Catalytic Preparation of Aziridines with an Iron Lewis Acid
J . Org. Chem., Vol. 63, No. 20, 1998 6843
mmol) to 5 mL with CH2Cl2 and then was reacted with a
solution of 1 (67.4 mg, 0.201 mmol) and 2a (371 mg, 2.01 mmol)
in 3 mL of CH2Cl2, providing 150 mg of cis-aziridine, a 40%
isolated yield: 1H NMR (CDCl3) δ 7.54-7.49 (m, 2H), 7.40-
7.25 (m, 5H), 7.08-7.03 (m, 3H), 4.10-3.95 (m, 2H), 3.62-
3.55 (d, J ) 6.75 Hz, 1H), 3.23-3.18 (d, J ) 6.75 Hz, 1H),
1.03-0.95 (t, J ) 7.12 Hz, 3H). In addition, 6a and 7a were
formed and isolated as a mixture (114 mg, 21% yield) in a 5:1
ratio. For 6a :13 1H NMR (CDCl3) δ 10.37-10.31 (bd, J ) 12.75
Hz, 1H), 7.45-7.39 (d, J ) 12.75 Hz, 1H), 7.37-7.22 (m, 7H),
7.04-6.96 (m, 3H), 4.31-4.19 (q, J ) 7.0 Hz, 2H), 1.35-1.27
(t, J ) 7.0 Hz, 3H). For 7a :13 1H NMR (CDCl3) δ 10.31 (bs,
1H), 7.40-6.60 (m, 10H), 4.99 (s, 1H), 4.22-4.10 (q, J ) 7.0
Hz, 2H), 1.28-1.20 (t, J ) 7.0 Hz, 3H).
cis-(2-(4-Ch lor op h en yl)-3-et h oxyca r b on yl)-1-p h en yl-
a zir id in e (4d ).12a An EDA solution was prepared by diluting
EDA (0.15 mL, 1.32 mmol) to 5 mL with CH2Cl2 and then was
reacted with a solution of 1 (35.5 mg, 0.106 mmol) and 2d (228
mg, 1.06 mmol) in 5 mL of CH2Cl2, providing 160 mg of cis-
aziridine, a 50% isolated yield: 1H NMR (CDCl3) δ 7.49-7.40
(m, 2H), 7.35-7.20 (m, 4H), 7.08-6.99 (m, 3H), 4.11-3.90 (m,
2H), 3.55-3.50 (d, J ) 6.7 Hz, 1H), 3.21-3.16 (d, J ) 6.7 Hz,
1H), 1.09-0.99 (t, J ) 7.1 Hz, 3H). In addition, 6d and 7d 24
were formed and isolated as a mixture (70 mg, 22% yield) in
a 5:1 ratio. For 6d : 1H NMR (CDCl3) δ 10.38-10.33 (bd, J )
12.75 Hz, 1H), 7.40-6.95 (m, 10H), 4.30-4.19 (q, J ) 7.0 Hz,
2H), 1.34-1.24 (t, J ) 7.0 Hz, 3H).
Hz, 1H), 1.07-1.01 (t, J ) 7.14 Hz, 3H); 13C NMR (CDCl3) δ
167.5, (d, 164.5, 160.6), 152.2, 130.5, (d, 129.5, 129.4), 129.3,
123.6, 119.9, (d, 115.2, 114.9), 61.1, 46.5, 45.6, 14.0. MS (70
eV) m/z: 285 (11), [M+]; 256 (11), [M+ - Et]; 240 (23), [M+
-
OEt]; 212 (100), [M+ - CO2Et]; 193 (30), [M+ - NHPh or -
CO2Et, - F]; 104 (72), [M+ - CO2Et, - CHPhF]. Anal. Calcd
for C17H16FNO2: C, 71.56; H, 5.65; N, 4.91. Found: C, 71.52;
H, 5.63; N, 4.81. In addition, 6f and 7f24 were formed and
isolated as a mixture (45 mg, 14% yield) in a 10:1 ratio. For
6f: 1H NMR (CDCl3) δ 10.34-10.28 (bd, J ) 12.75 Hz, 1H),
7.40-7.34 (d, J ) 12.75 Hz, 1H), 7.40-7.21 (m, 4H), 7.10-
6.90 (m, 5H), 4.29-4.19 (q, J ) 7.0 Hz, 2H), 1.34-1.24 (t, J )
7.0 Hz, 3H).
cis-(2-Eth oxyca r bon yl-3-(4-tr iflu or om eth ylp h en yl))-1-
p h en yla zir id in e (4g).25 An EDA solution was prepared by
diluting EDA (0.22 mL, 1.87 mmol) to 5 mL with CH2Cl2 and
then was reacted with a solution of 1 (50.2 mg, 0.149 mmol)
and 2g (372 mg, 1.49 mmol) in 5 mL of CH2Cl2, providing 267
mg of cis-aziridine, a 53% isolated yield, obtained as an off-
white crystalline compound: mp ) 87.5-89 °C; 1H NMR
(CDCl3) δ 7.68-7.55 (m, 4H), 7.33-7.20 (m, 2H), 7.10-7.00
(m, 3H), 4.13-3.90 (m, 2H), 3.63-3.60 (d, J ) 6.73 Hz, 1H),
3.26-3.23 (d, J ) 6.75 Hz, 1H), 1.05-0.98 (t, J ) 7.12 Hz,
3H); 13C NMR (CDCl3) δ 167.2, 152.0, 138.9, 129.3, 128.2,
123.8, 119.9, 61.2, 46.5, 45.7, 13.9, [130.7, 126.3, 122.0, 117.7,
q, 1J (C,F) ) 1080 Hz, CF3], [131.0, 130.5, 130.0, 129.5, q,
2J (C,F) ) 128 Hz], [125.1, 125.0, 124.9, m]. MS (70 eV) m/z:
335 (8), [M+]; 290 (9), [M+ - OEt]; 262 (63), [M+ - CO2Et];
243 (11), [M+ - NHPh]; 104 (100), [M+ - CO2Et, - CHPhCF3].
Anal. Calcd for C18H16F3NO2: C, 64.47; H, 4.81; N, 4.18.
Found: C, 64.34; H, 4.75; N, 4.06. In addition, 6g and 7g24
were formed and isolated as a mixture (100 mg, 20% yield) in
a 4:1 ratio. For 6g: 1H NMR (CDCl3) δ 10.50-10.45 (bd, J )
12.75 Hz, 1H), 7.70-7.00 (m, 10H), 4.34-4.22 (q, J ) 7.0 Hz,
2H), 1.35-1.30 (t, J ) 7.0 Hz, 3H).
2-E t h oxyca r b on yl-3-(4-n it r op h e n yl)-1-p h e n yla zir i-
d in e (4h ).13 An EDA solution was created by diluting EDA
(0.18 mL, 1.51 mmol) to 4 mL with CH2Cl2 and then was
reacted with a solution of 1 (25.4 mg, 0.076 mmol) and 2h (171
mg, 0.76 mmol) in 4 mL of CH2Cl2, providing an isolated
mixture of cis- and trans-aziridines in a 4:1 ratio and 78%
overall yield (182 mg), based upon the imine. For the cis
isomer: 1H NMR (CDCl3) δ 8.23-8.16 (d, J ) 8.9 Hz, 2H),
7.73-7.66 (d, J ) 8.9 Hz, 2H), 7.32-7.21 (m, 2H), 7.10-6.98
(m, 3H), 4.13-3.95 (m, 2H), 3.66-3.62 (d, J ) 6.7 Hz, 1H),
3.30-3.26 (d, J ) 6.7 Hz, 1H), 1.08-1.00 (t, J ) 7.1 Hz, 3H).
For the trans isomer: 1H NMR (CDCl3) δ 8.23-8.19 (d, J )
8.8 Hz, 2H), 7.55-7.51 (d, J ) 8.8 Hz, 2H), 7.33-6.87 (m, 5H),
4.15-3.95 (m, 2H), 3.89-3.88 (d, J ) 2.3 Hz, 1H), 3.24-3.23
(d, J ) 2.3 Hz, 1H), 1.19-1.12 (t, J ) 7.15 Hz, 3H). In
addition, 6h and 7h were formed and isolated as a mixture
(52 mg, 22% yield) in a 3:1 ratio. For 6h :13 1H NMR (CDCl3)
δ 10.60-10.54 (bd, J ) 13.0 Hz, 1H), 8.20-8.14 (d, J ) 8.75
Hz, 2H), 7.55-7.50 (d, J ) 13.0 Hz, 1H), 7.52-7.48 (d, J )
8.75 Hz, 2H), 7.38-7.30 (m, 2H), 7.11-7.03 (m, 3H), 4.34-
4.25 (q, J ) 7.0 Hz, 2H), 1.36-1.28 (t, J ) 7.0 Hz, 3H). For
7h :13 1H NMR (CDCl3) δ 10.23 (bs, 1H), 8.15-8.11 (d, J ) 8.75
Hz, 2H), 7.53-7.49 (d, J ) 8.75 Hz, 2H), 7.13-7.07 (m, 2H),
6.98-6.90 (m, 1H), 6.67-6.63 (d, J ) 7.75 Hz, 2H), 5.03 (s,
1H), 4.27-4.17 (q, J ) 7.0 Hz, 2H), 1.35-1.29 (t, J ) 7.0 Hz,
3H).
2-(2,4-Dich lor oph en yl)-3-eth oxycar bon yl-1-ph en ylazir -
id in e (4e).25 An EDA solution was prepared by diluting EDA
(0.21 mL, 1.79 mmol) to 5 mL with CH2Cl2 and then was
reacted with a solution of 1 (48.1 mg, 0.143 mmol) and 2e (358
mg, 1.43 mmol) in 6 mL of CH2Cl2, providing 57 mg of cis-
and 126 mg of trans-aziridine, a 1:2.2 ratio and a 38% overall
isolated yield. Spectrometric and analytical data for the cis
isomer: 1H NMR (CDCl3) δ 7.72-7.67 (d, J ) 8.3 Hz, 1H),
7.38-7.22 (m, 4H), 7.11-7.00 (m, 3H), 4.15-3.95 (m, 2H),
3.71-3.67 (d, J ) 6.67 Hz, 1H), 3.32-3.28 (d, J ) 6.5 Hz, 1H),
1.10-1.01 (t, J ) 7.12 Hz, 3H); 13C NMR (CDCl3) δ 167.2,
152.0, 134.3, 134.2, 131.6, 131.3, 129.3, 128.6, 126.9, 123.8,
119.9, 61.2, 45.2, 45.0, 13.9. MS (15 eV) m/z: 337 (10), 335
(15), [M+]; 306 (10), [M+ - Et]; 300 (24), [M+ - Cl]; 292 (10),
290 (16), [M+ - OEt]; 266 (11), 264 (67), 262 (100), [M+ - CO2-
Et]; 245 (24), 243 (39), [M+ - NHPh]; 227 (27), [M+ - CO2Et,
- Cl]; 104 (61), [M+ - CO2Et, - CHPhCl2]. Anal. Calcd for
C
17H15Cl2NO2: C, 60.73; H, 4.50; N, 4.17. Found: C, 60.62;
H, 4.50; N, 3.91. Spectrometric data for the trans isomer: 1H
NMR (CDCl3) δ 7.43-6.90 (m, 8H), 4.19-4.00 (m, 2H), 4.06-
4.05 (d, J ) 2.3 Hz, 1H), 3.11-3.10 (d, J ) 2.5 Hz, 1H), 1.15-
1.09 (t, J ) 7.13 Hz, 3H). MS (70 eV) m/z: 337 (9), 335 (13),
[M+]; 300 (17), [M+ - Cl]; 292 (14), 290 (21), [M+ - OEt]; 266
(13), 264 (67), 262 (100), [M+ - CO2Et]; 245 (21), 243 (33), [M+
- NHPh]; 229 (27), 227 (72), [M+ - CO2Et, - Cl]; 104 (84),
[M+ - CO2Et, - CHPhCl2]. An analytically pure sample of
the trans isomer was not obtained; therefore the CHN analysis
was not accomplished. In addition, 6e and 7e24 were formed
and isolated as a mixture (102 mg, 21% yield) in a 4:1 ratio.
For 6e: 1H NMR (CDCl3) δ 10.32-10.26 (bd, J ) 12.5 Hz, 1H),
7.43-6.90 (m, 9H), 4.25-4.12 (q, J ) 7.0 Hz, 2H), 1.30-1.20
(t, J ) 7.0 Hz, 3H).
cis-(2-Eth oxycar bon yl-3-(4-flu or oph en yl))-1-ph en ylazir -
id in e (4f).25 An EDA solution was prepared by diluting EDA
(0.17 mL, 1.44 mmol) to 5 mL with CH2Cl2 and then was
reacted with a solution of 1 (38.7 mg, 0.115 mmol) and 2f (230
mg, 1.15 mmol) in 5 mL of CH2Cl2, providing 144 mg of cis-
aziridine, a 44% isolated yield: 1H NMR (CDCl3) δ 7.53-7.47
(m, 2H), 7.31-7.23 (m, 2H), 7.08-7.00 (m, 5H), 4.13-3.93 (m,
2H), 3.57-3.54 (d, J ) 6.70 Hz, 1H), 3.20-3.17 (d, J ) 6.68
cis-1,2,3-Tr ip h en yla zir id in e (5a ).26 A PDM solution was
prepared by diluting 2.6 M PDM (0.91 mL, 2.13 mmol) to 5
mL with CH2Cl2 and then was reacted with a solution of 1
(50.0 mg, 0.149 mmol) and 2a (275 mg, 1.49 mmol) in 5 mL of
CH2Cl2, providing 383 mg of cis-aziridine, a 95% isolated
yield: 1H NMR (CDCl3) δ 7.35-7.03 (m, 15H), 3.67 (s, 2H);
13C NMR (CDCl3) δ 154.7, 136.0, 129.2, 127.9 (2C), 127.0,
122.7, 119.9, 49.1.
(24) These compounds (7d , 7e, 7f, and 7g) were isolated as an
inseparable mixture along with 6d , 6e, 6f, and 6g, respectively, and
were the minor component of these fractions. In addition, their 1H NMR
peaks were mostly buried under the peaks for byproducts 6; therefore,
the 1H NMR peak assignments were not accomplished.
cis-2-(4-Meth ylp h en yl)-1,3-d ip h en yla zir id in e (5b).25
A
PDM solution was prepared by diluting 2.7 M PDM (1.05 mL,
2.55 mmol) to 5 mL with CH2Cl2 and then was reacted with a
(25) To our knowledge, these compounds are new and previously
unreported; therefore, they have been more thoroughly characterized.
(26) Matsumoto, K.; Nakamura, S. Heterocycles 1980, 14, 837-846.