, J = 6.8, 1.5 Hz,
1H), 4.58 – 4.52 (m, 1H), 4.37 (q, J = 7.1 Hz, 1H), 4.14 (d, J = 6.8 Hz,
1H), 3.89 (s, 1H), 3.06 (d, J = 7.9 Hz, 1H), 1.39 (t, J = 7.1 Hz, 2H);13C
NMR (100 MHz, CDCl3) δ 195.37, 171.54, 164.42, 130.92, 125.77,
114.31, 73.91, 72.54, 62.45, 55.55, 14.18. HRMS (EI): calcd for
C13H16O6Na [M+Na]+:291.0845, found 291.0844; IR: v=3415.26,
1744.38, 1574.08, 1513.36, 1463.03,1176.42, 1114.37, 789.54 cm-1
ethyl (2S, 3R)-2,3-dihydroxy-4-(4-methoxyphenyl)-4-oxobutanoate
(anti-3c): Yield: 53%, 28.4 mg; white solid, m.p.= 60-62℃; [α]2D5 = -22.0
(c 0.110, in CHCl3); 87% ee, determined by HPLC analysis (Chiralpak
AS column, hexane/i-PrOH = 4:1, flow rate = 1.0 mL/min, λ = 254 nm,
tmajor = 36.65 min, tminor = 45.79 min). 1H NMR (400 MHz, CDCl3) δ 8.14
– 7.71 (m, 2H), 7.19 – 6.67 (m, 2H), 5.29 (s, 1H), 4.63 (s, 1H), 4.28 –
3.97 (m, 2H), 3.90 (s, 3H), 1.18 (t, J = 8.0 Hz, 3H); 13C NMR (100 MHz,
CDCl3) δ 195.54, 170.44, 164.31, 130.77, 126.72, 114.23, 75.48, 73.71,
61.90, 55.54, 13.85. HRMS (EI): calcd for C13H16O6Na
[M+Na]+:291.0845, found 291.0844; IR: v=3415.26, 1744.38, 1574.08,
1513.36, 1463.03,1176.42, 1114.37, 789.54 cm-1
ethyl
(2R,
3R)-4-(2,5-dimethoxyphenyl)-2,3-dihydroxy-4-
oxobutanoate (syn-3f): Yield: 33%, 19.6 mg; pale-yellow solid, m.p.=
98-100℃; [α]2D5 = +3.0 (c 0.288, in CHCl3); 98% ee, determined by
HPLC analysis (Chiralpak AD column, hexane/i-PrOH = 4:1, flow rate =
1
1.0 mL/min, λ = 254 nm, tmajor = 23.70 min, tminor = 33.91 min). H NMR
(400 MHz, CDCl3) δ 7.49 (d, J = 3.2 Hz, 1H), 7.14 (dd, J = 9.1, 3.2 Hz,
1H), 6.96 (d, J = 9.1 Hz, 1H), 5.53 (dd, J = 6.4, 1.2 Hz, 1H), 4.58 (t, J =
16.4 Hz, 1H), 4.36 (q, J = 7.2 Hz, 2H), 4.15 (t, J = 12.1 Hz, 1H), 3.94 (s,
3H), 3.82 (s, 3H), 3.01 (d, J = 8.6 Hz, 1H), 1.38 (t, J = 7.1 Hz, 3H); 13
NMR (100 MHz, CDCl3) δ 199.09, 173.54, 155.22, 154.86, 124.18,
C
115.66, 114.47, 79.46, 72.46, 63.52, 57.15, 57.10, 15.56. HRMS (EI):
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