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T.A. Spencer et al. / Tetrahedron 66 (2010) 4441e4451
5.1.23. 1-(1,2,3,4-Tetrahydro-1,4-methano-naphthalen-9-exo-yl)-
propan-2-one (39). Prepared as described above: 1H NMR 7.17e7.06
(m, 4H), 3.13e3.12 (m, 2H), 2.42e2.40 (d, J¼7.2 Hz, 2H), 2.32e2.27
(t, J¼7.8 Hz,1H), 2.17 (s, 3H),1.92e1.88 (m, 2H),1.27e1.15 (m, 2H);13C
NMR 208.1,148.6,125.7,120.7, 54.4, 46.4, 43.5, 30.4, 24.3. Anal. Calcd
for C14H16O: C, 83.96; H, 8.05. Found: C, 83.82; H, 7.97.
of 44 in 5 mL of CH2Cl2. The resulting slurry was stirred for 20 min at
0 ꢀC and filtered through a fritted funnel. The alumina pad was
washed several times with CH2Cl2. The total contact time of the or-
ganic material with alumina was 40 min. Evaporation of the filtrates
gave 0.720 g (58%) of 41 as a pale yellow oil: 1H NMR 7.30e7.22 (m,
4H), 3.61e3.58 (d of d, 2H), 2.04e1.95 (m, 2H), 1.73e1.66 (m, 2H),
1.44e1.32 (m, 4H); (lit.54 1H NMR (CCl4) 7.2 (s, 4H), 3.47 (m, 2H),
2.5e0.7 (m, 8H)); 13C NMR: 217.7, 142.8, 127.9, 123.7, 52.9, 32.1, 24.7.
5.1.24. 9-endo-(2-Methyl-allyl)-1,2,3,4-tetrahydro-1,4-methano-
naphthalene (10). As in the preparation of 9, 3.55 g (32.2 mmol) of
potassium tert-butoxide, 12.77 g (32.0 mmol) of methyltriphenyl-
phosphonium iodide, and 2.30 g (0.010 mol) of 38 gave 7.35 g of
orange oil, which after treatment with 3.0 mL of iodomethane, gave
2.20 g of yellow oil, which was chromatographed with hexanes to
give 1.47 g (74%) of colorless oily 10: 1H NMR 7.32e7.22 (m, 4H),
4.82 (m, 1H), 4.64 (m, 1H), 3.25 (s, 2H), 2.35e2.30 (t, J¼7.5 Hz, 1H),
2.14e2.10 (m, 2H), 1.86e1.82 (overlapping 3H s and 2H m),
1.35e1.33 (m, 2H); 13C NMR 146.3, 145.5, 125.8, 122.0, 110.5, 59.1,
47.6, 36.1, 27.7, 23.2. Anal. Calcd for C15H18: C, 90.85; H, 9.15. Found:
C, 90.64; H, 9.01.
5.1.30. Conversion of 44 to 41 plus 1,2,3,4,4a,9a-hexahydro-fluoren-
9-one (45). According to a modification of a procedure by Lombardo
et al.,31 2.51 g (13.5 mmol) of 44 was left adsorbed on a Brockmann I
activated, acidic alumina column (175 g) in hexane for 12 min. The
column was then eluted with 19:1 hexanes/EtOAc to give 0.051 g
(2%) of 41 containing a small amount of impurities by NMR. During
the collection of fractions warming of the bottom of the column was
observed. Further elution gave 1.11 g (44%) of a 2:1 mixture of 41 and
45 as a pale yellow oil: 1H NMR 7.76 (d, 1H, 45), 7.58 (5, 1H, 45), 7.46
(d, 1H, 45), 7.37 (t, 1H, 45), 7.30e7.22 (m, 4H, 41), 3.61e3.58 (d of d,
2H, 41), 3.43e3.36 (m, 1H, 45), 2.80e2.74 (m, 1H, 45), 2.17e2.06 (m,
2H, 45), 2.04e1.95 (m, 2H, 41),1.83e1.15 (m, 6H, 45þm, 6H, 41) (lit.55
1H NMR for 45 7.80e7.27 (m, 4H), 3.42e3.34 (m, 1H), 2.79e2.73 (m,
1H), 2.17e2.04 (m, 2H), 1.81e1.16 (m, 6H)).
5.1.25. 9-exo-(2-Methyl-allyl)-1,2,3,4-tetrahydro-1,4-methano-
naphthalene (11). As in the preparation of 10, 0.96 g (4.82 mmol) of
39 afforded 1.79 g of yellow oil, which was chromatographed with
hexane to give 0.70 g (73%) of 11 as a colorless oil: 1H NMR
7.21e7.10 (m, 4H), 4.81e4.78 (m, 2H), 3.13e3.11 (m, 2H), 2.16e2.11
(t, J¼7.5 Hz, 1H), 2.05e1.99 (m, 2H), 1.80 (s, 3H), 1.23e1.17 (m, 2H);
13C NMR 149.4, 144.7, 125.5, 120.6, 111.0, 57.7, 46.2, 37.3, 24.4, 22.8.
Anal. Calcd for C15H18: C, 90.85; H, 9.15. Found: C, 90.57; H, 9.26.
5.1.31. Conversion of 44 to 4b,6,7,8,9,9a-hexahydro-benzo[3,4]cyclo-
buta[1,2]cyclohepten-5-one (46) and 41. According to a modification
of a procedure by Lombardo et al.,31 to a stirred suspension of 36 g of
Brockmann I activated, acidic alumina (old reagent) in 150 mL of
CH2Cl2 at 0 ꢀC was added a solution of 0.72 g (3.91 mmol) of 44 in
5 mL of CH2Cl2. The slurry was stirred for 20 min at 0 ꢀC and filtered
through a fritted funnel. The alumina pad was washed several times
with CH2Cl2. The total contact time of the organic material with
alumina was 35 min. Evaporation of the filtrates gave 0.51 g (71%) of
a 1.5:1 mixture of 46 and 41 as a colorless viscous oil: 1H NMR
7.32e7.08 (m, 4H, 46 and m, 4H, 41), 4.55 (d, 1H, 46), 3.91e3.83 (m,
1H, 46), 3.62e3.59 (d of d, 2H, 41), 2.62e1.27 (m, 8H, 46 and m, 8H,
41); (lit.31 1H NMR (CDCl4) for 46: 7.23e6.84 (m, 4H), 4.35 (d, 1H),
3.75 (m, 1H), 2.63e1.16 (m, 8H)). Then, according to a procedure by
Lombardo et al.,31 0.16 g (0.84 mmol) of p-toluenesulfonic acid
monohydrate was added to a solution of 0.373 g (2.00 mmol) of the
1.5:1 mixture of 46:41 in 45 mL of benzene, and the resulting solu-
tionwas heatedat refluxfor 5 min, and then allowed tocooltort. The
benzene was evaporated and the resulting residue was dissolved in
100 mL of ether, washed with 5% NaHCO3 solution to neutral pH and
brine, dried, andpassed through aneutralaluminaplug. Evaporation
of the filtrate gave 0.313 g of 41 (73% conversion of 46 to 41) as
a yellow oil containing traces of impurities by NMR.
5.1.26. 5,6,7,8,9,9a-Hexahydro-benzo[3,4]cyclobuta[1,2]cyclohepten-
4b-ol (42). According to the procedure of Adam et al.,32 cyclo-
heptanone and bromobenzene were converted in 90% yield to 42 as
a yellow solid, which was recrystallized from hexanes to give col-
orless 42: mp 95.5e97.5 ꢀC (lit.32 mp 95 ꢀC); 1H NMR 7.31e7.14 (m,
4H), 3.51e3.46 (d of d, 1H), 2.35 (s, 1H), 2.21e2.14 (m, 2H), 1.93 (t,
1H), 1.85e1.62 (m, 4H), 1.54e1.38 (m, 3H); (lit.32 1H NMR 7.50e7.10
(4H), 3.35 (m, 1H), 2.30 (s, 1H), 2.20e1.10 (m, 10H)); 13C NMR 149.4,
145.9, 129.4,127.7,123.2, 120.9, 83.9, 60.6, 36.4, 32.2, 31.0, 27.8, 24.4.
5.1.27. 5,6,7,8-Tetrahydro-4bH-benzo[3,4]cyclobuta[1,2]cycloheptene
(43). According to a procedure by Caubere et al.,53 a mixture of
7.60 g (40.4 mmol) of 42, 0.437 g (2.29 mmol) of p-toluenesulfonic
acid monohydrate, and 280 mL of benzene was heated at reflux for
20 h. The mixture was cooled to rt, washed with 5% NaHCO solu-
tion, water, and brine, dried, filtered, and evaporated to give 6.56 g
(95%) (lit.52 80%) of 43 as a brown oil, which solidified in the freezer
at ꢁ15 ꢀC: 1H NMR 7.26e7.12 (m, 4H), 6.07e6.02 (t of d, 1H),
3.82e3.76 (d of d, 1H), 2.33e2.24 (m, 3H), 2.12e2.04 (m, 1H),
1.96e1.88 (m, 1H), 1.59e1.20 (m, 3H); (lit.53 1H NMR
d
(CCl4)
5.1.32. Tricyclo[6.4.1.02,7]trideca-2(7),3,5-trien-13-ylidene-acetic
acid ethyl ester (47). As in the preparation of 31, 2.67 g (66.7 mmol)
of NaH (60% dispersion in mineral oil) and 11.9 mL (59.9 mmol) of
triethylphosphonoacetate, plus 5.47 g (29.4 mmol) of 41 gave 5.61 g
(75%) of 47 as a pale yellow oil. A small amount of this oil was
rechromatographed (19:1 hexanes/EtOAc) to give a colorless oil,
which crystallized to afford colorless 47: mp 41e41.5 ꢀC; 1H NMR
7.22e7.14 (m, 4H), 5.87e5.86 (m, 1H), 4.80e4.78 (d of d, 1H),
4.25e4.17 (q of d, 2H), 3.91e3.89 (d of d, 1H), 2.28e2.18 (m, 1H),
1.85e1.76 (m, 2H), 1.71e1.63 (m, 1H), 1.48e1.36 (m, 2H), 1.32 (t, 3H),
1.26e1.07 (m, 2H); 13C NMR 170.4, 166.5, 147.1, 144.3, 127.6, 127.3,
123.3, 122.9, 112.9, 59.9, 51.9, 47.3, 36.3, 33.3, 25.0, 24.4, 14.6. Anal.
Calcd for C17H20O2: C, 79.65; H, 7.86; Found: C, 79.56; H, 7.87.
7.35e6.77 (m, 4H), 6.07e5.78 (t of d, 1H), 3.95e3.50 (m, 1H),
2.50e0.85 (m, 8H)); 13C NMR 148.7, 145.9, 143.4, 127.9, 127.7, 122.2,
119.4, 118.5, 52.5, 32.8, 30.7, 29.3, 28.9.
5.1.28. 5,6,7,8,9,9a-Hexahydro-benzo[3,4]cyclobuta[1,2]-cyclo-
hepten-4,5b-oxirene (44). According to the procedure of Lombardo
et al.,31 43 was epoxidized to afford 92% of oily 44: 1H NMR
7.39e7.12 (m, 4H), 3.83e3.78 (d of d, 1H), 3.54e3.52 (m, 1H),
2.29e2.21 (m, 1H), 2.17e2.11 (m, 1H), 2.00e1.91 (m, 1H), 1.87e1.47
(m, 5H); (lit.31 1H NMR
d (CCl4) 7.40e6.86 (m, 4H), 3.90e3.48 (m,
1H), 3.43e3.23 (m, 1H), 2.48e1.18 (m, 8H)); 13C NMR 147.7, 143.9,
129.8, 128.2, 121.8, 121.5, 70.4, 59.4, 51.5, 28.9, 26.8, 25.2, 17.3.
5.1.29. Tricyclo[6.4.1.02,7]trideca-2(7),3,5-trien-13-one (41). Accord-
ing to a modification of a procedure by Lombardo et al.,31 to a stirred
suspension of 61.2 g of Brockmann I activated, acidic alumina in
250 mL of CH2Cl2 at 0 ꢀC was added a solution of 1.24 g (6.66 mmol)
5.1.33. Tricyclo[6.4.1.02,7]trideca-2(7),3,5-trien-13-exo-yl-acetic acid
ethyl ester (48). According to a modification of a procedure by
Adams et al.,51 a mixture of 2.01 g (7.85 mmol) of 47 and 0.041 g
(0.180 mmol) of PtO2 in 50 mL of EtOAc was stirred at rt under an