Dry diethyl ether (100 ml) was added to magnesium powder
(0.51 g, 21.0 mmol) and a crystal of iodine under nitrogen and
the mixture cooled to 0 ЊC. 3-(Trifluoromethyl)benzyl bromide
(1.0 g, 4.2 mmol) dissolved in dry diethyl ether (25 ml) was
added dropwise to the stirred mixture over 1 h. Chlorotrimeth-
ylsilane (0.53 ml, 4.2 mmol) in dry diethyl ether (25 ml) was
then added to the stirred mixture at 0 ЊC over 1 h. The reaction
was allowed to warm to room temperature and saturated
ammonium chloride solution added. The diethyl ether layer was
separated and dried over anhydrous magnesium sulfate.
Removal of the diethyl ether and short-path distillation of the
oil gave 3-(trifluoromethyl)benzyltrimethylsilane (0.67 g, 69%);
δH 7.26–7.08 (4 H, m, 2-, 4-, 5-, 6-H), 2.08 (2 H, s, PhCH2), 0.00
[9 H, s, Si(CH3)3]; δC 142.50 (CF3), 130.52 (C-3), 129.46 (C-4),
124.89 (C-2), 124.85 (C-5), 124.03 (C-6), 123.99 (C-1), 65.03
(CH2SiMe3), 0.00 [Si(CH3)3]; νmax/cmϪ1: 3030m, 2919s, 1676m,
1331s (Found: Mϩ, 232.0872. Calc. for C11H15SiF3: M,
232.0895).
yield; δH 5.82 (1 H, dd, J9,10 5.9, J9,8 2.6, 9-H), 5.60 (1 H, d, 10-
H), 3.40 (1 H, dd, JCH,OH 13.9, JOH,CF 7.0, OH), 3.15 (1 H, dddd,
J7,bridge 10.8, J7,bridge 3.2, 7-H), 3.07 (1 H, d, J7,8 7.7, 8-H), 2.95 (1
H, dddd, J3,bridge 12.1, J3,7 7.6, 3-H), 2.19 (1 H, d, J2,3 7.3, 2-H),
1.80–1.34 (6 H, m, cyclopentane ring Hs), 1.12 (2 H, t,
CH2OH); δC 153.66, 138.34, 125.96, 123.63, 66.59, 57.74, 49.20,
39.55, 29.67, 29.89, 28.06, 26.82, 14.97 (Found: Mϩ, 244.1074.
Calc. for C13H15OF3: M, 244.0997).
1-Trimethylsilylmethyl-11-(trifluoromethyl)tetracyclo-
[6.3.0.02,11.03,7]undec-9-ene, endo isomer 10. Despite extensive
chromatography, the sample (14%) still contained trace
amounts of 11 by GC. δH 5.84 (1 H, dd, J9,10 5.9, J9,8 2.6, 9-H),
5.69 (1 H, d, 10-H), 3.17 (1 H, dddd, J7,bridge 10.6, J7,bridge 3.3, 7-
H), 3.08 (1H, dd, J3,bridge 10.0, J3,7 8.4, 3-H), 2.88 (1 H, ddd, J8,7
7.0, J8,F 7.0, 8-H), 2.10 (1 H, d, J2,3 7.0, J2,F 7.0, 2-H), 1.92–1.27
(6 H, m, cyclopropane ring Hs), 1.57 (2 H, s, CH2SiMe3), 0.10 (3
H, s, SiMe), 0.07 (3 H, s, SiMe), 0.04 (3 H, s, SiMe); δC 137.43,
126.72, 126.63, 61.14, 57.70, 49.08, 39.83, 29.39, 30.21, 27.14,
26.54, 14.14, 1.04; m/z 300 (Mϩ, 11%).
3-[3-(Trifluoromethyl)benzyldimethylsilyl]prop-1-ene 19. This
bichromophore was synthesised as outlined above with the
Grignard reagent being treated with allylchlorodimethylsilane.
δH 7.35–7.17 (4 H, m, 2Ј-, 4Ј-, 5Ј-, 6Ј-H), 5.77 (1 H, ddt, J2,1a
16.1, J2,1b 11.0, J2,3 8.0, 2-H), 4.90 (1 H, m, 1a-H), 4.86 (1 H, m,
J1b,3 1.1, 1b-H), 2.18 (2 H, s, PhCH2), 1.55 (2 H, dt, 3-H), 0.08
(3 H, s, SiMeA), 0.01 (3 H, s, SiMeB); δC 141.24 (CF3), 134.53,
134.34, 131.45, 128.66, 124.71, 121.01 (C-1Ј, C-2Ј, C-3Ј, C-4Ј,
C-5Ј C-6Ј), 113.77 (C-1), 113.40 (C-2), 25.29 (PhCH2), 22.62
(C-3), Ϫ3.99 [Si(CH3)2]; νmax/cmϪ1 3078 (arene C-H), 2918
exo-Isomer 11. Despite extensive chromatography, the sample
(6%) still contained small amounts of 10 by GC. δH 5.79 (1 H,
dd, J9,10 5.9, J9,8 2.6, 9-H), 5.66 (1 H, d, 10-H), 3.25 (1 H, m,
J7,bridge 7.5, J7,bridge 3.1, 7-H), 3.08 (1 H, m, J3,bridge 10.5, 3-H),
2.81 (1 H, dd, J8,F 7.0, 8-H), 2.05 (1 H, d, J2,F 7.0, 2-H), 1.90-
1.23 (6 H, m, cyclopropane ring Hs), 1.56 (2 H, s, CH2SiMe3),
0.10 (3 H, s, SiMe), 0.07 (3 H, s, SiMe), 0.04 (3 H, s, SiMe); δC
137.82, 126.92, 60.42, 59.82, 49.91, 41.15, 30.76, 30.23, 30.16,
27.10, 17.06, 1.48, 0.46; m/z 300 (Mϩ, 8%).
(C-H), 1677 (C᎐C), 1331 (C᎐Si) (Found Mϩ, 258.1048. Calc.
endo-1-Trimethylsilyloxy-11-(trifluoromethyl)tetracyclo-
᎐
for C13H17SiF3: M, 258.1051).
[6.3.0.02,11.03,7]undec-9-ene 12. Compound 12 was prepared in
67% yield; δH 5.66 (1 H, dd, J9,8 3.0, 9-H), 5.49 (1 H, d, J10,9 5.9,
10-H), 3.16 (1 H, m, J7,bridge 9.2, J7,bridge 4.6, 7-H), 2.92 (1 H, dd,
J3,bridge 10.0, J3,7 8.5, 3-H), 2.36 (1 H, d, J8,7 7.0, 8-H), 1.90 (1 H,
br s, 2-H), 1.60–1.10 (6 H, m, cyclopentane ring Hs), 0.10 [3 H,
s, Si(CH3)] and Ϫ0.04 [6 H, s, Si(CH3)2]; δC 136.40, 125.71,
116.43, 60.47, 58.22, 48.54, 29.51, 29.29, 26.69, 1.86, 0.74
(Found: Mϩ, 302.1317. Calc. for C15H21SiOF3: M, 302.1314).
1-Hydroxy-2-trifluoromethyl-endo-6-acetoxytricyclo-
Synthesis of 3-(phenoxydimethylsilyl)prop-1-ene. Phenol (0.70
g, 7.4 mmol) and triethylamine (0.75 g, 7.4 mmol) were dis-
solved in dry dichloromethane, and stirred under an atmos-
phere of nitrogen at 0 ЊC. Allylchlorodimethylsilane (1.0 g, 7.4
mmol) was dissolved in dry dichloromethane (10.0 ml) and
added dropwise over 30 min to the former solution. The result-
ing mixture was allowed to warm to room temperature and
stirred overnight. The mixture was then rotary evaporated. The
residue was washed with light petroleum (bp 40–60 ЊC) and
filtered. The solvent was evaporated from the filtrate to give an
oil which was purified by flash chromatography (1.3 g, 90.2%).
δH 7.20–6.85 (5 H, m, 2Ј-, 3Ј-, 4Ј-, 5Ј-, 6Ј-H), 5.82 (1 H, ddt, J2,1a
17.6, J2,1b 10.0, J2,3 7.6, 2-H), 4.96 (1 H, ddd, J1a,1b 6.0, J1a,3 1.6,
1a-H), 4.92 (1 H, ddd, J1b,3 1.6, 1b-H), 1.77 (2 H, d, 3-H), 0.00
(6 H, SiMe2); δC 133.36, 129.57, 121.72, 120.24 (1Ј-, 2Ј-, 3Ј-, 4Ј-,
5Ј-, 6Ј-C), 114.52 (1-C), 113.50 (2-C), 24.58 (3-C), 0.00 (SiCH3),
Ϫ1.70 (SiCH3); νmax/cmϪ1 2958m, 1596m, 1252s (Found: Mϩ,
192.0962. Calc. for C11H16SiO2: M, 192.0970).
[3.3.0.02,8]oct-3-ene 16. Compound 16 was prepared in 40%
yield; mp 80–82 ЊC; δH 5.93 (2 H, br s, 3-H, 4-H), 5.33 (1 H, ddd,
J6,7 7.0, J6,7Ј 9.5, 6-H), 3.49 (1 H, d, J5,6 5.5, 5-H), 2.43 (1 H, d,
J8,7Ј 5.5, 8-H), 2.43 (1 H, dd, J7,7Ј 14.7, 7-H), 2.02 (3 H, s, CH3),
1.47 (1 H, ddd, 7Ј-H), (signal for ᎐OH not clearly discerned); δC
170.34, 132.43, 125.13, 125.06, 79.60, 57.36, 30.88, 30.84, 26.80,
20.84; νmax(Nujol)/cmϪ1 3413m, 1736s, 1246s, 1045s, 735s
(Found: C, 52.12; H, 4.29%; Mϩ, 248.0590. Calc. for
C11H11F3O3: C, 53.23; H, 4.47; M, 248.0660).
1-Hydroxymethyl-2-trifluoromethyl-endo-6-acetoxytricyclo-
[3.3.0.02,8]oct-3-ene 17. Compound 17 was prepared in 53%
yield; δH 5.81 (2 H, br s, 3-, 4-H), 5.15 (1 H, ddd, J6,7Ј 8.1, J6,7
5.5, 6-H), 3.48 (1 H, d, J5,6 7.0, 5-H), 2.40 (1 H, ddd, J7,7Ј 13.6,
7-H), 2.05 (1 H, d, J8,7 6.6, 8-H), 2.01 (3 H, s, CH3OCO), 1.63
(2 H, s, CH2OH), 1.63–1.57 (1 H, m, 7Ј-H), (signal for ᎐OH
not clearly discerned); δC 170.46, 133.86, 125.80, 81.32, 80.83,
65.88, 61.41, 53.95, 51.55, 30.06, 28.06, 26.50, 20.88, 15.29
(Found: Mϩ, 262.0824. Calc. for C12H13O3F3; M, 262.0813).
1-Trimethylsilylmethyl-2-trifluoromethyl-endo-6-acetoxytri-
cyclo[3.3.0.02,8]oct-3-ene 18. Despite extensive chromatography,
the sample (11.6%) still contained trace amounts of unknown
impurities by GC; δH 5.78 (1 H, d, J4,3 5.5, 4-H), 5.73 (1 H, dd,
J3,5 1.1, 3-H), 5.15 (1 H, ddd, J6,7Ј 9.0, J6,7 7.0, 6-H), 3.11 (1 H, d,
J5,6 5.0, 5-H), 2.37 (1 H, ddd, J7,7Ј 14.5, 7-H), 2.00 (3 H, s,
CH3OCO), 1.87 (1 H, d, J8,7 5.5, 8-H), 1.61 (1 H, dd, 7Ј-H), 1.43
(2 H, s, CH2SiMe3), 0.11 (3 H, s, SiMe), 0.09 (3 H, s, SiMe), 0.08
(3 H, s, SiMe); δC 171.08, 133.53 (d, J4,F 9.2, C-4), 126.99,
126.59, 80.78 (d, J6,F 7.3, C-6), 57.58 (d, J5,F 5.5, C-5), 29.92,
27.52, 26.11, 21.49, 14.92, 0.00; m/z 316 (Mϩ 10%).
3-[3-(Trifluoromethyl)phenoxydimethylsilyl]prop-1-ene 20. 3-
(Trifluoromethyl)phenol (2.0 g, 12.3 mmol) and distilled tri-
ethylamine (1.2 g, 12.3 mmol) were dissolved in dry dichloro-
methane (35 ml) and cooled to 0 ЊC under a nitrogen atmos-
phere. To this yellow solution was added dropwise over 30 min a
solution of allylchlorodimethylsilane (1.7 g, 12.3 mmol) in dry
dichloromethane (15 ml). The solution was allowed to warm to
room temperature and the dichloromethane removed by rotary
evaporation. The residue was extracted with light petroleum
(bp 60–80 ЊC) (100 ml) and purified by flash chromatography
(1.9 g, 59.1%). δH 7.27–6.91 (4 H, m, 2Ј-, 4Ј-, 5Ј-, 6Ј-H), 5.71 (1
H, ddt, J2,1a 16.9, J2,1b 10.3, J2,3b 9.9, 2-H), 4.88 (1 H, m, J1a,3 1.5,
J1a,1b 7.0, 1a-H), 4.79 (1 H, ddd, J1b,3 1.5, 1b-H), 1.69 (1 H, d,
J3a,3b 8.1, 3a-H), 1.49 (1 H, dd, 3b-H), 0.21 (6 H, s, SiMe2); δC
155.41 (CF3), 132.86, 130.10, 123.49, 118.43 (C-1Ј, C-2Ј, C-3Ј,
C-4Ј, C-5Ј, C-6Ј), 114.96 (C-1), 113.40 (C-2), 24.45 (C-3), 0.00
(SiCH3) Ϫ1.72 (SiCH3) (Found Mϩ, 260.0844. Calc. for
C12H15SiOF3: M, 260.0844).
Photoproducts
3-Dimethylsilyl-8-(trifluoromethyl)tetracyclo[5.4.0.01,8.05,11]-
undec-9-ene 24. Compound 24 was prepared in 27% yield; δH
5.70 (1 H, d, J9,10 5.9, 9-H), 5.41 (1 H, dd, J10,11 2.9, 10-H), 2.25
endo-1-Hydroxymethyl-11-(trifluoromethyl)tetracyclo-
[6.3.0.02,11.03,7]undec-9-ene 7. Compound 7 was prepared in 90%
J. Chem. Soc., Perkin Trans. 2, 1998
217