7
0.0, 107.2, 113.0, 128.5, 132.00, 145.4, 152.1 and 165.0; m/z
br t, J 4.0), 5.77 (1 H, dddd, J 10.0, 4.5, 2.5 and 1.2) and 5.95
(
(
EI, 70 eV) (rel. int.) 181 (250 Ϫ CH CHCHCHO, 3%), 109
43), 67 (47), 55 (100) and 53 (12) (Found: C, 72.03; H, 8.77.
(1 H, ddm, J 10.0 and 5.0); δ (75.5 MHz) 20.6, 21.4, 23.6, 26.0,
2
C
26.3, 26.9, 48.5, 62.6, 79.8, 89.0, 126.4, 131.4 and 178.4; m/z (EI,
70 eV) (rel. int.) 138 (24 Ϫ CO CCH CH , 2%), 80 (100), 79
Calc. for C H O : C, 71.97; H, 8.86%).
15
22
3
2
3
3
(
E)-1,3-Dimethyl-4-oxaocta-5,7-dienyl acrylate 15. Purific-
(44), 77 (13) and 55 (19) (Found: C, 69.65; H, 8.91%).
3,3,4,4-Tetramethyl-2,5-dioxa-1â,7á-bicyclo[5.4.0]undec-10-
ation: eluent light petroleum–Et O (90:10), as a mixture of
2
two diastereoisomers in a 60:40 ratio (55% yield); for syn-15
en-6-one 19. Purification: eluent light petroleum–Et O (90:10);
2
Ϫ1
Ϫ1
νmax(film)/cm 1735 and 1640; δ (300 MHz) 1.19 (3 H, d, J
νmax(film)/cm 1735; δ (300 MHz) 1.24 (6 H, s), 1.40 (3 H, s),
H
H
6
.0), 1.22 (3 H, d, J 6.0), 1.72 (2 H, dd, J 6.0 and 6.5), 3.90 (1 H,
1.41 (3 H, s), 1.73–1.76 (2 H, m), 2.15–2.20 (2 H, m), 2.79 (1 H,
ddd, J 13.0, 10.0 and 3.0), 4.32 (1 H, ddd, J 10.0, 4.5 and 2.0),
5.50 (1 H, ddt, J 10.0, 4.5 and 2.0) and 5.89 (1 H, dm, J 10.0); δC-
(75.5 MHz) 19.3, 22.2, 23.7, 24.1, 27.3, 27.8, 46.8, 67.5, 79.0,
87.5, 128.7, 129.9 and 174.9; m/z (EI, 70 eV) (rel. int.): 138
(224 Ϫ CO CCH CH , 2%), 80 (100), 79 (48), 77 (12) and 59
ept, J 6.0), 4.72 (1 H, dd, J 10.0 and 2.0), 4.88 (1 H, dd, J 17.0
and 2.0), 5.01 (1 H, m), 5.55 (1 H, dd, J 13.0 and 10.5), 5.76
(
(
(
1 H, dd, J 11.0 and 1.5), 6.05 (1 H, dd, J 17.0 and 11.0), 6.15
1 H, dt, J 17.0 and 10.0), 6.32 (1 H, dd, J 17.0 and 1.5) and 6.35
1 H, dd, J 13.0 and 1.5); δ (75.5 MHz) 19.9, 20.1, 42.2, 68.2,
C
2
3
3
7
7
3.9, 108.9, 111.2, 128.7, 130.3, 133.5, 149.6 and 165.4; m/z (EI,
(12).
2,11-Dioxa-1á,4á,9á,13á-tricyclo[11.4.0.0 ]heptadec-16-en-
4
,9
0 eV) (rel. int.) 141 (210 Ϫ CH CHCHCHO, 12%), 70 (13), 69
2
4
,9
(
50), 55 (100) and 53 (7).
12-one 20b and 2,11-dioxa-1â,4á,9á,13â-tricyclo[11.4.0.0 ]-
heptadec-16-en-12-one 20a (see footnote***). Purification:
eluent light petroleum–Et O (95:5); δ (CD C D ; 80 ЊC; 300
Ϫ1
For anti-15 νmax(film)/cm 1735 and 1640; δ (300 MHz) 1.19
H
(
3 H, d, J 6.0), 1.22 (3 H, d, J 6.0), 1.58 (1 H, ddd, J 15.0, 6.0
2
H
3
6
5
and 5.0), 2.00 (1 H, ddd, J 15.0, 8.0 and 6.0), 3.90 (1 H, hex,
J 6.0), 4.72 (1 H, dd, J 10.0 and 2.0), 4.88 (1 H, dd, J 17.0 and
MHz) 1.00–2.00 (14 H, m), 2.52 (1 H, m), 3.28 (1 H, dd, J 11.0
and 1.5), 3.75 (1 H, br dd, J 11.0 and 5.0), 3.84 (1 H, m), 3.98 (1
H, dd, J 11.0 and 5.0), 5.05 (1 H, br t, J 11.0) and 5.70 (2 H, m);
δ (CD C D ; 80 ЊC; 75.5 MHz) 21.6, 24.5, 25.5, 26.6, 28.1, 29.1,
2
.0), 5.01 (1 H, m), 5.55 (1 H, dd, J 13.0 and 10.5), 5.76 (1 H,
dd, J 11.0 and 1.5), 6.05 (1 H, dd, J 17.0 and 11.0), 6.15 (1 H, dt,
J 17.0 and 10.0), 6.32 (1 H, dd, J 16.0 and 2.0) and 6.35 (1 H,
C
3
6
5
35.0, 41.1, 46.1, 68.0, 77.4, 79.3, 128.4, 131.0 and 174.7; m/z (EI,
ϩ
dd, J 13.0 and 1.5); δ (75.5 MHz) 20.1, 20.4, 43.0, 68.1, 73.9,
70 eV) (rel. int.) 181 (M Ϫ CHCHOCH CH, 11%), 109 (100),
C
2
1
07.9, 111.2, 128.9, 130.2, 133.2, 149.2 and 165.4; m/z (EI, 70
95 (50), 80 (51) and 55 (81).
eV) (rel. int.) 141 (210 Ϫ CH CHCHCHO, 12%), 70 (13), 69
For isomer 20 δ (CD C D ; 80 ЊC; 300 MHz) 1.00–2.00
2
H
3
6
5
(
53), 55 (100) and 53 (6) (Found: C, 68.66; H, 8.57. Calc. for
(14 H, m), 3.35 (1 H, dd, J 11.0 and 10.0), 3.79 (1 H, dd, J 11.0
and 5.0), 3.89 (1 H, m), 3.90 (1 H, br t, J 11.0), 4.65 (1 H, dd,
J 11.0 and 4.0) and 5.70 (2 H, m); δ (CD C D ; 80 ЊC; 75.5
C H O : C, 68.55; H, 8.63%).
12
18
3
C
3
6
5
Representative procedure for intramolecular Diels–Alder
cycloaddition (products 16–24)
MHz) 21.8, 23.0, 25.4, 25.8, 27.3, 30.5, 40.7, 44.7, 46.9, 66.3,
76.8, 79.1, 128.0, 131.4 and 174.2; m/z (EI, 70 eV) (rel. int.) 250
3
ϩ
A solution of triene (2.0 mmol) in toluene (5.0 cm ) or benzo-
M , 2%), 109 (100), 79 (33), 55 (100) and 41 (34).
3
nitrile (5.0 cm ) was degassed with argon. The solution was
For isomer 20 δ (CD CN; 300 MHz) 1.50 (2 H, m), 1.80
H
3
refluxed in the presence of hydroquinone under inert atmos-
phere, and the reaction was followed by TLC (eluent light
(1 H, m), 2.10 (2 H, m), 2.30 (1 H, m), 2.79 (1 H, ddd, J 10.0, 6.0
and 3.5), 3.50 (1 H, dd, J 12.0 and 10.0), 3.95 (1 H, dd, J 10.0
and 5.0), 4.02 (1 H, m), 4.17 (1 H, t, J 10.5), 4.55 (1 H, dd, J 10.5
and 3.5), 5.80 (1 H, m) and 5.95 (1 H, m).
petroleum–Et O). After the time indicated in Table 1 the mix-
2
ture was washed with 10% aq. NaOH, the organic solvent was
4
,9
removed in vacuo and, after column chromatography [Et O–
2,11-Dioxa-1â,4á,9á,13á-tricyclo[11.4.0.0 ]heptadec-16-en-
2
light petroleum (10:90)], the cycloadduct was isolated.
12-one 21a and 21b (see footnote***). Purification: eluent light
Ϫ1
1
0-Methyl-2,6-dioxa-1á,8á-bicyclo[6.4.0]dodec-11-en-7-one
petroleum–Et O (95:5); νmax(film)/cm
1740; δ (CD CN;
2
H 3
1
6. Needles, mp 105–107 ЊC (from light petroleum–Et O);
300 MHz) 1.25–1.70 (8 H, m), 1.80 (2 H, m), 1.90 (1 H, m), 2.10
(2 H, m), 2.20 (1 H, m), 2.42 (1 H, ddd, J 13.0, 10.0 and 2.5),
3.25 (1 H, t, J 11.0), 3.94 (1 H, dd, J 11.0 and 5.0), 4.05 (1 H, m),
4.30 (1 H, m), 4.40 (1 H, m), 5.55 (1 H, m) and 5.65 (1 H, m);
δ (CD C D ; 75.5 MHz) 24.7, 25.1, 26.5, 27.5, 30.6, 37.6, 40.7,
2
Ϫ1
νmax(CHCl )/cm 1730; δ (300 MHz) 1.05 (3 H, d, J 7.0), 1.40
3
H
(
1 H, dt, J 13.0 and 11.0), 1.62 (1 H, m), 1.95 (1 H, dt, J 12.5
and 4.5), 2.08 (1 H, m), 2.29 (1 H, m), 2.75 (1 H, ddd, J 13.0, 5.0
and 3.0), 3.56 (1 H, dd, J 12.0 and 10.0), 3.88 (1 H, ddd, J 12.0,
C
3
6
5
1
1.0 and 6.0), 4.20 (1 H, ddm, J 18.0 and 4.0), 4.22 (1 H, br d,
50.6, 63.7, 68.4, 77.8, 78.5, 127.9, 132.7 and 177.1; m/z (EI, 70
ϩ
J 3.0), 4.80 (1 H, dd, J 11.0 and 7.5) and 5.75 (2 H, s); δ (75.5
eV) (rel. int.) 181 (M Ϫ CHCHOCH CH,11%), 109 (100), 80
C
2
MHz) 21.0, 27.5, 30.0, 30.1, 45.3, 63.9, 72.4, 79.2, 125.4, 137.9
and 176.2; m/z (EI, 70 eV) (rel. int.) 196 (M , 3%), 113 (100), 79
(51), 79 (50) and 55 (84) (Found: C, 71.86; H, 8.93. Calc. for
C H O : C, 71.97; H, 8.86%).
ϩ
15
22
3
(
21), 77 (20) and 55 (100) (Found: C, 67.28; H, 8.19. Calc. for
3á,5á-Dimethyl-2,6-dioxa-1â,8á-bicyclo[6.4.0]dodec-11-en-
C H O : C, 67.32; H, 8.22%).
7-one 22. Purification: eluent light petroleum–Et O (95:5);
11
16
3
2
Ϫ1
4
,4,10-Trimethyl-2,6-dioxa-1â,8á-bicyclo[6.4.0]dodec-11-en-
νmax(film)/cm 1735; δ (300 MHz) 1.15 (3 H, d, J 7.0), 1.30
H
7
-one 17. Purification: eluent light petroleum–Et O (70:30);
(3 H, d, J 7.0), 1.60–1.90 (2 H, m), 1.75–1.90 (2 H, m), 2.10
(2 H, m), 2.60 (1 H, ddd, J 12.0, 9.0 and 3.0), 3.55 (1 H, dq,
J 10.0 and 6.5), 3.55 (1 H, dq, J 10.0 and 6.5), 4.09 (1 H, dm,
J 9.5), 5.28 (1 H, ddq, J 12.0, 6.5 and 3.0) and 5.60 (2 H, br s);
2
Ϫ1
νmax(film)/cm 1731; δ (300 MHz) 0.92 (3 H, s), 0.94 (3 H, s),
1
H
.10 (3 H, d, J 7.0), 1.60 (1 H, ddt, J 14.0, 2.5 and 1.5), 2.10
(
1 H, ddd, J 14.0, 13.0 and 6.0), 2.40 (1 H, m), 2.92 (1 H, ddd,
J 13.0, 9.0 and 2.5), 3.06 (1 H, d, J 12.5), 3.58 (1 H, dd, J 12.5
and 1.0), 3.71 (1 H, dd, J 12.0 and 1.0), 3.95 (1 H, dq, J 9.0 and
δ (75.5 MHz) 20.7, 21.5, 24.0, 24.1, 47.7, 48.8, 75.5, 79.7, 86.4,
127.9, 131.0 and 180.4; m/z (EI, 70 eV) (rel. int.) 141 (M Ϫ
C
ϩ
1
.5), 4.5 (1 H, d, J 12.0), 5.55 (1 H, dt, J 10.0 and 2.0) and 5.75
CH CHCHCHO, 40%), 79 (80), 69 (100), 55 (100) and 41 (61)
2
(
1 H, dddd, J 10.0, 4.0, 2.0 and 1.5); δ (75.5 MHz) 20.1, 20.8,
(Found: C, 68.61; H, 8.60. Calc. for C H O : C, 68.55; H,
C
12 18
3
2
1
6
1.8, 28.2, 30.6, 37.9, 39.0, 72.7, 75.9, 81.2, 127.6, 134.5 and
76.8; m/z (EI, 70 eV) (rel. int.) 224 (M , 2%), 141 (48), 79 (47),
9 (48) and 55 (100) (Found: C, 69.57; H, 8.89. Calc. for
8.63%).
ϩ
3â,5á-Dimethyl-2,6-dioxa-1á,8á-bicyclo[6.4.0]dodec-11-en-7-
one 23. Purification: eluent light petroleum–Et O (95:5);
νmax(film)/cm 1748; δ (300 MHz) 1.25 (3 H, d, J 7.0), 1.31
2
Ϫ1
C H O : C, 69.61; H, 8.99%).
13
20
3
H
3
,3,4,4-Tetramethyl-2,5-dioxa-1á,7á-bicyclo[5.4.0]undec-10-
(3 H, d, J 7.0), 1.60–1.75 (4 H, m), 2.05–2.30 (2 H, m), 2.74
(1 H, ddd, J 13.0, 5.5 and 3.0), 3.85 (1 H, dq, J 9.0 and 6.5), 4.30
(1 H, m), 5.11 (1 H, pent, J 6.5), 5.75 (1 H, m) and 5.95 (1 H,
en-6-one 18. Needles, mp 118–121 ЊC (from eluent light
petroleum–Et O); ν (CHCl )/cm 1735; δ (300 MHz) 1.24
Ϫ1
2
max
3
H
(
3 H, s), 1.34 (3 H, s), 1.47 (3 H, s), 1.48 (3 H, s), 2.06–2.08 (2 H,
m); δ (75.5 MHz) 20.7, 21.5, 24.0, 24.1, 47.8, 48.7, 75.5, 79.7,
86.4, 127.9, 131.0 and 180.4; m/z (EI, 70 eV) (rel. int.) 210 (M ,
C
ϩ
m), 2.22–2.30 (2 H, m), 2.79 (1 H, dt, J 12.0 and 4.5), 4.45 (1 H,
J. Chem. Soc., Perkin Trans. 1, 1998
887