6406 J . Org. Chem., Vol. 65, No. 20, 2000
Olivera et al.
1.1 Hz); 13C NMR (CDCl3) δ 41.0, 66.1, 100.2, 114.4, 127.8,
129.1, 130.2, 132.6, 135.1 (Carom-C), 140.2; FTIR (neat film,
cm-1): 2216; EIMS (m/z, %) 286 (M+, 24). Anal. Calcd for
C10H11IN2: C, 41.98; H, 3.88; N, 9.79. Found: C, 42.09; H, 3.96;
N, 9.86.
2-(N,N-Dim eth ylam in o)-2-(4,5-dim eth oxy-2-iodoph en yl)-
a cet on it r ile (7d ) (89%), as a white powder; mp 76-77 °C
(MeOH); Rf 0.36 (25% EtOAc/hexane); 1H NMR (CDCl3) δ 2.34
(6H, s), 3.88 (3H, s), 3.91 (3H, s), 4.81 (1H, s), 7.08 (1H, s),
7.30 (1H, s); 13C NMR (CDCl3) δ 41.2, 55.9, 56.0, 66.0, 88.5,
112.0, 115.0, 122.2, 128.0, 148.8, 149.4; FTIR (neat film, cm-1):
2224; EIMS (m/z, %) 346 (M+, 24), 302 (100), 176 (15). Anal.
Calcd for C12H15IN2O2: C, 41.64; H, 4.37; N, 8.09. Found: C,
41.84; H, 4.33; N, 8.22.
152.1; FTIR (neat film, cm-1): 1589; EIMS (m/z, %) 535 (M+,
22), 408 (74). Anal. Calcd for C18H19I2NO2: C, 40.40; H, 3.58;
N, 2.62. Found: C, 40.72; H, 3.51; N, 2.81.
(E)-1,2-Bis(2-br om o-4,5-dim eth oxyph en yl)-N,N-dim eth -
yleth en yla m in e (15c). Typ ica l P r oced u r e (Meth od B). A
solution of R-aminonitrile 7c (6.8 g, 22.7 mmol) in dry degassed
DMF (17 mL) was added dropwise to a stirred suspension of
NaH (95%, 1.26 g, 50.0 mmol) in dry degassed DMF (13 mL)
under argon at -19 °C. After the mixture was stirred for 1 h
at the same temperature, a solution of arylmethyl bromide 17c
(12.7 g, 40.9 mmol) in dry degassed DMF (22 mL) was added,
and the reaction mixture was stirred for 15 min at -19 °C,
warmed to room temperature, and stirred for an additional
1.5 h. Water (∼10 mL) was slowly added until bubbling
stopped, and the solvent was evaporated in vacuo (1 mmHg,
T ∼ 90 °C). The residue was purified by flash chromatography
using 30% EtOAc/hexane as eluent to afford enamine 15c (8.98
g, 79%) as a white powder: mp 138-140 °C (MeOH); Rf 0.57
(40% hexane/EtOAc); 1H NMR (CDCl3) δ 2.74 (6H, s), 3.37 (3H,
s), 3.73 (3H, s), 3.77 (3H, s), 3.84 (3H, s), 5.49 (1H, s), 6.18
(1H, s), 6.70 (1H, s), 6.90 (1H, s), 6.97 (1H, s); 13C NMR (CDCl3)
δ 39.5, 54.6, 55.4, 55.6, 55.7, 101.5, 111.5, 113.0, 113.9, 114.2,
114.3, 114.9, 129.8, 130.6, 145.7, 146.8, 148.2, 148.7; FTIR
(neat film, cm-1): 1595; EIMS (m/z, %) 503 (M + 2, 52), 501
(M+, 100), 499 (M - 2, 50). Anal. Calcd for C20H23Br2NO4: C,
47.93; H, 4.62; N, 2.79. Found: C, 48.09; H, 4.71; N, 2.54.
The same procedure on R-aminonitrile 7d and bromide 17d
provided (E)-1,2-bis(4,5-dimethoxy-2-iodophenyl)-N,N-dimeth-
ylethenylamine 15d (81%) as a yellow powder: mp 111-112
°C (50% acetone/MeOH); Rf 0.29 (40% EtOAc/hexane); 1H NMR
(CDCl3) δ 2.74 (6H, s), 3.37 (3H, s), 3.71 (3H, s), 3.76 (3H, s),
3.82 (3H, s), 5.38 (1H, s), 6.20 (1H, s), 6.67 (1H, s), 7.12 (1H,
s), 7.18 (1H, s); 13C NMR (CDCl3) δ 39.8, 55.0, 55.8, 55.9, 88.5,
89.1, 106.6, 112.0, 114.0, 120.4, 121.3, 134.1, 134.7, 146.0,
148.1, 148.8, 149.3, 151.5; FTIR (neat film, cm-1): 1598; EIMS
(m/z, %) 595 (M+, 4), 469 (100). Anal. Calcd for C20H23I2NO4:
C, 40.36; H, 3.89; N, 2.35. Found: C, 40.64; H, 3.77; N, 2.49.
The same procedure on R-aminonitrile 7a and bromide 17c
provided (E)-2-(2-bromo-4,5-dimethoxyphenyl)-1-(2-bromo-
phenyl)-N,N-dimethylethenylamine 15g (79%) as a yellow
oil: Rf 0.44 (30% EtOAc/hexane); 1H NMR (CDCl3) δ 2.70 (6H,
s, 3.25 (3H, s, 3.72 (3H, s, 5.51 (1H, s), 6.05 (1H, s), 6.87 (1H,
s), 7.05-7.19 (3H, m), 7.52 (1H, dd, J ) 7.7, 1.6 Hz); 13C NMR
(CDCl3) δ 40.0, 55.0, 55.8, 101.9, 111.9, 113.2, 114.7, 124.5,
127.6, 129.3, 122.0, 132.2, 132.8, 138.2, 145.6, 146.9, 148.9;
FTIR (neat film, cm-1): 1571; EIMS (m/z, %) 443 (M + 2, 51),
441 (M+, 100), 439 (M - 2, 52), 428 (18), 426 (35), 424 (21),
362 (68), 360 (78). Anal. Calcd for C18H19Br2NO2: C, 49.01; H,
4.34; N, 3.17. Found: C, 49.31; H, 4.36; N, 2.99.
The same procedure on R-aminonitrile 7b and bromide 17d
provided (E)-N,N-dimethyl-2-(4,5-dimethoxy-2-iodophenyl)-1-
(2-iodophenyl)ethenylamine 15h (78%) as a yellow oil: Rf 0.41
(30% EtOAc/hexane); 1H NMR (CDCl3) δ 2.74 (6H, s), 3.29 (3H,
s), 3.76 (3H, s), 5.42 (1H, s), 6.08 (1H, s), 6.95 (1H, ddd, J )
7.9, 7.9, 1.5 Hz), 7.11-7.17 (2H, m), 7.27 (1H, ddd, J ) 7.9,
7.9, 1.4 Hz), 7.83 (1H, dd, J ) 7.9, 1.5 Hz); 13C NMR (CDCl3)
δ 39.9, 55.0, 55.8, 88.9, 100.6, 106.8, 111.6, 120.5, 128.3, 129.2,
131.5, 134.1, 139.4, 141.9, 146.0, 148.0, 151.6; FTIR (neat film,
cm-1): 1598; EIMS (m/z, %) 535 (M+, 100), 520 (19), 408 (44).
Anal. Calcd for C18H19I2NO2: C, 40.40; H, 3.58; N, 2.62.
Found: C, 40.66; H, 3.49; N, 2.41.
The same procedure on R-aminonitrile 7a and bromide 17d
provided (E)-1-(2-bromophenyl)-N,N-dimethyl-2-(4,5-dimethoxy-
2-iodophenyl)ethenylamine 15i (71%) as an amber oil: Rf 0.47
(30% EtOAc/hexane); 1H NMR (CDCl3) δ 2.75 (6H, s), 3.31 (3H,
s), 3.76 (3H, s), 5.44 (1H, s), 6.14 (1H, s, 7.08-7.22 (4H, m),
7.54 (1H, dd, J ) 7.9, 1.6 Hz); 13C NMR (CDCl3) δ 40.0, 55.0,
55.8, 89.0, 107.0, 111.5, 120.6, 124.8, 127.5, 129.3, 132.2, 132.7,
134.5, 138.3, 146.1, 148.1, 149.2; FTIR (neat film, cm-1): 1586;
EIMS (m/z, %) 489 (M + 1, 33), 487 (M - 1, 34), 362 (17), 360
(23), 291 (100). Anal. Calcd for C18H19BrINO2: C, 44.29; H,
3.92; N, 2.87. Found: C, 44.64; H, 3.66; N, 2.95.
Syn th esis of Dia r ylen a m in es.
(E )-1,2-Bis(2-b r om op h e n yl)-N ,N -d im e t h yle t h e n yl-
a m in e (15a ). Typ ica l P r oced u r e (Meth od A). A solution
of 2-bromobenzyl chloride 8a (5.7 g, 27.6 mmol) in dry degassed
DMF (18 mL) was quickly added to a stirred suspension of
NaH (95%, 1.39 g, 55.0 mmol) in dry degassed DMF (15 mL)
under argon at -19 °C. A solution of R-aminonitrile 7a (6.0 g,
25.1 mmol) in dry DMF (6 mL) was immediately added to this
mixture, as the solution was turning red. After stirring for 15
min at the same temperature, the reaction mixture was
allowed to warm to room temperature and stirring was
continued for an additional 1.5 h. Water (∼30 mL) was added
until hydrogen bubbling stopped. Evaporation of the solvent
under reduced pressure (1 mmHg, T ∼90 °C) afforded a brown
oil which was purified by flash chromatography using 10%
EtOAc/hexane as eluent, providing enamine 15a (8.31 g, 87%)
as a white powder, mp 82-83 °C (EtOH); Rf 0.38 (30% CH2-
Cl2/hexane); 1H NMR (CDCl3) δ 2.76 (6H, s), 5.60 (1H, s), 6.45-
6.49 (1H, m), 6.71-6.75 (2H, m), 7.17-7.21 (3H, m), 7.40-
7.44 (1H, m), 7.55 (1H, d, J ) 7.5 Hz); 13C NMR (CDCl3) δ
40.0, 102.1, 123.9, 124.7, 125.1, 126.4, 127.5, 129.2, 129.5,
132.1, 132.2, 132.9, 138.0, 138.6, 150.0; FTIR (neat film, cm-1):
1584; EIMS (m/z, %) 383 (M + 2, 30), 381 (M+, 59), 379 (M -
2, 29), 302 (71), 300 (100). Anal. Calcd for C16H15Br2N: C,
50.42; H, 3.97; N, 3.68%). Found: C, 50.81; H, 3.74; N, 3.77.
The same procedure on R-aminonitrile 7b and chloride 8b
provided (E)-N,N-dimethyl-1,2-bis(2-iodophenyl)ethenylamine
15b (83%) as a white powder: mp 102-103 °C (Et2O); Rf 0.32
(30% CH2Cl2/hexane); 1H NMR (CDCl3) δ 2.76 (6H, s), 5.49
(1H, s), 6.47 (1H, dd, J ) 7.9, 1.3 Hz), 6.56 (1H, ddd, J ) 7.5,
7.5, 1.5 Hz), 6.78 (1H, ddd, J ) 7.9, 7.9, 0.9 Hz), 6.96 (1H,
ddd, J ) 7.9, 7.9, 1.3 Hz), 7.14 (1H, dd, J ) 7.5, 1.8 Hz), 7.23
(1H, ddd, J ) 7.5, 7.5, 1.5 Hz), 7.72 (1H, dd, J ) 7.9, 1.8 Hz),
7.82 (1H, dd, J 7.5, 1.8 Hz); 13C NMR (CDCl3) δ 40.0, 100.8,
101.8, 107.1, 125.3, 127.3, 128.2, 128.6, 129.3, 131.5, 138.6,
139.5, 141.4, 141.6, 152.4; FTIR (neat film, cm-1): 1596; EIMS
(m/z, %) 475 (M+, 100), 348 (65), 346 (23). Anal. Calcd for
C
16H15I2N: C, 40.45; H, 3.18; N, 2.95. Found: C, 40.59; H, 3.09;
N, 3.18.
The same procedure on R-aminonitrile 7c and chloride 8a
provided (E)-1-(2-bromo-4,5-dimethoxyphenyl)-2-(2-bromo-
phenyl)-N,N-dimethylethenylamine 15e (80%) as a red oil: Rf
0.45 (30% EtOAc/hexane); 1H NMR (CDCl3) δ 2.58 (6H, s), 3.88
(3H, s), 3.90 (3H, s), 5.57 (1H, s), 6.53 (1H, dd, J ) 7.5, 2.0
Hz), 6.69 (1H, s), 6.74 (1H, ddd, J ) 7.5, 7.5, 2.4 Hz), 6.80
(1H, ddd, J ) 7.5, 7.0, 2.0 Hz), 6.97 (1H, s), 7.43 (1H, dd, J )
7.0, 2.4 Hz); 13C NMR (CDCl3) δ 39.4, 55.3, 101.5, 113.6, 114.0,
114.8, 123.2, 124.5, 125.9, 128.4, 129.0, 131.4, 138.1, 147.9,
148.6, 149.3; FTIR (neat film, cm-1): 1594; EIMS (m/z, %) 443
(M + 2, 46), 441 (M+, 92), 439 (M - 2, 47), 362 (92), 360 (100).
Anal. Calcd for C18H19Br2NO2: C, 49.01; H, 4.34; N, 3.17.
Found: C, 49.37; H, 4.31; N, 2.94.
The same procedure on R-aminonitrile 7d and chloride 8b
provided (E)-1-(4,5-dimethoxy-2-iodophenyl)-N,N-dimethyl-2-
(2-iodophenyl)ethenylamine 15f (80%) as an amber oil: Rf 0.43
(40% EtOAc/hexane); 1H NMR (CDCl3) δ 2.74 (6H, s), 3.71 (3H,
s), 3.83 (3H, s), 5.44 (1H, s), 6.52 (1H, dd, J ) 7.3, 1.4 Hz),
6.59 (1H, ddd, J ) 7.5, 7.5, 1.4 Hz), 6.66 (1H, s), 6.82 (1H,
ddd, J ) 7.5, 7.3, 1.2 Hz), 7.17 (1H, s), 7.72 (1H, dd, J ) 7.3,
1.2 Hz); 13C NMR (CDCl3) δ 39.9, 55.8, 55.9, 88.3, 101.8, 107.1,
113.7, 121.3, 125.3, 127.3, 128.5, 133.5, 141.6, 148.7, 149.0,
The same procedure on R-aminonitrile 7b and bromide 17c
provided (E)-2-(2-bromo-4,5-dimethoxyphenyl)-N,N-dimethyl-
1-(2-iodophenyl)ethenylamine 15j (74%) as a yellow oil: Rf 0.40