(5 cm3), dried (MgSO4) and evaporated. Purification of the
resulting oil by neutral alumina chromatography (petroleum
ether–dichloromethane, 1 : 2 as eluent) gave mono ester 20 as a
mixture of diastereoisomers (0.07 g, 44%): νmax(KBr disc)/cmϪ1
3420, 2982, 1720, 1609; δH (400 MHz; CDCl3) 1.08, 1.12, 1.16
and 1.26 (each 9 H, s, 4 × tBu), 1.29 (18 H, s, 2 × tBu), 3.47
(12 H, s, 3 × CH2CH2), 3.52 (6 H, s, 2 × OMe), 3.53 (3 H, s,
OMe), 4.88, 5.00 and 5.19 (each 1 H, br s, signals disappear on
addition of D2O, 3 × OH), 4.97 (1 H, s, MeO–CH), 4.98 (2 H, s,
2 × MeO–CH), 6.18, 6.25, 6.29, 6.38 (each 1 H, d, J 8.0,
4 × ArH), 6.53–6.57 (3 H, m, 3 × ArH), 6.67–6.69 (2 H, m,
2 × ArH), 6.73–6.76 (3 H, m, 3 × ArH), 6.86, 6.89 and 6.99
(each 1 H, d, J 2.0, 3 × ArH), 7.28–7.45 (25 H, m, 25 × ArH),
7.52–7.56 (5 H, m, 5 × ArH); DEPT135 NMR δC (100 MHz;
CDCl3) 29.8 (CH3), 30.0 (CH3), 30.1 (CH2), 30.2 (CH3), 30.5
(CH3), 30.6 (CH2), 57.8 (OCH3), 58.1 (OCH3), 77.6 (CH), 83.4
(CH), 83.5 (CH), 117.3 (CH), 117.6 (CH), 119.4 (CH), 119.5
(CH), 119.6 (CH), 121.9 (CH), 122.3 (CH), 127.8 (CH), 128.1
(CH), 128.3 (CH), 128.4 (CH), 128.6 (CH), 128.9 (CH), 129.0
(CH), 129.2 (CH), 129.4 (CH), 129.5 (CH), 132.5 (CH), 132.8
(CH), 132.9 (CH); FAB m/z (relative intensity) 598 (Mϩ, 13%),
121 (C8H9Oϩ, 100%), 57 (C4H9ϩ); m/z (EI) 593.3088 (Mϩ,
C41H42O4 requires 598.3083).
2 × CH3), 3.39 (4 H, s, 2 × CH2), 6.08–6.89 (6 H, br m, 6 ×
Ar-H), 7.24 and 7.33 (each 2 H, d, J 7.2, 2 × Ar-H) and 8.88
(2 H, s, 2 × OH) (signal disappears on addition of D2O);
δC (75.5 MHz; DMSO) 16.1 (CH3), 29.9 (CH2), 113.3, 119.3,
127.1, 131.5 and 132.1 (Ar-CH), 122.1, 127.5, 132.9, 136.6,
140.5, 145.1 and 153.6 (Ar-C); m/z (CI) 366 (Mϩ, 100%); m/z
366.1622 (Mϩ, C26H22O2 requires 366.1620).
5,6-Bis(3-tert-butyl-4-hydroxy-5-methylphenyl)acenaphthene 24
and 4,6-bis(3-tert-butyl-4-hydroxy-5-methylphenyl)-
acenaphthene 25
To a solution of 14 (0.112 g, 0.221 mmol) in dichloromethane
(10 cm3), under argon, at Ϫ78 ЊC a solution of boron tribromide
(0.44 cm3 of a 1 M solution in DCM) was slowly added, then the
temperature was allowed to increase to room temperature.
After 12 hours the reaction was quenched with 10% HCl solu-
tion (10 cm3); the product was evaporated, extracted into ethyl
acetate, washed with 10% HCl, dried (MgSO4) and evaporated.
The resulting solid (0.100 g) was purified by silica gel chrom-
atography (petroleum ether–ethyl acetate, 10 : 1 as eluent) to
yield diphenol 24 as the first fraction (0.024 g, 23%); δH (300
MHz; CDCl3) 1.17 [18 H, s, 2 × C(CH3)3], 2.21 (6 H, s,
2 × CH3), 3.49 (4 H, s, 2 × CH2), 4.55 (2 H, s, 2 × OH) (signal
disappears on addition of D2O), 6.55 (2 H, s, 2 × Ar-H), 7.02
(2 H, s, 2 × Ar-H), 7.37 (4 H, s, 4 × Ar-H); δC (75.5 MHz;
CDCl3) 16.5 (CH3), 29.7 [C(CH3)3], 30.5 (CH2), 34.4 [C(CH3)3],
119.5, 127.6, 129.6 and 133.1 (Ar-CH), 122.1, 133.8, 135.2,
137.0, 141.0, 145.9 and 151.1 (Ar-C); m/z (CI) 478 (Mϩ, 100), 57
(C4H9ϩ, 87%); m/z (EI) 478.2871 (Mϩ, C34H38O2 requires
478.2872). The second fraction was rearrangement product 25
(0.013 g, 12%), δH (300 MHz; CDCl3) 1.49 and 1.51 [each 9 H, s,
C(CH3)3], 2.33 and 2.36 (each 3 H, s, CH3), 3.40–3.57 (4 H, br s,
2 × CH2), 4.82 and 4.86 (each 1 H, s, OH) (signal disappears on
addition of D2O), 7.25–7.26 (1 H, m, Ar-H), 7.29–7.34 (1 H, br
m, Ar-H), 7.35–7.49 (4 H, br m, 4 × Ar-H), 7.53 (1 H, s, Ar-H)
and 7.91 (1 H, s, Ar-H); δC (75.5 MHz; CDCl3) 16.0 and 16.6
(CH3), 29.7 and 30.3 [C(CH3)3], 30.6 and 31.0 (CH2), 35.1
[C(CH3)3], 119.2, 119.6, 124.9, 127.2, 128.3, 129.1, 130.1 and
133.2 (Ar-CH), 123.4, 123.6, 130.3, 132.4, 134.6, 135.8, 136.1,
136.4, 139.1, 142.0, 145.0, 147.0, 152.3 and 152.6 (Ar-C); m/z
(CI) 478 (Mϩ, 80), 57 (C4H9ϩ, 100%); m/z (EI) 478.2863 (Mϩ,
C34H38O2 requires 478.2871).
4,6-Bis(3-tert-butyl-4-hydroxyphenyl)acenaphthene 21
A solution of bis(methyl ether) 13 (0.10 g, 0.21 mmol) in dry
dichloromethane (15 cm3) under argon at Ϫ78 ЊC was treated
with boron tribromide solution (0.21 cm3 of a 2.0 M solution in
dichloromethane, 0.421 mmol) (slow addition) and the mixture
allowed to warm to rt. After 12 h, the reaction was quenched
with 10% HCl; the product was partially evaporated, diluted
with ethyl acetate, washed with 10% HCl, dried (MgSO4)
and evaporated. The resulting solid was purified by silica gel
chromatography (petroleum ether–ethyl acetate, 100 : 1 as elu-
ent) to give diphenol 18 (0.044 g, 46%) which was identical to
that reported (vide supra) and rearrangement product 21
(0.022 g, 23%), mp 91 ЊC; λmax(Et2O)/nm 321.0 (ε/dm3 molϪ1 cmϪ1
12 061), 272 (30 397) and 212 (35 403); νmax/cmϪ1 (thin film)
3680–3160 (OH), 3020–2910 (CH3, CH2), 2890 (Ar–H), 1610
and 1500 (aromatic), 1470 (CH3), 1260 (C–OH), 1090 (C–O)
and 820 (para-substituted aromatic); δH (300 MHz; CDCl3) 1.45
and 1.47 [each 9 H, s, C(CH3)3], 3.40 and 3.43 (each 2 H, s,
CH2), 4.81 and 4.84 (each 1 H, s, OH) (signals disappear on
addition of D2O), 6.72 (1 H, d, J 8.3, Ar-H), 6.78 (1 H, d, J 7.9,
Ar-H), 7.26–7.36 (3 H, m, 3 × Ar-H), 7.40 (1 H, d, J 7.2,
Ar-H), 7.51 (1 H, br s, Ar-H), 7.53 and 7.54 (each 1 H, d, J 4.5,
Ar-H) and 7.85 (1 H, s, Ar-H); δC (75.5 MHz; CDCl3) 30.0 and
30.1 [C(CH3)3], 30.6 and 31.0 (CH2), 35.1 [C(CH3)3], 116.9,
117.2, 119.3, 119.5, 119.7, 126.6, 127.0, 128.5, 129.1 and 129.2
(Ar-CH), 130.3, 133.0, 135.3, 136.3, 136.4, 136.6, 139.1, 142.0,
145.1, 147.1, 153.9 and 154.2 (Ar-C); m/z (FAB) 450 (Mϩ,
100%); m/z (EI) 450.2564 (Mϩ, C32H34O2 requires 450.2559).
Acknowledgements
We thank the EPSRC for a studentship (to M. S., GR/
97311210) and are grateful to Professor V. Snieckus for
much useful advice on hindered biaryl coupling reactions and
Johnson Matthey for a generous loan of palladium acetate.
References
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5,6-Bis(4-hydroxy-3-methylphenyl)acenaphthene 23
To a solution of bis(methyl ether) 12 (0.27 g, 0.68 mmol) in dry
dichloromethane (10 cm3) under argon at Ϫ78 ЊC, boron tri-
bromide (1.4 cm3 of a 1 M solution in dichloromethane) was
added slowly, then the mixture was allowed to warm to room
temperature. After five hours the reaction was quenched with
10% HCl solution (10 cm3); the product was evaporated,
extracted into ethyl acetate, washed with 10% HCl, dried
(MgSO4) and evaporated. The crude product was then
recrystallised from diethyl ether–hexane to yield 23 (0.18 g,
73%) as a light brown solid, mp 203 ЊC (decomp.); λmax(EtOH)/
nm 315.0 (ε/dm3 molϪ1 cmϪ1 12 115), 238 (38 730) and 203.5
(48 038); νmax/cmϪ1 (KBr disc) 3460–3080 (OH), 3010–2930
(CH2, CH3), 1600 and 1500 (aromatic), 1430 (CH3, CH2), 1350
(OH), 1150 (C–O), 880 (isolated aromatic H) and 820 (para-
substituted ring); δH (300 MHz; DMSO) 1.61–2.01 (6 H, br s,
J. Chem. Soc., Perkin Trans. 1, 2001, 588–598
597