Sugiura et al.
941
Scheme 3. Chair-like transition state models for 2-aza Cope rearrangement.
NH2
NH2
CO H
2
HCOCO H
Me
–HCOCO H
2
2
N
HO C
HO C
2
2
HO C
2
Me
Me
syn-4c
(Z)-4c'
TS-syn
CO H
2
NH2
NH2
HCOCO H
N
–HCOCO H
2
2
Me
HO C
HO C
2
HO C
2
2
Me
anti-4c
Me
(E)-4c'
TS-anti
General procedure for allylation of hydroxyglycine
Under an argon atmosphere, to a suspension of hydroxy-
glycine (1) (45.5 mg, 0.5 mmol) in dry methanol (2 mL),
were added allylboronate 3 (1.2–2.0 equiv.) and triethylamine
2-Aminohex-4-enoic acid (4c′)
1
H NMR (400 MHz) (E-isomer) δ: 5.74 (dqt, J = 15.1,
6.4, 1.4 Hz, 1H), 5.38 (dtq, J = 15.1, 7.3, 1.8 Hz, 1H), 3.83
(dd, J = 6.7, 5.3 Hz, 1H), 2.67–2.49 (m, 2H), 1.67 (d, J =
6.4 Hz, 3H); (Z-isomer, a representative signal) δ: 1.63 (d,
J = 6.9 Hz, 3H).
(
0.1–2.0 equiv.) successively at ambient temperature. The
mixture was stirred at that temperature for the indicated
time, diluted with water, and charged on a cationic ion ex-
change resin column (Dowex 50W-X2, 50–100 mesh, H+
form; ca. 5 g/wet) with water. After washing with a suffi-
cient amount of water, α-amino acid 4 was eluted with
anti-2-Amino-3-phenylpent-4-enoic acid (4d) and (E)-2-
amino-5-phenylpent-4-enoic acid (4d′) (4d:4d′ = 93:7)
1
mp 172–176 °C. H NMR (400 MHz) δ: 7.52–7.28 (m,
1
0
.0 mol/L aqueous ammonia (fractions were checked by
.1 wt% ninhydrine in acetone–water (4:1)), and concen-
5.00H), 6.65 (d, J = 15.6 Hz, 0.07H), 6.29–6.14 (m, 1.00H),
5.36 (d, J = 17.4 Hz, 0.93H), 5.34 (d, J = 10.1 Hz, 0.93H),
3.98 (d, J = 7.8 Hz, 0.93H), 3.91–3.83 (m, 1.00H), 2.89–
trated to dryness.
1
3
2
1
4
1
1
.71 (m, 0.14H). For 4d: C NMR (150 MHz) δ: 173.6,
39.2, 135.3, 129.8, 128.54, 128.47, 120.6, 60.0, 51.8; for
d′: (distinguishable signals) δ: 174.7, 137.2, 129.5, 127.0,
23.6, 54.9, 34.7. HR-ESI-MS calcd. for C H NO :
Physical data of allylglycines
1
1
14
2
2
-Aminopent-4-enoic acid (4a)
+
92.1019 (M + H ); found: 192.1021.
See ref. 2.
syn-Aminocyclohex-2-enyl-acetic acid (4e)
2
-Amino-4-methylpent-4-enoic acid (4b)
1
mp 233–236 °C. H NMR (400 MHz) δ: 6.07–5.96 (m,
H), 5.54 (d, J = 10.1 Hz, 1H), 3.78 (d, J = 4.1 Hz, 1H),
.94–2.80 (m, 1H), 2.08–1.90 (m, 2H), 1.85–1.74 (m, 1H),
.72–1.61 (m, 1H), 1.60–1.46 (m, 1H), 1.40–1.25 (m, 1H).
C NMR (100 MHz) δ: 174.4, 133.7, 126.1, 58.9, 37.1,
4.8, 23.2, 21.6. HR-ESI-MS calcd. for C H NO :
1
mp 228–231 °C. H NMR (400 MHz) δ: 5.00 (s, 1H),
1
2
1
4
1
3
3
.90 (s, 1H), 3.85 (dd, J = 9.6, 4.6 Hz, 1H), 2.68 (dd, J =
4.7, 4.6 Hz, 1H), 2.50 (dd, J = 14.7, 9.6 Hz, 1H), 1.77 (s,
1
3
H). C NMR (100 MHz) δ: 175.2, 140.7, 116.0, 53.2,
13
9.7, 21.3. HR-ESI-MS calcd. for C H NO : 130.0863
6
12
2
2
1
+
8
14
2
(
M + H ); found: 130.0867.
+
56.1019 (M + H ); found: 156.1015.
syn-2-Amino-3-methylpent-4-enoic acid (syn-4c)
2
-Amino-3,3-dimethylpent-4-enoic acid (4f)
mp 212–216 °C. H NMR (400 MHz) δ: 5.86 (dd, J =
7.4, 11.0 Hz, 1H), 5.24 (d, J = 11.0 Hz, 1H), 5.21 (d, J =
1
mp 224–227 °C. H NMR (400 MHz) δ: 5.84 (ddd, J =
7.9, 10.1, 6.4 Hz, 1H), 5.26 (d, J = 10.1 Hz, 1H), 5.25 (d,
1
1
1
1
J = 17.9 Hz, 1H), 3.76 (d, J = 4.1 Hz, 1H), 2.94–2.82 (m,
13
7.4 Hz, 1H), 3.52 (s, 1H), 1.21 (s, 3H), 1.14 (s, 3H).
C
1
1
H), 1.10 (d, J = 6.9 Hz, 3H). 13C NMR (100 MHz) δ:
NMR (100 MHz) δ: 173.4, 143.0, 116.0, 62.9, 38.8, 25.0,
2
74.0, 138.2, 118.2, 59.0, 38.4, 13.6. HR-ESI-MS calcd. for
+
2.0. HR-ESI-MS calcd. for C H NO : 144.1019 (M + H );
7 14 2
+
C H NO : 130.0863 (M + H ); found: 130.0866.
6
12
2
found: 144.1020 (checked as an 85:15 mixture of 4f and
4
f′).
anti-2-Amino-3-methylpent-4-enoic acid (anti-4c)
1
mp 220–223 °C. H NMR (400 MHz) δ: 5.75 (ddd, J =
7.4, 10.1, 7.3 Hz, 1H), 5.25 (d, J = 17.4 Hz, 1H), 5.24 (d,
2-Amino-5-methylhex-4-enoic acid (4f′)
1
1
mp 198–202 °C. H NMR (400 MHz) δ: 5.10 (t, J =
J = 10.1 Hz, 1H), 3.61 (d, J = 5.5 Hz, 1H), 2.87–2.74 (m,
7.8 Hz, 1H), 3.74 (t, J = 6.0 Hz, 1H), 2.68–2.50 (m, 2H),
1.74 (s, 3H), 1.65 (s, 3H). C NMR (100 MHz) δ: 175.1,
139.6, 116.7, 55.3, 29.7, 25.7, 17.7. HR-ESI-MS calcd. for
H), 1.16 (d, J = 7.3 Hz, 3H). 13C NMR (100 MHz) δ:
13
1
1
74.4, 137.3, 118.8, 59.8, 39.1, 16.0. HR-ESI-MS calcd. for
+
+
C H NO : 130.0863 (M + H ); found: 130.0862.
C H NO : 144.1019 (M + H ); found: 144.1021.
6
12
2
7
14
2
©
2005 NRC Canada