H. Kuroda et al. / Tetrahedron 60 (2004) 1913–1920
1919
hexane/ethyl acetate¼4/1) was obtained as a mixture of
1685, 1599, 1483, 1024, 785, 758 cm21
;
1H NMR
geometric isomers in 64% yield; IR (neat) 2957, 2860, 1616,
(400 MHz, d, ppm) 0.91 (t, J¼7.0 Hz, 3H, CH3–), 1.37
(m, 4H, –CH2–), 1.69 (m, 2H, –CH2–), 2.67 (t, J¼7.6 Hz,
2H, –CH2-furan), 6.05 (d, J¼3.20 Hz, 1H, furan-H), 6.54
(d, J¼3.2 Hz, 1H, furan-H), 7.21 (m, 1H, –Ph), 7.34 (m, 2H,
Ph), 7.62 (m, 2H, Ph); 13C NMR (100 MHz, d, ppm) 14.2
(CH3), 22.6 (CH2), 27.9 (CH2), 28.3 (CH2), 31.5 (CH2),
105.5 (CH in furan ring), 106.7 (CH in furan ring), 123.2
(Ph), 126.5 (Ph), 128.4 (Ph), 131.1 (Ph), 151.9 (O–C in
furan ring), 156.2 (O–C in furan ring). MS (EI, m/z) 214
(Mþ). Anal. Calcd for C15H18O: C 84.07, H 8.47. Found: C
84.00, H 8.60.
1
1458, 1259, 750, 698 cm21; H NMR (400 MHz, d, ppm)
0.74 (t, J¼7.1 Hz, 3H, CH3–; minor isomer), 0.84 (t,
J¼7.2 Hz, 3H, CH3–), 0.92 (t, J¼7.6 Hz, 3H, CH3–),
1.20–1.60 (m, 8H, –CH2–), 1.80 (t, J¼7.6 Hz, 2H, –CH2-
furan; minor isomer), 2.28 (s, 3H, CH3-Furan), 2.51 (t,
J¼7.6 Hz, 2H, CH2-furan), 2.61 (t, J¼7.6 Hz, 2H,
–CH2Cv), 5.80 (s, 1H, furan-H; minor isomer), 5.92 (s,
1H, furan-H), 6.46 (s, 1H, –CHv; minor isomer), 6.62 (s,
1H, –CHv), 6.46 (s, 1H, –CHv; minor isomer), 7.20–
7.50 (m, 5H, Ph),; 13C NMR (100 MHz, d, ppm) 13.6 (CH3),
13.9 (CH3), 14.0 (CH2), 22.5 (CH2), 22.7 (CH2), 25.7 (CH2),
28.7 (CH2), 31.4 (CH2), 32.5 (CH2), 109.0 (CH in furan
ring), 122.8 (Bu–C in furan), 126.0 (Ph), 126.1 (PhCHv),
127.9 (Ph), 128.4 (Ph), 133.7 (Ph), 137.6 (sCvCHPh),
148.9 (O–C in furan ring), 149.4 (O–C in furan ring). MS
(EI, m/z) 296 (Mþ). Anal. Calcd for C21H28O: C 85.08, H
9.52. Found: C 85.03, H 9.71.
4.2.22. 2-(1-Butyl-2-ethylethenyl)-5-phenylfuran. Pale
yellow oil, Rf¼0.73 on TLC; SiO2, hexane/ethyl
acetate¼4/1) was obtained as a mixture of geometric
isomers in 92% yield; IR (neat) 2959, 2932, 1606, 1523,
1485, 1458, 1024, 783, 758, 688 cm21; 1H NMR (400 MHz,
d, ppm) 0.94 (t, J¼7.2 Hz, 3H, CH3–), 0.96 (t, J¼7.2 Hz,
3H; minor isomer), 1.09 (t, J¼7.6 Hz, 3H, CH3–), 1.12 (t,
J¼7.6 Hz, 2H, CH3–; minor isomer), 1.39 (m, 2H, –CH2–
), 1.49 (m, 2H, –CH2–), 1.74 (quint, J¼7.6 Hz, 2H,
CH3CH2CHv; minor isomer), 2.24 (quint, J¼7.6 Hz, 2H,
CH3CH2CHv), 2.38 (t, J¼7.2 Hz, 2H, –CH2CH2Cv),
2.50 (t, J¼7.2 Hz, 2H, –CH2CH2Cv; minor isomer), 5.45
(t, J¼7.2 Hz, 1H, –CHv; minor isomer), 6.15 (t, J¼7.6 Hz,
1H, –CHv), 6.26 (d, J¼3.2 Hz, 1H, furan-H), 6.34 (d,
J¼3.6 Hz, 1H, furan-H; minor isomer), 6.63 (d, J¼3.2 Hz,
1H, furan-H), 6.67 (d, J¼3.6 Hz, 1H, furan-H; minor
isomer), 7.10–7.80 (m, 5H, Ph); 13C NMR (100 MHz, d,
ppm; major isomer) 14.0 (CH3), 14.3 (CH3), 21.2 (CH2),
22.8 (CH2), 27.6 (CH2), 31.8 (CH2), 106.2 (CH in furan
ring), 106.4 (CH in furan ring), 123.2 (Ph), 126.6 (vCHPh),
127.5 (Ph), 128.3 (Ph), 128.9 (Ph), 130.7 (sCvCHPh),
151.8 (O–C in furan ring), 154.9 (O–C in furan ring). MS
(EI, m/z) 254 (Mþ). Anal. Calcd for C18H22O: C 84.99, H
8.72. Found: C 84.72, H 8.79.
4.2.20. 2-(1-Butyl-2-phenylethenyl)-5-methyl-3-phenyl-
furan (2Bb). Pale yellow oil, Rf¼0.68 on TLC; SiO2,
hexane/ethyl acetate¼4/1) was obtained as a mixture of
geometric isomers in 63% yield; IR (neat) 3026, 2926, 1740,
1
1601, 1444, 1126, 956, 763 cm21; H NMR (400 MHz, d,
ppm) 0.84 (t, J¼7.2 Hz, 3H, CH3–), 1.26 (m, 2H, –CH2–),
1.51 (m, 2H, –CH2–), 2.33 (d, J¼0.8 Hz, 3H, CH3-furan),
2.39 (d, J¼0.8 Hz, 3H, CH3-furan), 2.42 (t, J¼8.0 Hz, 2H,
–CH2Cv; minor isomer), 2.58 (t, J¼8.0 Hz, 2H, CH2Cv),
6.16 (q, J¼0.8 Hz, 1H, furan-H), 6.24 (q, J¼0.8 Hz, 1H,
furan-H, minor isomer), 6.58 (s, 1H, –CHv; minor isomer),
6.77 (s, 1H, –CHv), 7.20–7.50 (m, 10H, Ph); 13C NMR
(100 MHz, d, ppm; major isomer) 13.8 (CH3), 13.9 (CH3),
22.8 (CH2), 28.6 (CH2), 31.5 (CH2), 109.6 (CH in furan
ring), 123.3 (Ph–C in furan), 126.4 (vCHPh), 126.5 (Ph),
128.0 (Ph), 128.1 (Ph), 128.4 (Ph), 128.5 (Ph), 133.1 (Ph),
135.0 (Ph), 137.4 (sCvCHPh), 149.1 (O–C in furan ring),
150.2 (O–C in furan ring). MS (EI, m/z) 316 (Mþ). Anal.
Calcd for C23H24O: C 87.30, H 7.64. Found: C 86.86, H
7.87.
4.2.23. 2-(1-Butyl-4-phenyl-1,3-butadienyl)-5-phenyl-
furan. Pale yellow oil, Rf¼0.73 on TLC; SiO2, hexane/ethyl
acetate¼4/1) was obtained as a mixture of geometric
isomers in 90% yield; IR (neat) 3032, 2957, 2932, 1606,
4.2.21. 2-(1-Butyl-2-phenylethenyl)-4,5-diphenylfuran
(2Cb). Pale yellow oil, Rf¼0.60 on TLC; SiO2, hexane/
ethyl acetate¼4/1) was obtained as a mixture of geometric
isomers in 70% yield; IR (neat) 2959, 2870, 1703, 1599,
1532, 1506, 1250, 1176, 1035, 758, 690 cm21; H NMR
1
(400 MHz, d, ppm) 0.94 (t, J¼7.2 Hz, 3H, CH3–; minor
isomer), 0.97 (t, J¼7.6 Hz, 3H, CH3–), 1.44 (m, 2H,
–CH2–), 1.61 (m, 2H, –CH2–), 2.46 (t, J¼7.6 Hz, 2H,
–CH2CH2Cv; minor isomer), 2.60 (t, J¼7.2 Hz, 2H,
–CH2CH2Cv), 6.21 (d, J¼11.6 Hz, 1H, PhCHvCHCHv;
minor isomer), 6.44 (d, J¼3.6 Hz, 1H, furan-H), 6.49 (d,
J¼3.6 Hz, 1H, furan-H; minor isomer), 6.64 (d, J¼15.6 Hz,
1H, PhCHvCH–; minor isomer), 6.68 (d, J¼3.20 Hz, 1H,
furan-H), 6.72 (d, J¼3.6 Hz, 1H, furan-H; minor isomer),
6.73 (d, J¼15.2 Hz, 1H, PhCHvCH–), 6.95 (d, J¼11.6 Hz,
1H, PhCHvCHCHv), 7.16 (dd, J¼11.6, 15.6 Hz, 1H,
PhCHvCH–), 7.20–7.80 (m, 10H, Ph) 7.96 (dd, J¼11.6,
15.6 Hz, 1H, PhCHvCH–; minor isomer); 13C NMR
(100 MHz, d, ppm; major isomer) 13.9 (CH3). 22.8 (CH2),
28.0 (CH2), 32.3 (CH2), 107.0 (CH in furan ring), 108.5 (CH
in furan ring), 123.4 (Ph), 123.8 (PhCHvCH–CHv),
124.6 (PhCHvCH–), 126.0 (Ph), 127.0 (Ph), 127.0 (Ph),
128.3 (Ph), 130.4 (vCH–CHvC,), 130.7 (Ph), 132.6
(PhCHvCH–), 137.5 (Ph), 152.8 (O–C in furan ring),
154.7 (O–C in furan ring). MS (EI, m/z) 328 (Mþ). Anal.
1
1446, 1147, 763, 696 cm21; H NMR (400 MHz, d, ppm)
0.88 (t, J¼7.6 Hz, 3H, CH3–), 1.38 (m, 2H, –CH2–), 1.63
(m, 2H, –CH2–), 2.47 (t, J¼7.6 Hz, 2H, –CH2Cv; minor
isomer), 2.56 (t, J¼8.2 Hz, 2H, –CH2Cv), 6.24 (s, 1H,
furan-H; minor isomer), 6.47 (s, 1H, furan-H), 7.14 (s, 1H,
–CHv), 7.10–7.55 (m, 15H, Ph); 13C NMR (100 MHz, d,
ppm) 14.0 (CH3), 23.2 (CH2), 28.4 (CH2), 32.1 (CH2), 110.7
(CH in furan ring), 124.2 (Ph–C in furan), 124.5 (vCHPh),
126.0 (Ph), 126.5 (Ph), 127.1 (Ph), 127.3 (Ph), 128.2 (Ph),
128.3 (Ph), 128.5 (Ph), 128.6 (Ph), 128.7 (Ph), 130.9 (Ph),
131.2 (Ph), 134.2 (Ph), 137.3 (sCvCHPh), 147.3 (O–C in
furan ring), 154.1 (O–C in furan ring). MS (EI, m/z) 378
(Mþ). Anal. Calcd for C28H26O: C 88.85, H 6.92. Found: C
88.64, H 7.14.
4.2.21. 2-Pentyl-5-phenylfuran (20Aa). Colorless oil,
Rf¼0.63 on TLC; SiO2, hexane/ethyl acetate¼4/1) was
obtained in 58% yield; IR (neat) 2957, 2930, 2870, 1738,