2
244
I. J. S. Fairlamb et al. / Tetrahedron 57 (2001) 2237±2246
1
608. dH (CDCl ) 6.05±6.09 (1H, m, C2±H), 5.79±5.84
3
7.2.3. 7-endo-Bromo-7-exo-hexylbicyclo[3.2.0]hept-2-en-
6-one (11) and 7-exo-bromo-7-endo-hexylbicyclo[3.2.0]-
hept-2-en-6-one (12). 2-Bromooctanoyl chloride (20.43 g,
84.5 mmol) was reacted with cyclopentadiene (16.75 g,
(
7
1H, m, C3±H), 4.29±4.35 (1H, dddd, J1.1, 1.5, 7.3,
.5 Hz, C5±H), 3.80±3.86 (1H, m, C1±H), 3.35±3.52
0
C4±H endo), 2.41±2.53 (1H, m, C4±H exo), 2.22±2.37
(
2H, m, C3 ±H ), 2.64±2.74 (1H, dd, J4.4, 12.4 Hz,
2
0.25 mol, 3 equiv.) and Et N (11.11 g, 0.11 mol,
3
0
d (CDCl ) 205.5 (C6, s), 136.9 (C2, d), 128.2 (C3, d), 76.5
0
0
(
1H, m, C1 ±H), 1.91±2.11 (3H, m, C2 ±H and C1 ±H).
2
1.3 equiv.) in hexane (850 mL). Puri®cation by ¯ash
chromatography using hexane-ether (9:1, v/v) initially
gave a mixture of the known endo and exo isomers
(2.28 g, 9.9%); further elution gave the pure endo isomer
as a light yellow oil (6.66 g, 29.1%). Data for endo isomer
(12): d (CDCl ) 6.01±6.05 (1H, m, C2±H), 5.75±5.79 (1H,
C
3
0
(
3
(
C7, s), 59.0 (C5, d), 54.8 (C1, d), 33.6 (C3 , t), 32.9 (C4, t),
0 0
0.7 (C1 , t) and 28.7, (C2 , t). LRMS (EI, m/z) 309
M 2 Br and Br, 10), 307 (M 2 Br and Br, 20),
1
81
81
1
79
81
1
79
79
305 (M 2 Br and Br, 10), 240 (22), 242 (44), 244
H
3
(
C H Br O: C, 39.00; H, 3.93; Br, 51.88; Found: C, 39.17;
H, 3.98. Data for exo isomer (7): IR nmax (neat) 3059, 2959,
22), 199 (45), 201 (44), 66 (C H , 100). Anal. Calcd for
m, C3±H), 4.26±4.32 (1H, ddd, J2.9, 7.7, 7.9 Hz, C5±H),
5
6
3.78±3.84 (1H, m, C1±H), 2.64±2.74 (1H, m, C4±H endo),
2.39±2.51 (1H, m, C4±H exo), 1.62±1.83 (2H, m, C1 ±H ),
1
0
12
2
0
1.30±1.52 (8H, quasi singlet, C2 ±H ´´´C5 ±H ), 0.86±0.91
2
0
0
1
5
785, 1608, 1440, 1344, 1259, 1038, 935. d (CDCl ) 5.87±
H
.90 (1H, m, C2±H), 5.70±5.74 (1H, m, C3±H), 4.03±4.09
3
2
2
0
(C2, d), 128.6 (C3, d), 78.4 (C7, s), 58.8 (C5, d), 54.9 (C1,
(3H, t, J7.0 Hz, C6 ±H ). d (CDCl ) 206.4 (C6, s), 136.5
3
C
3
(
4
1H, dd, J7.5, 7.9 Hz, C5±H), 3.59±3.62 (1H, ddd, J4.0,
0
0 0 0
d), 33.5 (C4, t), 31.7 (C1 , t), 31.5 (C2 , t), 29.0 (C3 , t), 25.1
.4, 8.0 Hz, C1±H), 3.41±3.51 (2H, m, C3 ±H ), 2.72±2.79
2
0
0
0
(
exo), 2.23±2.29 (2H, m, C1 ±H ), 2.07±2.19 (2H, m, C2 ±
1H, d, J17.2 Hz, C4±H endo), 2.40±2.50 (1H, m, C4±H
(C4 , t), 22.6 (C5 , t), 13.9 (C6 , q). Data for exo isomer
(11): d (CDCl ) 5.83±5.85 (1H, m, C2±H), 5.69±5.75 (1H,
0
H ). d (CDCl ) 205.95 (C6, s), 134.39 (C2, d), 131.15 (C3,
0
2
H
3
m, C3±H), 3.96±4.01 (1H, dd, J4.1, 8.5 Hz, C5±H),
3.55±3.58 (1H, m, C1±H), 2.72±2.79 (1H, m, C4±H
endo), 2.37±2.46 (1H, m, C4±H exo), 2.02±2.08 (2H, m,
2
C
3
0
5.53 (C4, t), 32.83 (C1 , t), 28.98 (C2 , t). Anal. Calcd for
d), 76.90 (C7, s), 57.56 (C5, d), 51.73 (C1, d), 37.00 (C3 , t),
3
0
C H Br O: C, 39.00; H, 3.93; Br, 51.88; Found: C, 39.37;
0
0
0
0
C1 ±H ), 1.30±1.62 (8H, quasi singlet, C2 ±H ´´´C5 ±H ),
2
1
0
12
2
2
2
0
(C6, s), 133.9 (C2, d), 131.6 (C3, d), 78.0 (C7,s), 57.5 (C5,
H, 3.87.
0.86±0.91 (3H, t, J6.95 Hz, C6 ±H ). d (CDCl ) 206.3
3
C
3
0 0
d), 51.6 (C1, d), 38.7 (C4, t), 33.5 (C1 , t), 31.4 (C2 , t), 28.9
7
.2.2. 7-endo-Bromo-7-exo-butylbicyclo[3.2.0]hept-2-
en-6-one (9) and 7-exo-bromo-7-endo-butylbicyclo-
0
0
0
0
(C3 , t), 25.7 (C4 , t), 22.4 (C5 , t), 13.9 (C6 , q). Anal.
Calcd for C H BrO: C, 57.58; H, 7.06; Found: C, 57.65;
H, 7.15.
4
0
3.2.0]hept-2-en-6-one (10). 2-Bromohexanoyl chloride
[
(
(
1
3
19
20.05 g, 93.9 mmol) was reacted with cyclopentadiene
18.55 g, 0.28 mol, 3 equiv.) and Et N (12.3 g, 0.12 mol,
3
1.3 equiv.) in hexane (950 mL). The usual work-up afforded
brown oil. Distillation of the crude oil gave a mixture of
exoand endo isomers (14.9 g, bp 100±1158C (1.5 mmHg)
Lit. bp 95±1008C (0.3 mmHg)). Separation of the isomers
by ¯ash chromatography using hexane-ether (19:1, v/v)
afforded the known exo isomer ®rst as a pale yellow oil
7.2.4. 7-exo-Bromo-7-endo-octylbicyclo[3.2.0]hept-2-en-
6-one (13). 2-Bromodecanoyl chloride (30.01 g,
0.112 mol) was reacted with cyclopentadiene (25.76 g,
4
0
4
0
0.39 mol, 3.5 equiv.) and Et N (14.64 g, 0.145 mol,
3
1.3 equiv.) in hexane (1300 mL). The usual work-up
afforded brown oil, which was distilled in vacuo to give
the known title compound as a pale yellow oil (12.8 g,
(
also as a pale yellow oil (7.28 g, 32%). IR n (neat) 3058,
5.97 g, 26.2%); further elution gave the known endo isomer
4
0
38.2%, bp 95±988C (0.05 mmHg) Lit. bp 133±1358C
(0.2 mmHg)). IR n (neat) 3047, 2927, 2854, 1786,
max
2
930, 1783, 1606, 1380, 1038, 936 cm . Data for endo-
1
2
isomer (10): d (CDCl ) 5.98±6.05 (1H, m, C2±H), 5.74±
max
2
1
1602 cm . d (CDCl ) 5.92±6.03 (1H, m, C2±H), 5.69±
3
H
3
H
5
8
.80 (1H, m, C3±H), 4.27±4.33 (1H, ddd, J1.5, 7.8,
5.76 (1H, m, C3±H), 4.20±4.29 (1H, dddd, J1.1, 1.6, 7.6,
8.9 Hz, C5±H), 3.72±3.80 (1H, m, C1±H), 2.62±2.73 (1H,
m, C4±H endo), 2.35±2.48 (1H, m, C4±H exo), 1.66±1.90
.5 Hz, C5±H), 3.78±3.84 (1H, m, C1±H), 2.65±2.68
(
1
1H, m, C4±H endo), 2.40±2.52 (1H, m, C4±H exo),
0
0
0 0
(2H, b, C1 ±H ), 1.29±1.60 (12H, quasi singlet, C2 ±
2
.61±1.79 (3H, m, C2 ±H and C1 ±H ), 1.29±1.48 (3H,
2
0
C4 ±H ). d (CDCl ) 206.3 (C6, s), 136.5 (C2, d), 128.6
0
0
0
m, C2 ±H and C3 ±H ), 0.92±0.95 (3H, t, J8.8 Hz,
H ´´´C7 ±H ), 0.90±0.91 (3H, t, J6.2 Hz, C8 ±H ). d
2
2
2
3
C
0
C3, d), 78.5 (C7, s), 58.9 (C5, d), 54.9 (C1, d), 33.6 (C4, t),
(CDCl ) 206.9 (C6, s), 135.9 (C2, d), 128.7 (C3, d), 83.1
3
3
C
3
0
31.9 (C2 , t), 28.9 (C3 , t), 29.6 (C4 , t), 28.2 (C5 , t), 26.15
(
(C7, s), 58.9 (C5, d), 55.0 (C1, d), 34.3 (C4, t), 32.4 (C1 , t),
0
0
EI) m/z 244 (M 2 Br, 4), 242 (M 2 Br, 4), 162
0
0
0
0
0
0
(C6 , t), 26.11 (C7 , t), 15.2 (C8 , q). d
2
7.33 (C1 , t) and (C2 , t), 22.5 (C3 , t), 13.8 (C4 , q). LRMS
1
81
1
79
0
0
0
(
COSY (CDCl3)
H±H
1
M 2 Br, 60), 79 ( Br, 80), 65 (C H , 100), 44 (98).
81
79
(
Data for exo isomer (9): dH (CDCl ) 5.84±5.89 (1H, m,
5.92 (C2±H) and 5.69 (C3±H) (s), 4.20 (C5±H) and 3.72
(C1±H) (s), 4.20 (C5±H) and 2.35 (C4±H exo) (w), 2.62
(C4±H endo) and 2.35 (C4±H exo) (s). dH±C COSY (CDCl3)
5.92 and 135.9 (C2), 5.69 and 128.7 (C3), 4.20 and 58.9
(C5), 3.72 and 55.0 (C1), 2.62/2.35 and 34.3 (C4). LRMS
5
5
3
C2±H), 5.70±5.75 (1H, m, C3±H), 3.95±4.02 (1H, dd,
J7.8, 8.0 Hz, C5±H), 3.56±3.58 (1H, m, C1±H), 2.74±
2
.80 (1H, d, J17.2 Hz, C4±H endo), 2.37±2.49 (1H, m,
0
0
1
81
1
79
C4±H exo), 2.03±2.09 (2H, m, C1 ±H ), 1.52±1.58 (2H, m,
2
(EI, m/z) 300.1 (M 2 Br, 29), 298.1 (M 2 Br, 29), 219.2
79
(M 2Br, 38), 191.2 (46), 147.1 (53), 79.1 ( Br, 86), 66.1
0
1
C2 ±H ), 1.34±1.49 (2H, m, C3 ±H ), 0.91±0.96 (3H, t,
2
2
0
d), 131.6 (C3, d), 78.1 (C7, s), 57.6 (C5, d), 51.7 (C1, s),
J7.3 Hz, C4 ±H ). d (CDCl ) 206.6 (C6, s), 134.0 (C2,
(C H , 100).
5
3
C
3
6
0
0
0
C4 , q). LRMS (EI) m/z 244 (M 2 Br, 2), 242 (M 2 Br,
3
(
8.5 (C4, t), 35.5 (C1 , t), 27.9 (C2 , t), 22.5 (C3 , t), 13.7
7.2.5. 7-exo-Bromo-7-endo-decylbicyclo[3.2.0]hept-2-en-
6-one (14). 2-Bromododecanoyl chloride (12.6 g,
42.4 mmol) was reacted with cyclopentadiene (8.39 g,
0
), 162 (M 2 Br, 45), 79 ( Br, 85), 66 (C H , 82), 65
1
81
1
79
1
81
79
2
5 6
(
C H , 100), 52 (C H , 42), 44 (98).
4
0.13 mol, 3 equiv.) and Et N (4.71 g, 46.6 mmol,
3
5
5
4