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K. Y. Lee et al. / Tetrahedron Letters 46 (2005) 69–74
2.32 (s, 3H), 5.16 (d, J = 9.0Hz, 1H), 5.53 (d, J = 9.0Hz,
as clear oil, 102mg (55%). The spectroscopic data of
prepared compounds are as follows. For 5b and 5c we
could not obtain the exact 13C NMR spectra due to the
line broadening effect of nitrogen atom.
1H), 6.90–6.96 (m, 2H), 7.07–7.12 (m, 2H), 7.20 (d,
J = 8.1Hz, 2H), 7.29–7.35 (m, 3H), 7.50–7.53 (m, 2H),
7.80 (d, J = 8.4Hz, 2H); 13C NMR (75MHz, CDCl3) d
21.60, 49.90, 85.51 (d, J = 1.4Hz), 85.74, 115.58 (d,
J = 21.8Hz), 118.27 (d, J = 3.8Hz), 127.48, 127.72,
128.66, 128.91, 129.70, 133.69 (d, J = 8.3Hz), 137.57 (d,
J = 6.3Hz), 143.66, 161.10, 164.42. 3d: mp 122–123°C; 1H
NMR (300MHz, CDCl3) d 2.29 (s, 3H), 3.75 (s, 3H), 5.30
(d, J = 9.3Hz, 1H), 5.51 (d, J = 9.3Hz, 1H), 6.74 (d,
J = 8.7Hz, 2H), 7.03 (d, J = 8.7Hz, 2H), 7.17 (d,
J = 8.1Hz, 2H), 7.20–7.33 (m, 3H), 7.49–7.53 (m, 2H),
7.76 (d, J = 8.4Hz, 2H); 13C NMR (75MHz, CDCl3)
d21.72, 50.11, 55.57, 84.49, 86.89, 114.02, 114.39, 127.63,
127.80, 128.60, 128.92, 129.79, 133.33, 137.74, 138.03,
143.67, 160.01. 3e: mp 187–188°C;1 H NMR (300MHz,
CDCl3) d 2.31 (s, 3H), 4.96 (d, J = 9.3Hz, 1H), 5.56 (d,
J = 9.3Hz, 1H), 7.10–7.14 (m, 2H), 7.21–7.38 (m, 8H),
7.53–7.57 (m, 2H), 7.81 (d, J = 8.4Hz, 2H); 13C NMR
(75MHz, CDCl3) d 21.40, 49.77, 85.46, 86.68, 121.95,
127.32, 127.52, 128.09, 128.46, 128.57, 128.70, 129.55,
131.55, 137.37, 137.39, 143.55; Mass (70eV) m/z (rel.
intensity) 65 (60), 77 (71), 91 (100), 105 (51), 128 (46), 191
(34), 206 (M+ À SO2Tol, 90). 3f: mp 194–195°C; 1H NMR
(300MHz, CDCl3) d 2.31 (s, 3H), 2.34 (s, 3H), 4.91 (d,
J = 9.0Hz, 1H), 5.52 (d, J = 9.0Hz, 1H), 7.09–7.29 (m,
1
5a: oil; H NMR (300MHz, CDCl3) d 1.15 (t, J = 7.2Hz,
3H), 1.21 (d, J = 6.6Hz, 6H), 1.26 (t, J = 7.2Hz, 3H) 3.14
(q, J = 7.2Hz, 2H), 3.52 (septet, J = 6.6Hz, 1H), 4.13 (q,
J = 7.2Hz, 2H), 4.58 (d, J = 13.2Hz, 1H), 7.51 (d,
J = 13.2Hz, 1H); 13C NMR (75MHz, CDCl3) d 12.91,
14.80, 21.70, 41.01, 56.01, 58.84, 83.35, 149.46, 170.17. 5b:
oil; 1H NMR (300MHz, CDCl3) d 1.16 (t, J = 7.2Hz, 6H),
1.26 (t, J = 7.2Hz, 3H), 3.19 (q, J = 7.2Hz, 4H), 4.13 (q,
J = 7.2Hz, 2H), 4.57 (d, J = 12.9Hz, 1H), 7.44 (d,
J = 12.9Hz, 1H); 13C NMR (75MHz, CDCl3) d 14.66,
1
58.79, 83.37, 150.89, 170.00. 5c: oil; H NMR (300MHz,
CDCl3) d 1.26 (t, J = 7.2Hz, 3H), 2.88 (s, 6H), 4.13 (q,
J = 7.2Hz, 2H), 4.52 (d, J = 12.9Hz, 1H), 7.44 (d,
J = 12.9Hz, 1H). 5d: oil; IR (neat) 3498, 2974, 1689,
; d 1.15 (t,
1608cmÀ1 1H NMR (300MHz, CDCl3)
J = 7.2Hz, 3H), 1.21 (d, J = 6.9Hz, 6H), 3.14 (q,
J = 7.2Hz, 2H), 3.52 (septet, J = 6.9Hz, 1H), 3.66 (s,
3H), 4.58 (d, J = 13.2Hz, 1H), 7.51 (d, J = 13.2Hz, 1H);
13C NMR (75MHz, CDCl3) d 12.96, 21.71, 41.09, 50.49,
55.91, 83.00, 149.53, 170.52; Mass (70eV) m/z (rel.
intensity) 41 (100), 56 (97), 70 (72), 140 (56), 156 (49),
171 (M+, 22). 5e: oil; IR (neat) 3510, 2978, 1689,
9H), 7.42 (d, J = 8.4Hz, 2H), 7.81 (d, J = 8.4Hz, 2H); 13
C
1612cmÀ1 1H NMR (300MHz, CDCl3)
; d 1.16 (t,
NMR (75MHz, CDCl3) d 21.37, 21.68, 49.82, 85.97,
86.75, 122.32, 127.51, 127.81, 128.35, 128.79, 129.64,
129.80, 131.82, 134.76, 137.71, 138.61, 143.77. 3g: mp
224–225°C; 1H NMR (300MHz, CDCl3 + DMSO-d6) d
2.21 (s, 3H), 5.83 (s, 1H), 7.15–7.38 (m, 7H), 7.68– 7.74 (m,
3H), 7.86 (t, J = 8.4Hz, 1H), 7.98 (d, J = 8.7Hz, 1H), 8.09
(d, J = 7.8Hz, 1H), 8.59 (s, 1H), 8.91 (br s, 1H); 13C NMR
(75MHz, CDCl3 + DMSO-d6) d 19.15, 44.88, 83.35, 84.02,
119.55, 124.98, 125.11, 125.84, 125.89, 126.52, 126.65,
127.18, 127.64, 127.98, 129.52, 129.70, 136.25, 136.37,
141.12, 144.80, 146.61. 3h: oil; 1H NMR (300MHz,
CDCl3) d 3.08 (s, 3H), 4.96 (d, J = 8.1Hz, 1H), 5.64 (d,
J = 7.2Hz, 6H), 3.19 (q, J = 7.2Hz, 4H), 3.65 (s, 3H),
4.56 (d, J = 12.9Hz, 1H), 7.44 (d,J = 12.9Hz, 1H); 13C
NMR (75MHz, CDCl3) d 13.01, 43.31, 50.37, 83.03,
150.98, 170.31; Mass (70eV) m/z (rel. intensity) 41 (67), 55
(100), 98 (37), 126 (53), 142 (27), 157 (M+, 26).
13. Spectroscopic data of partial reduction product 6: 1H
NMR (300MHz, CDCl3)
d 2.35 (s, 3H), 5.07 (d,
J = 5.4Hz, 1H), 5.61 (dd, J = 9.3 and 5.4Hz, 1H), 5.87
(dd, J = 11.4 and 9.3Hz, 1H), 6.57 (d, J = 11.4Hz, 1H),
7.05–7.33 (m, 11H), 7.49 (d, J = 8.4Hz, 2H); Mass (70eV)
m/z (rel. intensity) 91 (100), 138 (30), 242 (41), 397 (M+, 2).
14. To a stirred solution of quinoline (130mg, 1mmol) in
CH3CN (2mL) was added benzoyl chloride (183mg,
1.3mmol), phenylacetylene (122mg, 1.2mmol), ZnBr2
(270mg, 1.2mmol), and N,N-diisopropylethylamine
(155mg, 1.2mmol) successively at room temperature.
After 20min the reaction mixture was poured into cold
water. After normal workup with ether, removal of
solvent, flash column chromatographic purification (hex-
anes/ether, 40:1) we obtained the desired dihydroquinoline
J = 8.1Hz, 1H), 7.30–7.49 (m, 8H), 7.60–7.64 (m, 2H); 13
C
NMR (75MHz, CDCl3) d 41.78, 49.80, 86.04, 86.98,
121.78, 127.42, 128.47, 128.73, 128.90, 129.00, 131.67,
1
137.27. 3i: mp 145–146°C; H NMR (300MHz, CDCl3) d
2.33 (s, 6H), 4.94 (d, J = 7.8Hz, 1H), 5.54 (d, J = 7.8Hz,
1H), 6.99–7.07 (m, 4H), 7.23 (d, J = 8.7Hz, 2H), 7.30–7.37
(m, 3H), 7.53–7.57 (m, 2H), 7.81 (d, J = 8.4Hz, 2H); 13C
NMR (75MHz, CDCl3) d 21.65, 21.66, 50.03, 85.01,
87.05, 119.10, 127.56, 127.75, 128.63, 128.89, 129.06,
129.76, 131.68, 137.63, 137.77, 138.97, 143.70.
8, 248mg (74%): IR (KBr) 2218, 1651cmÀ1 1H NMR
;
(300MHz, CDCl3) d 6.19–6.24 (m, 2H), 6.65–6.70 (m,
2H), 6.90 (t, J = 7.5Hz, 1H), 7.05 (td, J = 7.5 and 1.2Hz,
1H), 7.17–7.45 (m, 11H); 13C NMR (75MHz, CDCl3) d
44.42, 83.66, 85.07, 122.38, 125.10, 125.61, 125.71, 126.13,
126.53, 126.84, 127.12, 127.98, 128.06, 128.25, 128.98,
130.58, 131.79, 134.94, 135.15, 169.38; Mass (70eV) m/z
(rel. intensity) 77 (52), 105 (100), 129 (18), 230 (14), 306
(13), 335 (M+, 7).
12. Typical procedure for the synthesis of enaminone ester 5a:
To s stirred solution of ethyl propiolate (98mg, 1.0mmol)
in CH3CN (3mL) was added ZnBr2 (225mg, 1.0mmol)
and N,N-diisopropylethylamine (130mg, 1.0mmol). The
reaction mixture was stirred for 12h at 50–60°C. After the
usual aqueous workup and column chromatographic
purification process (hexanes/ether, 5:1) we obtained 5a