N. Cos¸kun, I. Erden / Tetrahedron 67 (2011) 8607e8614
8613
3.6, 1.6 Hz, 1H), 6.52e6.45 (m, 1H), 6.37 (dt, J¼5.0, 1.8 Hz, 1H), 6.37
2.3 Hz, 2H), 2.25 (s, 6H). 13C NMR (126 MHz, CDCl3):
131.4, 121.3, 23.8.
d
150.8, 143.3,
(dt, J¼5.0, 1.8 Hz, 1H), 3.07 (s, 6H). 13C NMR (126 MHz, CDCl3):
d
151.8, 141.5, 140.7, 134.4, 133.6, 128.9, 128.3, 125.4, 120.2, 112.7,
40.8.
4.4.12. 1-(1-(Cyclopenta-2,4-dien-1-ylidene)ethyl)-4-methylbenzene
(3l). Prepared according to method B by using 3 equiv of pyrroli-
4.4.4. 4-(Cyclopenta-2,4-dienylidenemethyl)phenol (3d). (Method
dine. Reddish oil. 1H NMR (300 MHz, CDCl3):
d
7.31 (2H, d, J¼8 Hz),
A). Solid, does not melt below 260 ꢁC 1H NMR (300 MHz, CDCl3):
7.21 (2H, d, J¼8 Hz), 6.67e6.62 (1H, m), 6.57 (1H, d, J¼5 Hz), 6.49
d
7.54 (d, J¼8.6 Hz, 2H), 7.16 (s, 1H), 6.88 (d, J¼8.6 Hz, 2H), 6.72 (d,
(1H, d, J¼5 Hz), 6.24e6.20 (1H, m), 2.54 (3H, s), 2.40 (3H, s).13C NMR
J¼5.2 Hz,1H), 6.67 (dd, J¼5.2,1.6 Hz,1H), 6.50 (d, J¼4.9 Hz,1H), 6.33
(75 MHz, CDCl3): d 150.0, 143.0, 139.0, 138.2, 131.5, 131.2, 129.2,
(dd, J¼3.3, 1.7 Hz, 1H). 13C NMR (75 MHz, CDCl3):
d
156.6, 143.2,
128.5, 123.7, 121.0, 22.5, 21.2.
138.1, 134.9, 132.6, 129.8, 129.6, 127.3, 119.8, 115.7. ESI-HRMS cal-
culated for C12H11Oþ (MþHþ) 171.0804, found 171.0895.
4.4.13. 5-(2-Methylpropylidene)cyclopenta-1,3-diene (3n). (Method
C). Yellow oil. 1H NMR (300 MHz, CDCl3):
d
6.54 (t, J¼3.6 Hz, 2H),
4.4.5. 1-(Cyclopenta-2,4-dienylidenemethyl)-3-methoxybenzene
6.48 (d, J¼5.0 Hz, 1H), 6.26 (d, J¼10.1 Hz, 1H), 6.23e6.19 (m, 1H),
(3e). (Method C). 1H NMR (300 MHz, CDCl3):
d
7.34 (t, J¼7.9 Hz,1H),
3.11e2.94 (m, 1H), 1.15 (d, J¼6.6 Hz, 6H). 13C NMR (75 MHz, CDCl3)
7.19 (d, J¼8.7 Hz, 2H), 7.13 (s, 1H), 6.93 (dd, J¼8.2, 2.1 Hz, 1H), 6.69
d 149.7, 143.4, 132.8, 130.6, 125.8, 119.1, 30.3, 23.0.
(dt, J¼5.3, 3.5 Hz, 2H), 6.53 (d, J¼5.0 Hz, 1H), 6.34 (dd, J¼3.4, 1.7 Hz,
1H), 3.86 (s, 3H). 13C NMR (75 MHz, CDCl3):
d
159.6, 145.3, 138.0,
4.4.14. 5-Ethylidenecyclopenta-1,3-diene (3o). (Method C). Yellow
135.4, 130.9, 129.6, 127.1, 123.2, 120.3, 115.56, 114.9, 55.2.
oil. 1H NMR (300 MHz, CDCl3):
d
6.61 (t, J¼1.6 Hz, 2H), 6.58e6.48
(m, 2H), 6.26 (dt, J¼5.1, 1.7 Hz, 1H), 2.21 (d, J¼7.3 Hz, 3H). 13C
4.4.6. 4-(Cyclopenta-2,4-dienylidenemethyl)-1,2-dimethoxybenzene
NMR (75 MHz, CDCl3):
16.7.
d 146.9, 137.8, 132.9, 130.6, 125.4, 118.8,
(3f). (Method C). Orange crystals, mp 72e73 ꢁC. Lit.32 mp 72 ꢁC 1H
NMR (500 MHz, CDCl3):
d 7.23e7.19 (m, 2H), 7.18 (s, 1H), 6.93 (d,
J¼8.2 Hz, 1H), 6.75 (d, J¼5.3 Hz, 1H), 6.70 (ddd, J¼5.2, 3.5, 1.6 Hz,
4.4.15. 5-Propylidenecyclopenta-1,3-diene (3p). (Method C). Yellow
oil. Yield 85%. 1H NMR (300 MHz, CDCl3):
1H), 6.51 (dd, J¼3.7, 1.4 Hz, 1H), 6.35 (dt, J¼5.1, 1.8 Hz, 1H), 3.95 (s,
d
6.55 (dd, J¼4.7, 3.5 Hz,
3H), 3.95 (s, 3H). 13C NMR (126 MHz, CDCl3):
d
151.1, 149.8, 144.2,
2H), 6.45 (dd, J¼18.2, 6.5 Hz, 2H), 6.23 (dd, J¼3.5, 1.6 Hz, 1H), 2.57
139.2, 135.8, 130.6, 130.5, 128.2, 125.5, 120.5, 113.9, 111.9, 56.7, 56.6.
(p, J¼7.6 Hz, 2H), 1.17 (t, J¼7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3):
d
145.2, 144.6, 132.9, 130.7, 125.6, 118.9, 24.3, 14.0.
4.4.7. 1-(Cyclopenta-2,4-dienylidenemethyl)benzene (3g). (Method
C). 1H NMR (300 MHz, CDCl3):
d
7.61 (d, J¼6.9 Hz, 2H), 7.51e7.32 (m,
4.4.16. 5-Cyclobutylidenecyclopenta-1,3-diene (3q). (Method C).
Yellow oil. 1H NMR (300 MHz, CDCl3):
6.45 (d, J¼5.2 Hz, 2H),
3H), 7.24 (s, 1H), 6.76e6.64 (m, 2H), 6.54 (d, J¼5.1 Hz, 1H), 6.35 (dd,
d
J¼3.4, 1.7 Hz, 1H). 13C NMR (75 MHz, CDCl3):
d
145.2, 138.1, 136.7,
6.31 (dd, J¼4.4, 2.0 Hz, 2H), 3.14 (t, J¼7.8 Hz, 4H), 2.18 (p,
135.4, 130.8, 130.6, 128.9, 128.6, 127.1, 120.3.
J¼7.9 Hz, 2H). 13C NMR (75 MHz, CDCl3):
d 160.3, 138.7, 130.2,
119.8, 32.2, 16.9.
4.4.8. 1-Chloro-4-(cyclopenta-2,4-dienylidenemethyl)benzene
(3h). (Method C). Red crystals, mp 43e45 ꢁC. 1H NMR (300 MHz,
4.4.17. 5-Cyclopentylidenecyclopenta-1,3-diene (3r). (Method C).
CDCl3):
d
7.52 (d, J¼8.5 Hz, 2H), 7.40 (d, J¼8.5 Hz, 2H), 7.16 (s, 1H),
Yellow oil. 1H NMR (300 MHz, CDCl3):
d
6.44 (dt, J¼6.2, 2.9 Hz, 4H),
6.68 (dt, J¼13.4, 3.3 Hz, 2H), 6.54 (d, J¼4.8 Hz, 1H), 6.33 (dd, J¼3.6,
2.84 (t, J¼7.2 Hz, 4H), 1.91e1.73 (m, 4H). 13C NMR (75 MHz, CDCl3):
1.6 Hz, 1H). 13C NMR (75 MHz, CDCl3):
135.1, 131.7, 131.1, 128.9, 127.1, 119.9.
d
145.6, 136.4, 135.8, 135.1,
d 162.5, 138.3, 130.0, 121.3, 33.0, 26.0.
4.4.18. 1-(Cyclopenta-2,4-dien-1-ylidene)-2-methylcyclohexane
4.4.9. 1-(Cyclopenta-2,4-dien-1-ylidenemethyl)-4-nitrobenzene
(3i). To a solution of 4-nitrobenzaldehyde (5 mmol) and cyclo-
pentadiene (6.0 mmol, 0.3966 g, 0.492 mL) in reagent grade
(3s). (Method C). Yellow oil. 1H NMR (300 MHz, CDCl3):
d
6.70e6.45 (m, 4H), 3.48e3.32 (m,1H), 2.94 (d, J¼14.0 Hz,1H), 2.49
(td, J¼13.7, 4.9 Hz, 1H), 2.06e1.93 (m, 1H), 1.86e1.43 (m, 5H), 1.29
(d, J¼7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3):
d 162.4, 139.2, 130.6,
ꢀ
acetonitrile (5 mL) molecular sieve (1.5 g, 3 A) was added, fol-
lowed by dropwise addition of pyrrolidine (0.0532 g, 15 mol %).
The mixture was stirred overnight and filtered through sintered
glass funnel and the solvent evaporated under vacuum. The
mixture was separated by flash chromatography using silica
packed column and hexane/ethyl acetate as eluent. For further
purification preparative TLC was used. Reddish oil. 1H NMR
120.1, 119.5, 35.1, 33.7, 28.9, 28.4, 20.5, 19.5.
4.4.19. 4-(Cyclopenta-2,4-dien-1-ylidene)pentanoic acid (3t). (Method
A without MS). Yellow solid mp 65e67 ꢁC. Lit.12 mp 66e67 ꢁC. 1H
NMR (300 MHz, CDCl3):
d
10.9 (br s, 1H), 6.52 (d, J¼5.7 Hz, 4H),
2.95e2.82 (m, 2H), 2.62 (dd, J¼8.8, 7.0 Hz, 2H), 2.22 (s, 3H). 13C NMR
(500 MHz, CDCl3):
d
8.27 (1H, d, J¼9 Hz), 7.70 (1H, d, J¼9 Hz),
(75 MHz, CDCl3):
31.4, 20.5.
d 178.9, 149.6, 143.4, 131.5, 131.3, 120.7, 120.1, 33.4,
7.20 (1H, s), 6.81e6.63 (1H, m), 6.57 (1H, dd, J¼5, 2 Hz),
6.38e6.26 (1H, m). 13C NMR (126 MHz, CDCl3):
d 148.6, 147.8,
143.3, 137.5, 134.6, 132.9, 131.2, 127.2, 124.1, 120.1.
4.4.20. 5-(Cyclopenta-2,4-dien-1-ylidene)hexanoic acid (3u). (Method
A without MS). Yellow oil, which solidifies on standing in the fridge.
4.4.10. 1-(Cyclopenta-2,4-dien-1-ylidenemethyl)-3-nitrobenzene
1H NMR (300 MHz, CDCl3):
d
10.01 (br s, 1H), 6.58e6.41 (m, 4H), 2.60
(3j). Prepared and purified as 3i. Reddish oil. 1H NMR (300 MHz,
(t, J¼7.7 Hz, 2H), 2.41 (t, J¼7.4 Hz, 2H), 2.22 (s, 3H), 1.93 (p, J¼7.5 Hz,
CDCl3):
d
8.42 (1H, s), 8.21 (1H, dd, J¼8, 1 Hz), 7.86 (1H, d, J¼8 Hz),
2H). 13C NMR (75 MHz, CDCl3):
d 179.5,151.6, 143.2, 131.1, 131.0,120.6,
7.60 (1H, t, J¼8 Hz), 7.20 (1H, s), 6.76e6.67 (1H, m), 6.61 (1H, d,
120.2, 35.7, 33.35, 23.6, 20.6. ESI-HRMS calculated for C11H15O2þ
J¼5 Hz), 6.56 (1H, d, J¼5 Hz), 6.36e6.28 (1H, m). 13C NMR (75 MHz,
(MþHþ) 179.1067, found 179.1086.
CDCl3):
d 148.3, 147.4, 138.2, 136.9, 135.9, 134.2, 132.2, 129.5, 126.9,
124.8, 123.2, 119.6.
4.4.21. 2-(Cyclopenta-2,4-dienylidene)propan-1-ol (3v). (Method C).
Yellow oil, which slowly solidifies in the fridge. Mp 52e53 ꢁC.
4.4.11. 5-(Propan-2-ylidene)cyclopenta-1,3-diene (3k). (Method C).
Lit.33 mp 54e54.5 ꢁC 1H NMR (300 MHz, CDCl3):
d
6.52 (dd, J¼6.2,
1H NMR (500 MHz, CDCl3):
d
6.58e6.56 (m, 2H), 6.52 (dd, J¼4.0,
4.0 Hz, 4H), 4.54 (s, 2H), 2.28 (s, 3H), 1.91 (br s, 1H). 13C NMR