PAPER
Novel Synthetic Route to Highly Substituted 2,3-Dihydrofurans via Ammonium Ylides
2191
1H NMR (300 MHz, CDCl3): d = 7.35 (d, J = 8.4 Hz, 2 H), 7.15 (d,
J = 8.4 Hz, 2 H), 4.92 (d, J = 4.5 Hz, 1 H), 4.64 (d, J = 4.5 Hz, 1 H),
2.41 (s, 3 H), 2.05 (s, 3 H).
MS (EI, 70 eV): m/z (%) = 336 (9.34) [M+], 321 (9.59), 293 (17.50),
263 (34.69), 231 (22.87), 105 (100), 77 (70.78), 43 (65.56).
HRMS: m/z [M + H] calcd for C21H20O4: 337.1434; found:
337.1433.
13C NMR (75 MHz, CDCl3): d = 193.2, 167.1, 138.3, 134.5, 129.7,
128.6, 116.8, 116.1, 74.6, 54.4, 29.8, 14.9.
cis-3bb
Solid; mp 110–112 °C.
MS (EI, 70 eV): m/z (%) = 261(14.20) [M+], 246 (4.79), 234
(16.26), 226 (2.69), 219 (12.15), 204 (12.67), 43 (100).
IR (KBr): 2927, 1696, 1648, 1600, 1449, 1385, 1212, 1096, 1021,
756, 696 cm–1.
1H NMR (300 MHz, CDCl3): d = 6.81–7.55 (m, 10 H), 6.20 (d, J =
10.5 Hz, 1 H), 4.68 (d, J = 10.2 Hz, 1 H), 3.99 (q, J = 6.9 Hz, 2 H),
2.49 (s, 3 H), 1.03 (t, J = 7.2 Hz, 3 H).
HRMS: m/z [M + H] calcd for C14H12ClNO2: 262.0629; found:
262.0632.
cis-3ac
Solid; mp 134–136 °C.
IR (KBr): 2924, 2247, 1677, 1629, 1605, 1491, 1381, 1213, 1090
cm–1.
1H NMR (300 MHz, CDCl3): d = 7.37 (d, J = 8.4 Hz, 2 H), 7.15 (d,
J = 8.4 Hz, 2 H), 5.42 (d, J = 9.9 Hz, 1 H), 4.58 (d, J = 9.9 Hz, 1 H),
2.38 (s, 3 H), 1.99 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 194.1, 168.8, 165.1, 138.0, 135.9,
133.6, 128.7, 128.0, 127.9, 127.3, 108.0, 87.8, 59.8, 52.8, 14.4,
14.2.
MS (EI, 70 eV): m/z (%) = 336 (12.41) [M+], 321 (10.08), 293
(16.07), 263 (15.99), 231 (31.87), 105 (100), 77 (84.08), 43 (79.71).
13C NMR (75 MHz, CDCl3): d = 193.4, 167.5, 135.9, 134.9, 129.6,
HRMS: m/z [M + H] calcd for C21H20O4: 337.1434; found:
129.5, 116.1, 114.3, 73.6, 51.7, 29.7, 14.8.
337.1434.
MS (EI, 70 eV): m/z (%) = 261 (15.23) [M+], 246 (4.20), 234
(14.25), 226 (2.39), 219 (11.39), 204 (10.88), 43 (100).
trans-3bc
Sticky oil.
HRMS: m/z [M + H] calcd for C14H12ClNO2: 262.0629; found:
IR (KBr): 3067, 3017, 2924, 1697, 1672, 1623, 1598, 1490, 1446,
1381, 1223, 1093, 830, 756, 694 cm–1.
262.0625.
trans-3ba
Solid; mp 125–127 °C.
1H NMR (300 MHz, CDCl3): d = 7.18–7.86 (m, 9 H), 5.61 (d, J =
4.8 Hz, 1 H), 4.54 (d, J = 4.5 Hz, 1 H), 2.44 (s, 3 H), 1.97 (s, 3 H).
IR (KBr): 2921, 1693, 1671, 1601, 1490, 1382, 1224, 1069, 1017,
757, 696 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.24–7.89 (m, 10 H), 5.66 (d, J =
4.5 Hz, 1 H), 4.53 (d, J = 4.5 Hz, 1 H), 2.47 (s, 3 H), 1.94 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 193.72, 193.14, 168.48, 140.92,
134.24, 133.52, 129.37, 129.14, 129.05, 128.99, 116.06, 89.20,
51.37, 29.62, 15.09.
MS (EI, 70 eV): m/z (%) = 340 (0.20) [M+], 297 (68.54), 235
(13.68), 105 (42.96), 77 (37.74), 43 (100).
13C NMR (75 MHz, CDCl3): d = 194.4, 193.5, 168.6, 142.4, 134.3,
133.7, 129.3, 129.1, 127.9, 127.8, 116.0, 89.7, 52.2, 29.8, 15.2.
HRMS: m/z [M + H] calcd for C20H17ClO3: 341.0939; found:
341.0943.
MS (EI, 70 eV): m/z (%) = 306 (0.46) [M+], 263 (78.90), 201
(13.42), 105 (35.77), 77 (41.48), 43 (100).
cis-3bc
Solid; mp 125–127 °C.
HRMS: m/z [M + H] calcd for C20H18O3: 307.1329; found:
307.1332.
IR (KBr): 3015, 2924, 1698, 1671, 1623, 1597, 1489, 1446, 1384,
1214, 1088, 756, 694 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.35–7.59 (m, 5 H), 6.99 (d, J =
8.1 Hz, 2 H), 6.74 (d, J = 8.4 Hz, 2 H), 6.20 (d, J = 10.2 Hz, 1 H),
4.72 (d, J = 10.2 Hz, 1 H), 2.52 (s, 3 H), 1.97 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 193.9, 193.5, 169.2, 136.1, 135.7,
133.9, 133.6, 130.0, 128.9, 128.6, 127.9, 117.0, 87.4, 52.6, 29.7,
15.3.
cis-3ba
Sticky oil.
IR (KBr): 2924, 1697, 1667, 1601, 1494, 1446, 1386, 1217, 1071,
1021, 755, 696 cm–1.
1H NMR (300 MHz, CDCl3): d = 6.79–7.56 (m, 10 H), 6.30(d, J =
10.2 Hz, 1 H), 4.73(d, J = 10.2 Hz, 1 H), 2.52 (s, 3 H), 1.92 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 194.5, 193.8, 169.2, 137.4, 135.9,
133.7, 128.8, 128.4, 127.9, 127.7, 116.8, 87.6, 53.2, 29.8, 15.3.
MS (EI, 70 eV): m/z (%) = 340 (1.67) [M+], 297 (26.85), 235
(10.66), 105 (69.69), 77 (39.45), 43 (100).
MS (EI, 70 eV): m/z (%) = 306 (2.44) [M+], 263 (42.31), 201
(18.35), 105 (64.63), 77 (46.59), 43 (100).
HRMS: m/z [M + H] calcd for C20H17ClO3: 341.0939; found:
341.0931.
HRMS: m/z [M + H] calcd for C20H18O3: 307.1329; found:
307.1331.
trans-3ca
Solid; mp 148–150 °C.
trans-3bb
Oil.
IR (KBr): 2924, 1674, 1606, 1382, 1229, 1067, 1028, 758, 703
cm–1.
1H NMR (300 MHz, CDCl3): d = 7.12–7.74 (m, 8 H), 5.40 (d, J =
4.8 Hz, 1 H), 4.64 (d, J = 4.5 Hz, 1 H), 2.46 (s, 3 H), 1.93 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 194.6, 187.6, 168.4, 142.4, 140.5,
135.6, 134.0, 129.4, 128.6, 127.9, 127.8, 115.8, 90.5, 52.7, 29.9,
15.2.
IR (KBr): 3024, 2924, 2855, 1698, 1651, 1601, 1453, 1380, 1218,
1091, 757, 696 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.24–7.85 (m, 10 H), 5.73 (d, J =
4.5 Hz, 1 H), 4.40 (d, J = 4.5 Hz, 1 H), 3.96 (q, J = 7.2 Hz, 2 H),
2.44 (s, 3 H), 1.04 (t, J = 7.2 Hz, 3 H).
13C NMR (75 MHz, CDCl3): d = 193.7, 168.6, 165.1, 142.8, 134.1,
133.7, 129.2, 129.0, 127.8, 127.6, 107.2, 89.5, 59.7, 52.0, 14.3.
MS (EI, 70 eV): m/z (%) = 312 (0.92) [M+], 269 (100), 201 (19.94),
111 (53.90), 43 (89.76).
Synthesis 2005, No. 13, 2188–2192 © Thieme Stuttgart · New York