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Can. J. Chem. Vol. 81, 2003
50.4, 58.4,58.5, 81.8, 108.7, 111.2, 118.2, 118.8, 122.1,
124.8, 128.2, 130.2, 138.8, 142.7, 148.4, 148.7, 148.8. HR-
MS calcd. for C16H16O3 m/z: 256.10998; found: 256.10887.
Experimental
General procedure for the generation of benzynes in the
presence of ketone and aldehyde enolates
t-BuLi in hexane (7.95 mmol) was added dropwise to a
stirred solution of tetramethylpiperidine (7.95 mmol) in
anhyd THF (10 mL) under nitrogen at –40 °C. The mixture
was stirred for 10 min and a solution of ketone (3.18 mmol)
in THF (5 mL) was added. This was followed by the addi-
tion of solution of halobenzene (3.18 mmol) in THF (5 mL).
The reaction mixture was stirred at –40 °C for 5 h. An aque-
ous ammonium chloride solution was added and the result-
ing solution was extracted with ethyl acetate. The combined
organic extracts were washed with brine, dried over Na2SO4,
and concentrated under reduced pressure. The residue was
purified by chromatography on silica gel with EtOAc–hex-
anes to give the benzocyclobutenol.
6-Methoxy-cis-2-ethyl-1-phenylbenzocyclobutenol (11a)
1
Yield: 36%. H NMR (CDCl3, 200 MHz) δ: 1.13 (t, J =
7.4 Hz, 3H), 1.61–1.99 (m, 2H), 2.65 (s, 1H), 3.45 (t, J =
8.0 Hz, 1H), 3.71 (s, 3H), 6.80 (t, J = 8.4 Hz, 1H), 7.21–
7.49 (m, 6H). 13C NMR (CDCl3, 50 MHz) δ: 13.5, 24.1,
58.2, 60.1, 83.5, 115.5, 116.2, 126.1, 128.2, 128.4, 132.2,
146.1, 150.1, 152.1, 156.2. HR-MS calcd. for C17H18O2 m/z:
254.13074; found: 254.13061.
6-Methoxy-1-(3,4-dimethoxyphenyl)benzocyclobutenol (11b)
1
Yield: 55%. H NMR (CDCl3, 200 MHz) δ: 3.40 (s, 1H),
3.42 (s, 2H), 3.63 (s, 3H), 3.80 (s, 6H), 6.75 (m, 3H), 6.90
(d, J = 8.8 Hz, 1H), 7.08 (s, 1H), 7.22 (t, J = 8.8 Hz, 1H).
13C NMR (CDCl3, 50 MHz) δ: 50.1, 55.7, 56.6, 80.9, 108.9,
110.6, 113.0, 116.2, 117.6, 131.2, 133.2, 137.1, 143.6,
148.0, 148.6, 157.3. HR-MS calcd. for C17H18O4 m/z:
286.1205; found: 286.1190.
1-Phenylbenzocyclobutenol (7a) (11)
1
Yield: 32%. H NMR (CDCl3, 200 MHz) δ: 3.38 (s, 1H),
3.60 (ABq, 2H), 7.20–7.58 (m, 9H). 13C NMR (CDCl3,
50 MHz) δ: 50.4, 82.1, 122.3, 124.8, 126.3, 128.1, 128.3,
128.9, 130.3, 134.4, 142.7, 144.1, 149.7. HR-MS calcd. for
C14H12O m/z: 196.0888; found: 196.0861.
Tricyclo (4,3,0,0) hydroxy-1-nonadecatriene-2,4,6 (12a)
(12d)
1
cis-2-Methyl-1-phenylbenzocyclobutenol (7b)
Yield: 65%, mp 56 to 57 °C. H NMR (CDCl3, 200 MHz)
1
Yield: 35%. H NMR (CDCl3, 200 MHz) δ: 1.51 (d, J =
δ: 1.01–1.29 (m, 1H), 1.56–1.89 (m, 4H), 2.10 (m, 1H), 1.65
(brs, 1H), 3.51 (t, J = 1.6 Hz, 1H), 7.11–7.39 (m, 4H). 13C
NMR (CDCl3, 50 MHz) δ: 25.1, 29.1, 36.3, 57.6, 89.8,
121.4, 123.6, 128.5, 130.2, 144.4, 148.3.
8.0 Hz, 3H), 2.61 (s, 1H), 3.81 (q, J = 8.0 Hz, 1H), 7.21–
7.45 (m, 9H). 13C NMR (CDCl3, 50 MHz) δ: 15.2, 54.1,
82.9, 122.8, 123.5, 126.9, 127.9, 128.0, 128.1, 128.6, 129.2,
130.3, 144.8, 149.0, 149.1. HR-MS calcd. for C15H14O m/z:
210.1045; found: 210.1035.
2-Phenylcyclopentanone (13a) (12e)
1H NMR (CDCl3, 200 MHz) δ: 1.81–2.61 (m, 6H), 3.51
(t, J = 8.0 Hz, 1H), 7.21–7.49 (m, 5H). 13C NMR (CDCl3,
50 MHz) δ: 22.1, 32.1, 38.5, 56.1, 128.1, 129.4, 129.9,
140.1.
cis-2-Ethyl-1-phenylbenzocyclobutenol (7c)
1
Yield: 36%. H NMR (CDCl3, 200 MHz) δ: 1.18 (t, J =
7.3 Hz, 3H), 1.73–1.98 (m, 2H), 2.57 (s, 1H), 3.59 (t, J =
7.7 Hz, 1H), 7.21–7.46 (m, 9H). 13C NMR (CDCl3,
50 MHz) δ: 13.0, 24.1, 61.4, 83.2, 122.7, 124.0, 126.1,
127.8, 128.9, 130.2. HR-MS calcd. for C16H16O m/z:
224.1201; found: 224.1191.
Tricyclo (4,4,0,0) hydroxy-1-dodecatriene-2,4,6 (12b)
(12a–12c)
Yield: 55%, mp 106–108 °C. 1H NMR (CDCl3, 200 MHz)
δ: 1.11–2.11 (m, 8H), 2.29 (brs, 1H), 3.39 (t, J = 7.6 Hz,
1H), 7.10–7.35 (m, 4H). 13C NMR (CDCl3, 50 MHz) δ:
18.0, 18.4, 24.3, 32.1, 54.2, 79.6, 121.6, 123.7, 128.1, 129.7,
146.1, 149.9. HR-MS calcd. for C12H14O m/z: 174.1045;
found: 174.1071.
cis-1,2-Diphenylbenzocyclobutenol (7d)
Yield: 52%, mp 144–146 °C. 1H NMR (CDCl3, 200 MHz)
δ: 2.70 (s, 1H), 5.41 (s, 1H), 6.96–7.37 (m, 12H), 7.71 (m,
2H). 13C NMR (CDCl3, 50 MHz) δ: 49.7, 75.9, 126.7, 127.3,
127.5, 127.7, 127.9, 128.2, 128.3, 128.5, 128.8, 129.5,
129.7, 137.8, 142.2, 144.7, 147.3. HR-MS calcd. for
C20H16O m/z: 272.1201; found: 272.1101.
2-Phenylcyclohexanone (13b) (12e)
Yield: 20%. 1H NMR (CDCl3, 200 MHz) δ: 1.71–2.61 (m,
4-Methoxyphenylbenzocyclobutenol (7e) (11)
8H), 3.61 (dd, J = 8.0, 16.0 Hz, 1H), 7.11–7.49 (m, 5H). 13
C
1
Yield: 41%. H NMR (CDCl3, 200 MHz) δ: 2.71 (brs,
NMR (CDCl3, 50 MHz) δ: 25.9, 28.4, 35.7, 42.8, 58.0,
127.5, 128.9, 129.1, 139.3, 210.0. HR-MS calcd. for
C12H14O m/z: 174.1045; found: 174.1057.
1H), 3.58 (ABq, 2H), 3.77 (s, 3H), 6.86 (d, J = 8.8 Hz, 2H),
7.21–7.49 (m, 6H). 13C NMR (CDCl3, 50 MHz) δ: 50.2,
55.9, 81.8, 114.2, 122.3, 124.8, 127.7, 128.2, 130.2, 136.4,
142.7, 149.8, 159.5. HR-MS calcd. for C15H14O2 m/z:
226.0994; found: 226.0983.
Tricyclo (4,5,0,0) hydroxy-1-tridecatriene-2,4,6 (12c)
(12a–12c)
3,4-Dimethoxyphenylbenzocyclobutenol (7f) (11)
Yield: 42%. H NMR (CDCl3, 200 MHz) δ: 2.88 (brs,
1H), 3.57 (ABq, 2H), 3.82 and 3.83 (2s, 6H), 6.73 (d, J =
8.3 Hz, 1H), 6.88 (dd, J = 8.3, 1.3 Hz, 1H), 7.09 (d, J =
8.3 Hz, 1H), 7.32 (m, 4H). 13C NMR (CDCl3, 50 MHz) δ:
Yield: 82%. 1H NMR (CDCl3, 200 MHz) δ: 1.31–2.21 (m,
10H), 2.70 (s, 1H), 3.41 (dd, J = 4.5, 10.0 Hz, 1H), 7.10–
7.31 (m, 4H). 13C NMR (CDCl3, 50 MHz) δ: 24.8, 28.1,
31.4, 32.6, 36.8, 60.8, 84.2, 121.4, 123.5, 128.0, 129.7,
146.3, 149.8.
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© 2003 NRC Canada