T. Tsuno et al. / Tetrahedron 58 (2002) 7681–7689
7687
5-Me£2), 32.8 (q, 1-C), 37.0 (s, 5-C), 78.0 (t, 8-C), 98.2 (d,
6-C), 143.2 (s, 3-C), 151.2 (d, 4-C), 198.0 (s, CvO), 205.3
(s, CvO), 207.2 (s, 7-C); MS m/z (rel. intensity) 192 (Mþ,
4), 178 (10), 177 (69), 159 (10), 150 (12), 149 (31), 137
(11), 135 (21), 134 (15), 107 (11), 91 (16), 43 (100).
HRMS Found: m/z 192.1095. Calcd for C12H16O2; Mþ,
192.1151.
solvent, the residual oil was subjected to medium-pressure
silica gel chromatography using 2.5% ether–hexane as an
eluent to give (Z )-2-(2,2,5-trimethyl-3,4-hexadienylidene)-
cyclopentanone (9: 50 mg, 6%), 2-isopropylidene-10,10-
dimethyl-3-oxatricyclo[7.1.0.04,8]deca-4(8)-ene (10: 42 mg,
5%), cis-3-isopropylidene-5,5-dimethylspiro[bicyclo[2.1.0]-
pentane-2,20-cyclopentanone (11: 91 mg, 11%), and its
trans-isomer (12: 140 mg, 17%).
Data for 6. Yield 21%; IR (neat) 1967 (CvCvC), 1712
(CvO), 1665 (CvO), 1626 (CvC) cm21
;
1H NMR
Data for 9. IR (neat) 2962, 2933, 2908, 2870, 1969
1
(CDCl3, 400 MHz) d 1.21 (6H, s, 5-Me£2), 1.71 (6H, d,
J¼2.9 Hz, CvCvCMe2), 2.31 (3H, s, MeCvO), 2.34 (3H,
s, MeCvO), 4.98 (1H, septet, J¼2.9 Hz, CvCvCH), 6.56
(1H, s, CHvC); 13C NMR (CDCl3, 100 MHz) d 20.3 (2C, q,
9-C), 25.9 (q, 1-C), 28.4 (2C, q, 5-Me), 33.0 (q, 1-C), 38.0
(s, 5-C), 96.9 (d, 6-C), 98.7 (s, 8-C), 143.0 (s, 3-C), 151.9 (d,
4-C), 198.1 (s, CvO), 200.1 (s, 7-C), 205.2 (s, CvO); MS
m/z (rel. intensity) 220 (Mþ, 5), 205 (18), 111 (10), 43 (100),
41 (13). HRMS Found: m/z 220.1432. Calcd for C14H20O2;
M, 220.1464.
(CvCvC), 1717, (CvO), 1624 (CvC) cm21; H NMR
(CDCl3, 90 MHz) d 1.27 (6H, s, 2-Me£2), 1.68 (6H, d,
J¼2.6 Hz, CvCvCMe2), 1.69–2.04 (2H, m, CH2), 2.32
(2H, t, J¼7.5 Hz, COCH2), 2.61 (2H, dt, J¼2.2, 9.2 Hz,
vCCH2), 5.38 (1H, septet, J¼2.6 Hz, CHvCvC), 5.99
(1H, t, J¼2.2 Hz, CHvC); 13C NMR (CDCl3, 22.5 MHz) d
20.5 (t), 20.8 (2C, q, 6-C), 28.3 (2C, q, 2-Me), 34.0 (t), 37.2
(s), 41.0 (t), 97.3 (s, 5-C), 98.8 (d, 3-C), 135.5 (s, sCv),
148.0 (d, 1-C), 199.2 (s, 4-C), 206.0 (s, CvO); MS m/z (rel.
intensity) 204 (Mþ, 25), 189 (100), 186 (22), 171 (48), 161
(35), 148 (31), 137 (27), 134 (67), 133 (45), 119 (27), 105
(27), 95 (45), 91 (31), 79 (23), 77 (24), 67 (32), 55 (33), 43
(20), 41 (55), 38 (23). HRMS Found: m/z 204.1506. Calcd
for C14H20O; M, 204.1515.
5.3. Photochemistry of 1–6
5.3.1. Photochemistry of 1. A solution of 1 (800 mg,
4.55 mmol) in hexane (400 cm3) was degassed with argon
and then irradiated for 6 h using a 100 W high-pressure
mercury lamp with a pyrex jacket. After evaporation of the
solvent, the photoproducts were separated by medium-
pressure silica gel chromatography using 2.5% ether–
hexane as an eluent to give (Z)-2-(2,2-dimethyl-3,4-
pentadienylidene)cyclopentanone (7: 64 mg, 8%) and
10,10-diemthyl-2-methylene-3-oxatricyclo[7.1.0.04,8]deca-
4(8)-ene (8: 201 mg, 25%).
Data for 10. IR (neat) 2953, 2943, 2916, 2855, 1703
1
(CvC), 1680 (CvC) cm21; H NMR (CDCl3, 90 MHz) d
0.76 (3H, s, 10-Me), 1.19 (3H, s 10-Me), 1.20 (1H, d,
J¼8.8 Hz, CH), 1.57 (1H, d, J¼8.8 Hz, CH), 1.70 (6H, s,
vCMe2), 1.70–1.96 (2H, m, CH2), 2.23–2.47 (4H, m,
CH2CH2); 13C NMR (CDCl3, 22.5 MHz) d 15.5 (q), 16.6
(q), 18.8 (q), 19.5 (t), 22.8 (d), 23.4 (d), 25.1 (s, 10-C), 26.6
(q), 30.4 (t), 31.8 (t), 104.8 (s, vC), 108.7 (s, vC), 141.0 (s,
O–Cv), 147.9 (s, O–Cv); MS m/z (rel. intensity) 204
(Mþ, 90), 203 (28), 189 (100), 161 (37), 148 (27), 134 (58),
133 (36), 119 (27), 105 (27), 91 (25), 55 (21), 41 (32).
HRMS Found: m/z 204.1492. Calcd for C14H20O; M,
204.1515.
Data for 7. IR (neat) 1953 (CvCvC), 1715, (CvO), 1623
1
(CvC) cm21; H NMR (CDCl3, 90 MHz) d 1.31 (6H, s,
5-Me£2), 1.71–2.05 (2H, m, CH2), 2.34 (2H, t, J¼7.1 Hz,
COCH2), 2.62 (2H, dt, J¼1.6, 7.1 Hz, vCCH2), 4.77 (2H,
d, J¼6.6 Hz, CvCvCH2), 5.71 (1H, t, J¼6.6 Hz,
CHvCvC), 5.99 (1H, t, J¼1.6 Hz, CHvC); 13C NMR
(CDCl3, 22.5 MHz) d 20.5 (t), 28.3 (2C, q, 2-Me), 34.0 (t),
35.9 (s, 2-C), 41.1 (t), 77.1 (t, 5-C), 99.4 (d, 3-C), 136.0 (s,
vC), 147.2 (d, 1-C), 206.2 (s), 206.4 (s); MS m/z (rel.
intensity) 176 (Mþ, 25), 175 (21), 161 (100), 119 (23), 105
(51), 91 (29), 55 (25), 41 (28), 38 (24). HRMS Found: m/z
176.1230. Calcd for C12H16O; M, 176.1202.
Data for 11. IR (neat) 1734 (CvO), 1640 (CvC) cm21; 1H
NMR (CDCl3, 90 MHz) d 0.97 (3H, s, 5-Me), 1.20 (3H, s,
5-Me), 1.45 (3H, s, vCMe), 1.49 (1H, d, J¼5.3 Hz, CH),
1.67 (3H, s, vCMe), 1.67–2.43 (7H, m, including CH as a
doublet of J¼5.3 Hz at 2.21 ppm); 13C NMR (CDCl3,
22.5 MHz) d 18.6 (q), 18.8 (q), 19.0 (q), 19.2 (t), 24.1 (q),
26.7 (s, 5-C), 31.8 (d, 1-C), 31.9 (t), 34.6 (d, 4-C), 38.4 (t),
56.5 (s, 2-C), 121.1 (s, vC), 133.7 (s, vC), 221.0 (s,
CvO); MS m/z (rel. intensity) 204 (Mþ, 11), 161 (47), 148
(45), 133 (100), 105 (21), 91 (22), 41 (24). HRMS Found:
m/z 204.1506. Calcd for C14H20O; M, 204.1515.
Data for 8. IR (neat) 1702 (CvC) cm21; 1H NMR (CDCl3,
90 MHz) d 0.86 (3H, s, 10-Me), 1.16 (3H, s, 10-Me), 1.29
(1H, d, J¼8.5 Hz), 1.66 (d, J¼8.5 Hz), 1.71–2.47 (6H, m,
CH2CH2CH2), 4.21 (1H, d, J¼0.9 Hz, vCH), 4.52 (1H, d,
J¼0.9 Hz, vCH); 13C NMR (CDCl3, 22.5 MHz) d 14.9 (q),
19.6 (t), 24.0 (d), 25.5 (s, 10-C), 26.7 (q), 27.1 (d), 30.2 (t),
31.7 (t), 88.9 (t, vCH2), 106.2 (s, vC), 146.8 (s, O–Cv),
154.0 (s, O–Cv); MS m/z (rel. intensity) 176 (Mþ, 78), 175
(42), 161 (100), 135 (30), 121 (20), 119 (21), 105 (31), 91
(26), 55 (24), 43 (26), 41 (20). HRMS Found: m/z 176.1198.
Calcd for C12H16O; M, 176.1202.
Data for 12. IR (neat) 1736 (CvO), 1628 (CvC) cm21; 1H
NMR (CDCl3, 90 MHz) d 0.91 (3H, s, 5-Me), 1.28 (3H, s,
5-Me), 1.45 (3H, s, vCMe), 1.60 (3H, s, vCMe), 1.68 (1H,
d, J¼5.4 Hz, CH), 1.92–2.55 (7H, m, including CH as a
doublet of J¼5.4 Hz at 1.99 ppm); 13C NMR (CDCl3,
22.5 MHz) d 17.9 (t), 18.2 (q), 18.6 (t), 19.4 (t), 24.9
(q), 28.8 (s, 5-C), 32.6 (d, 1-C), 36.2 (t), 36.5 (d, 4-C), 36.8
(t), 55.6 (s, 2-C), 123.8 (s, vC), 130.7 (s, vC), 217.2
(s, CvO); MS m/z (rel. intensity) 204 (Mþ, 10), 161 (50),
148 (41), 133 (100), 105 (23), 43 (57), 39 (24), 36 (29).
HRMS Found: m/z 204.1475. Calcd for C14H20O; M,
204.1515.
5.3.2. Photochemistry of 2. A solution of 2 (830 mg,
4.07 mmol) in hexane (400 cm3) was degassed with argon
and then irradiated for 6 h using a 100 W high-pressure
mercury lamp with a pyrex jacket. After evaporation of the