The Journal of Organic Chemistry
Page 6 of 11
C; [lit. for the racemate 102 – 103 C]17; [α]D25 = +32.4 (c =
0.75, CHCl3); H NMR (400 MHz, CDCl3) δ ppm 7.34 (d,
Hz, 2 H, ArH), 5.62 (d, J=7.5 Hz, 1 H, CHNH), 5.35 (br. s., 1
H, NHCH), 4.21 (q, J=7.2 Hz, 2 H, CH2CH3), 2.33 (s, 3 H,
ArCH3), 1.45 (s, 9 H, OC(CH3)3), 1.25 (t, J=7.1 Hz, 3 H,
CH2CH3); 13C {1H} NMR 166.1 (OC=O), 155.0 (NC(=O)OC),
137.9 (ArC), 136.3 (ArC), 129.7 (ArCH), 126.2 (ArCH), 80.3
(OC(CH3)3), 61.1 (CH2CH3), 50.9 (CHNH), 28.5
(OC(CH3)3), 21.2 (ArCH3), 14.6 (CH2CH3); IR max/cm-1
3353, 2978, 2093, 1697, 1512, 1392, 1167. HRMS (ESI-TOF):
calcd for [M+Na]+ C17H23N3O4Na 356.1581 found 356.1581.
Data is consistent with that given in the literature.12
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J=8.5 Hz, 2 H, ArH), 7.30 (d, J=8.5 Hz, 2 H, ArH), 5.63 (d,
J=7.7 Hz, 1 H, CHNH), 5.42 (br. s., 1 H, NHCH), 4.13 - 4.33
(m, 2 H, CH2CH3), 1.45 (s, 9 H, OC(CH3)3), 1.25 (t, J=7.1 Hz,
3 H, CH2CH3); 13C {1H} NMR (101 MHz, CDCl3) δ ppm
165.9 (OC=O), 155.0 (NC(=O)OC), 137.9 (ArC), 134.0
(ArC), 129.2 (ArCH), 127.8 (ArCH), 80.7 (OC(CH3)3), 61.3
(CH3CH2), 51.0 (CHNH), 28.4 (OC(CH3)3), 14.5 (CH2CH3);
IR max/cm-1 3343, 2876, 2931, 2095, 1695, 1491, 1392, 1166;
HRMS (ESI-TOF) : calcd for [M+Na]+ C16H20ClN3O4Na
376.1035, found 376.1036. Data is consistent with that
given in the literature.12
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Ethyl (3R)-3-{[(tert-butoxy)carbonyl]amino}-2-diazo-
3-(2-methoxyphenyl)propanoate 4d Prepared according
to the general procedure A using aldimine 2d (23.5 mg,
0.10 mmol) to afford the title compound in 86% isolated
yield as a yellow oil (30 mg) and 96% ee [determined by
HPLC, Chiralpak AD-H, hexane/isopropanol = 95/5,
1 mL/min, = 220 nm, t (major) = 16.29 min, t (minor) =
Ethyl
(3R)-3-{[(tert-butoxy)carbonyl]amino}-3-(2-
4g Prepared
chlorophenyl)-2-diazopropanoate
according to general procedure A using aldimine 2g (23.9
mg, 0.10 mmol) to afford the title compound in 80%
isolated yield (28 mg) and 94% ee [determined by HPLC,
Chiralpak AD-H, hexane/isopropanol = 95/5, 1 mL/min,
= 220 nm, t (major) = 16.74 min, t (minor) = 19.41 min].
[α]D25 = +104.9 (c =1.0, CHCl3); 1H NMR (400 MHz, CDCl3)
δ ppm 7.47 (d, J=7.3 Hz, 1 H, ArH), 7.38 (dd, J=7.6, 1.4 Hz, 1
H, ArH), 7.21 - 7.32 (m, 2 H, ArH), 5.94 (d, J=7.7 Hz, 1 H,
CHNH), 5.74 (br. s, 1 H, NHCH), 4.01 - 4.37 (m, 2 H,
CH2CH3), 1.44 (s, 9 H, C(CH3)3), 1.23 (t, J=7.1 Hz, 3 H,
CH2CH3);13C {1H} NMR (101 MHz, CDCl3) δ ppm 166.0
(OC=O), 154.8 (NC(=O)OC), 136.8 (ArC), 132.8 (ArC), 130.1
(ArCH), 129.2 (ArCH), 128.2 (ArCH), 127.1 (ArCH), 80.5
25
19.79 min]. [α]D = +4.5 (c =1.2, CHCl3). 1H-NMR
(400 MHz, CDCl3) δ ppm 7.23 - 7.37 (m, 2 H, ArH), 6.88 -
6.98 (m, 2 H, ArH), 5.83 (br. s., 2 H, CHNH& NHCH), 4.17
(q, J=7.1 Hz, 2 H, CH2CH3), 3.87 (s, 3 H, ArOCH3), 1.46 (s, 9
H, OC(CH3)3), 1.23 (t, J=7.1 Hz, 3 H, CH2CH3); 13C {1H}
NMR (101 MHz, CDCl3) δ 166.3 (OC=O), 156.8 (ArC), 154.8
(NC(=O)OC)), 129.2 (ArCH), 128.4 (ArCH), 127.4 (ArC),
120.8 (ArCH), 110.7 (ArCH), 80.2 (OC(CH3)3), 60.9
(CH3CH2), 55.4 (ArOCH3), 47.8 (CHNH), 28.4 (OC(CH3)3),
14.5 (CH2CH3); IR max/cm-1 3353, 2976, 2093, 1695, 1602,
1491, 1392, 1165. HRMS (ESI-TOF): calcd for [M+Na]+ for
C17H23N3O5Na 372.1530, found 372.1527.
(OC(CH3)3), 61.3 (CH2CH3), 49.34 (CHNH),
28.59
(OC(CH3)3), 14.65 (CH2CH3); IR max/cm-1 3343, 2977, 2360,
2096, 1698, 1476, 1169. HRMS (ESI-TOF): calcd for
[M+Na]+ C16H20ClN3O4Na 376.1035, found 376.1036.
Ethyl (3R)-3-{[(tert-butoxy)carbonyl]amino}-2-diazo-
3-(4-methoxyphenyl)propanoate 4e Prepared according
to the general procedure A using aldimine 2e (23.5 mg,
0.10 mmol) to afford the title compound in 80% isolated
yield as a yellow solid (28 mg) and 98% ee [determined by
HPLC, Chiralpak AD-H, hexane/isopropanol = 95/5, 1
mL/min, λ = 220 nm, t (major) = 25.17, t (minor) = 27.78
min]. MPT 68 – 70 C; [lit. for the racemate 97 – 98 C]12;
Ethyl (3R)-3-{[(tert-butoxy)carbonyl]amino}-2-diazo-
3-(4-fluorophenyl)propanoate 4h Prepared according to
general procedure A, using aldimine 2h (22.3 mg,
0.10 mmol) which afforded the title compound in 76%
isolated yield as a yellow solid (25 mg) and 96% ee.
1
[α]D25 = +12.3 (c = 1.3, CHCl3). H-NMR (400 MHz, CDCl3)
[determined
by
HPLC,
Chiralpak
AD-H,
δ ppm 7.28 (d, J = 8.6 Hz, 2H, ArH), 6.90 (d, J=8.6 Hz, 2H,
ArH), 5.62 (d, J=7.3 Hz, 1H, CHNH), 5.32 (br.s, 1H,
NHCH), 4.25 (q, J = 7.1 Hz, 2H, CH2CH3), 3.80 (s, 3H,
ArOCH3), 1.45 (s, 9H, (OC(CH3)3), 1.27 (t, J=7.1 Hz, 3H,
CH2CH3); 13C {1H} NMR (101 MHz, CDCl3) δ ppm 166.0
(OC=O), 159.3 (ArCOMe), 154.8 (NC(=O)OC), 131.2 (ArC),
127.4 (ArCH), 114.2 (ArCH), 80.3 (OC(CH3)3), 61.0
(CH2CH3), 55.3 (ArOCH3), 50.7 (CHNH), 28.3 (OC(CH3)3),
14.4 (CH2CH3); IR max/cm-1 3352, 2978, 2092, 1692, 1511,
1162; HRMS (ESI-TOF) : calcd for [M+Na]+ C17H23N3O5Na
372.1530, found 372.1532. Data is consistent with that given
in the literature.12
hexane/isopropanol = 95/5, 1 mL/min, = 220 nm, t
(major) = 15.31 min, t (minor) = 17.15 min]. MPT 82 –
25
1
86 C; [α]D = +29.5 (c =1.1, CHCl3). H NMR (400 MHz,
CDCl3) δ ppm 7.31-7.34 (m, 2 H, ArH), 7.02-7.06 (m, 2 H,
ArH), 5.64 (d, J=7.4 Hz, 1 H, CHNH), 5.41 (br. s, 1 H,
NHCH), 4.22 (q, J=7.1 Hz, 2 H, CH2CH3), 1.45 (s, 9 H,
OC(CH3)3), 1.25 (t, J=7.1 Hz, 3 H, CH2CH3); 13C {1H} NMR
(101 MHz, CDCl3) δ ppm 165.8 (OC=O), 163.6 & 161.1 (d, JCF
= 247.2 Hz, ArCF), 154.9 (NC(=O)OC), 134.9 (ArC), 127.9
(ArCH), 127.9 (ArCH), 115.8 (ArCH), 115.6 (ArCH), 80.5
(OC(CH3)3), 61.1 (CH2CH3), 50.8 (CHNH), 28.3
(OC(CH3)3), 14.4 (CH2CH3); 19F NMR δ -114.3; IR max/cm-1
3346, 2980, 2095, 1694, 1509, 1158. Data is consistent with
that given in the literature.12
Ethyl
(3R)-3-{[(tert-butoxy)carbonyl]amino}-3-(4-
4f Prepared
chlorophenyl)-2-diazopropanoate
according to general procedure A using aldimine 2f
(23.9 mg, 0.10 mmol) to afford the title compound in 60%
isolated yield as a yellow solid (19 mg) and 96% ee.
Ethyl
(3R)-3-(3-bromophenyl)-3-{[(tert-
4i
butoxy)carbonyl]amino}-2-diazopropanoate
Prepared according to the general procedure A using
aldimine 2i (28.4 mg, 0.10 mmol) to afford the title
compound as a yellow oil in 72% isolated yield (28 mg)
and 95% ee [determined by HPLC, Chiralpak AS-H,
[determined
by
HPLC,
Chiralpak
AD-H,
hexane/isopropanol = 95/5, 1 mL/min, = 220 nm, t
(major) = 15.42 min, t (minor) = 17.49 min]. MPT 88-92
6
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