Synthesis of Stable 2-Silanaphthalenes
J. Am. Chem. Soc., Vol. 121, No. 49, 1999 11343
pentane, 4.9 mmol) to afford 4b as a white powder. 4b: mp 208-212
°C; 1H NMR (CDCl3) δ -0.06 (s, 18H), 0.10 (s, 18H), 0.25 (s, 27H),
2.38 (s, 2H), 2.42 (dd, J ) 16.8, 4.8 Hz, 1H), 2.50 (dd, J ) 16.8, 4.4
Hz, 1H), 5.03(br m, 1H), 6.30 (d, J ) 14.0 Hz, 1H), 6.70 (s, 2H),
7.10-7.14 (m, 4H), 7.29 (d, J ) 14.0 Hz, 1H); 13C NMR (CDCl3) δ
1.11 (q), 1.46 (q), 5.40 (q), 17.36 (t), 22.23 (s), 22.91 (d), 125.96 (d),
126.39 (d), 126.55 (d), 127.09 (s), 127.76 (d), 130.74 (d), 132.19 (d),
135.07 (s), 135.33 (s), 146.68 (s), 146.77 (d), 151.78 (s); 29Si NMR
(CDCl3) δ -42.82, 0.69, 1.44, 1.54. HRMS (EI, 70 eV): found m/z
768.4097, calcd for C39H76Si8 ([M]+) 768.4101. Anal. Calcd for C39H76-
Si8: C, 60.85; H, 9.95. Found: C, 60.69; H, 9.73.
were calculated, assuming that 1a was pure. 1a: mp 151-155 °C (dec);
1H NMR (C6D6) δ 0.14 (s, 36H), 0.16 (s, 18H), 1.53 (s, 1H), 2.61 (br
s, 1H), 2.72 (br s, 1H), 6.61 (br s, 1H), 6.73 (br s, 1H), 6.99 (ddd, J )
8.1, 6.9, 1.2 Hz, 1H), 7.20 (ddd, J ) 8.1, 6.9, 1.2 Hz, 1H), 7.24 (dd,
J ) 13.0, 2.2 Hz, 1H), 7.40 (d, J ) 2.2 Hz, 1H), 7.60 (d, J ) 8.1 Hz,
1H), 7.64 (d, J ) 8.1 Hz, 1H), 8.48 (d, J ) 13.0 Hz, 1H); 13C NMR
(C6D6, 126 MHz) δ 0.62 (q), 0.82 (q), 31.51 (d), 36.87 (d), 37.50 (d),
116.01 (d), 120.58 (d), 121.53 (d), 122.56 (d), 125.69 (s), 126.08 (d),
126.70 (d), 128.26 (s), 128.77 (d), 133.27 (d), 146.53 (s), 148.01 (s),
148.95 (d), 152.33 (s), 152.38 (s); 29Si NMR(C6D6, 54 MHz) δ 2.2,
2.5, 87.3; UV-vis (hexane) λmax 267 nm (ꢀ 2 × 104), 327 nm (ꢀ 7 ×
103), 387 nm (ꢀ 2 × 103). HRMS (EI, 70 eV): found m/z 694.3554
([M]+), calcd for C36H66Si7 694.3549. Anal. Calcd for C36H66Si7: C,
62.17; H, 9.56. Found: C, 60.97; H, 9.44.
Synthesis of 1b. Compound 1b was synthesized by the same
procedure as that for 1a. The use of 6b (216 mg, 0.254 mmol) and
t-BuLi (0.45 M in hexane, 3.0 mmol) gave 2-{2,6-bis[bis(trimethylsilyl)-
methyl]-4-[tris(trimethylsilyl)methyl]phenyl}-2-silanaphthalnene (1b)
( ∼50% yield estimated by NMR spectra). Recrystallization from
hexane gave small amount of 1b as a white powder. 1b: 1H NMR
(C6D6) δ 0.15 (s, 36H), 0.36 (s, 27H), 2.85 (s, 2H), 7.00 (ddd, J ) 8.2,
7.0, 1.2 Hz, 1H), 7.06 (s, 2H), 7.19 (dd, J ) 13.1, 2.2 Hz, 1H), 7.20
(ddd, J ) 8.2, 7.0, 1.2 Hz, 1H), 7.33 (d, J ) 2.2 Hz, 1H), 7.60 (d, J
) 8.2 Hz, 1H), 7.64 (d, J ) 8.2 Hz, 1H), 8.49 (d, J ) 13.1 Hz, 1H);
13C NMR (C6D6) δ 1.19 (q), 5.46 (q), 23.29 (s), 39.25 (s), 114.97 (d),
120.55 (d), 121.96 (d), 125.99 (d), 126.77 (d), 128.59 (s), 128.72 (s),
133.30 (d), 146.49 (s), 148.99 (d), 149.59 (s), 151.94 (s); 29Si NMR
(C6D6) δ 1.15, 2.18, 86.68.
Bromination of 4a. 4a (50 mg, 0.072 mmol) and NBS (13 mg,
0.073 mmol) were dissolved in CCl4 (10 mL) under dry air, and the
solution was stirred at 0 °C. After disappearance of 4a ( ∼5 days) the
solvent was evaporated, hexane (10 mL) was added, and the mixture
was filtered. Removal of the solvent afforded almost pure 2-{2,4,6-
tris[bis(trimethylsilyl)methyl]phenyl}-2-bromo-1,2-dihydro-2-silanaph-
thalene (6a) (48.5 mg, 87%) as white powder. As 6a gradually
decomposed in air to give TbtH, further purification was not performed.
6a: mp 168-176 °C dec; 1H NMR (C6D6, 500 MHz) δ 0.12 (s, 18H),
0.15 (s, 9H), 0.19 (s, 9H), 0.20 (s, 9H), 0.26 (s, 9H), 1.44 (s, 1H), 2.67
(br s, 1H), 2.70 (br s, 1H), 3.07 (d, J ) 16.2 Hz, 1H), 3.19 (d, J )
16.2 Hz, 1H), 6.47 (br s, 1H), 6.60 (br s, 1H), 6.61 (d, J ) 13.5 Hz,
1H), 6.87-7.06 (m, 5H); 13C NMR (C6D6, 126 MHz) δ 0.91 (q), 0.94
(q), 1.01 (q), 1.14 (q), 1.54 (q), 1.65 (q), 27.91 (t), 29.18 (d), 29.56
(d), 31.11 (d), 122.86 (d), 123.55 (s), 126.62 (d), 128.29 (d), 128.42
(d), 129.40 (d), 130.68 (d), 132.00 (d), 134.79 (s), 135.04 (s), 144.85
(d), 146.82(s), 152.84 (s), 153.46 (s); 29Si NMR (C6D6, 54 MHz) δ
-7.51, 1.68, 2.16, 2.30, 2.78. HRMS (FAB): found m/z 776.2819, calcd
for C36H6781BrSi7 ([M]+) 776.2790. Anal. Calcd for C36H67BrSi7: C,
55.69; H, 8.69; Br, 10.29. Found: C, 56.43; H, 9.01; Br, 7.71.
Bromination of 4b. Bromination of 4b was performed by the same
procedure as that for 4a. The use of 4b (200 mg, 0.260 mmol), NBS
(46.7 mg, 0.262 mmol) gave almost pure 2-{2,6-bis[bis(trimethylsilyl)-
methyl]-4-[tris(trimethylsilyl)methyl]phenyl-2-bromo-1,2-dihydro-2-si-
lanaphthalene (6b) (216 mg, 98%) as a white powder. 6b was also
Crystal Data of 1a. Formula C36H66Si7, M ) 695.52, monoclinic,
space group P21/c, a ) 12.762(6) Å, b ) 9.91(1) Å, c ) 34.67(1) Å,
â ) 96.58(3) °, V ) 4356(4) Å3, Z ) 4, Dc ) 1.060 g cm-3, R )
0.071 (Rw ) 0.047). Colorless and prismatic single crystals of 1a were
grown by the slow evaporation of its hexane solution. The intensity
data were collected on a Rigaku AFC7R diffractometer with graphite-
monochromated Mo KR radiation (λ ) 0.71069 Å) at 193 K. The
structure was solved by direct method with SHELXS-86, and refined
by the full-matrix least-squares method. All the non-hydrogen atoms
were refined anisotropically, and all hydrogen atoms were located by
calculation. The final cycles of the least-squares refinements were based
on 6018 observed reflections (I > 5.00σ|I|) and 388 variable parameters.
Reaction of 1a with Deuterium Oxide. To 1a (30 mg, 0.043 mmol
if pure) was added deuterium oxide (0.5 mL) and THF (2 mL). After
the solution was stirred for 10 min, the solvent was removed.
Purification by PTLC (hexane/chloroform ) 2:1) afforded 1-deuterio-
2-hydroxy-2-{2,4,6-tris[bis(trimethylsilyl)methyl]phenyl}-1,2-dihydro-
2-silanaphthalene (8) as a white powder (25.8 mg, 84%). As the D
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unstable in air. 6b: mp 192-198 °C dec; H NMR (C6D6) δ 0.19 (s,
18H), 0.28 (s, 18H), 0.32 (s, 27H), 2.84 (s, 2H), 3.02 (d. J ) 16.5 Hz,
1H), 3.18 (d, J ) 16.5 Hz, 1H), 6.63 (d, J ) 13.7 Hz, 1H), 6.88 (s,
2H), 6.88-6.97 (m, 4H), 7.06 (d, J ) 7.3 Hz, 1H); 13C NMR (C6D6)
δ 1.87 (q), 2.01 (q), 5.67 (q), 22.67 (s), 27.74 (d), 30.04 (d), 126.32
(s), 126.64 (d), 127.71 (d), 128.29 (d), 128.44 (d), 129.60 (d), 130.61
(d), 131.92 (d), 134.70 (s), 134.89 (s), 144.41 (d), 148.73(s), 152.81
(s); 29Si NMR (C6D6) δ -8.12, 1.06, 1.96, 2.48. HRMS (FAB): found
m/z 846.3199, calcd for C39H7579BrSi8 ([M]+) 846.3207. Anal. Calcd
for C39H75BrSi8: C, 55.19; H, 8.90; Br, 9.41. Found: C, 56.06; H,
8.83; Br, 8.74.
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content of the white powder was 70% (from H NMR), the net yield
Bromination of 3a. Bromination of 3a was performed by the same
procedure as that for 4a. The use of 3a (50 mg, 0.071 mmol) and NBS
(14.0 mg, 0.079 mmol) gave almost pure 2-{2,4,6-tris[bis(trimethyl-
silyl)methyl]phenyl}-2-bromo-1,2,3,4-tetrahydro-2-silanaphthalene (7a)
(56.7 mg, 100%) as a white powder. 7a was also unstable in air. 7a:
1H NMR (CDCl3) δ 0.02 (s, 9H), 0.05 (s, 9H), 0.06 (s, 18H), 0.10 (s,
9H), 0.11 (s, 9H), 1.36 (s, 1H), 1.50 (ddd, J ) 15.6, 10.8, 5.5 Hz, 1H),
1.72 (dt, J ) 14.8, 5.2 Hz, 1H), 2.05 (br s, 1H), 2.11 (br s, 1H), 2.77
(ddd, J ) 14.8, 10.8, 5.0 Hz, 1H), 2.83 (d, J ) 14.5 Hz, 1H), 2.92 (d,
J ) 14.5 Hz, 1H), 2.97 (dt, J ) 14.3, 5.6 Hz, 1H), 6.31 (br s, 1H),
6.44 (br s, 1H), 7.14-7.20 (m, 4H); 13C NMR (CDCl3) δ 0.39 (q),
0.80 (q), 0.98 (q), 1.03 (q), 1.53 (q), 20.42 (t), 28.64 (d), 29.14 (d),
29.53 (t), 30.50 (t), 30.72 (d), 122.38 (d), 124.53 (s), 125.99 (d), 126.67
(d), 127.44 (d), 127.68 (d), 130.54 (d), 135.98 (s), 139.89 (s), 146.29
(s), 151.85 (s), 152.77 (s).
Synthesis of 1a. To a solution of 6a (334 mg, 0.43 mmol) in hexane
(10 mL) was added t-BuLi (0.59 M in hexane, 0.045 mmol) with
stirring. The solution was transferred into a Pyrex tube and degassed
and sealed. After opening the tube in the glovebox filled with argon,
the solvent was slowly removed. Generation of 2-{2,4,6-tris[bis-
(trimethylsilyl)methyl]phenyl}-2-silanaphthalene (1a) was confirmed
by NMR spectra ( ∼80%), although only small amount of pure 1a
was obtained by careful recrystallization from hexane. This crude
mixture was used for further reactions without purification, and yields
of 8 was 59%. The following data were obtained for the sample which
was prepared by the reaction of 1a with H2O. 8: mp 169-171 °C dec;
1H NMR (CDCl3, 500 MHz) δ -0.07 (s, 9H), -0.05 (s, 9H), 0.04 (s,
18H), 0.05 (s, 9H), 0.09 (s, 9H), 1.31 (s, 1H), 1.67 (s, 1H), 2.42 (br s,
1H), 2.46 (br s, 1H), 2.48 (d, J ) 16.8 Hz, 1H), 2.55 (d, J ) 16.8 Hz,
1H), 6.25 (br s, 1H), 6.36 (d, J ) 14.0 Hz, 1H), 6.37 (br s, 1H), 7.08-
7.14 (m, 4H), 7.27 (d, J ) 14.0 Hz, 1H); 13C NMR (CDCl3, 126 MHz)
δ 0.54 (q), 0.73 (q), 0.77 (q), 0.89 (q), 1.14 (q), 24.77 (t), 28.27 (d),
28.54 (d), 30.42 (d), 122.08 (d), 125.78 (d), 125.99 (s), 127.06 (d),
127.51 (d), 130.48 (d), 130.55 (d), 133.23 (d), 135.10 (s), 136.00 (s),
144.99 (s), 146.03 (d), 151.51 (s), 151.97 (s); 29Si NMR (CDCl3, 54
MHz) δ -11.70, 1.61, 1.78, 2.13. HRMS (FAB): found m/z 712.3628
([M]+), calcd for C36H68OSi7 712.3655. Anal. Calcd for C36H68OSi7:
C, 60.59; H, 9.60. Found C, 60.29; H, 9.65.
Reaction of 1a with Methanol. To 1a (30 mg, 0.043 mmol if pure)
was added methanol (0.5 mL) and THF (2 mL). After the solution was
stirred for 10 min, the solvent was removed. Purification by PTLC
(hexane/chloroform ) 2:1) afforded 2-methoxy-2-{2,4,6-tris[bis(tri-
methylsilyl)methyl]phenyl}-1,2-dihydro-2-silanaphthalene (9) as a white
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powder (22.6 mg, 72%). 9: mp 162-164 °C; H NMR (CDCl3, 500
MHz) δ -0.10 (s, 9H), -0.07 (s, 9H), 0.03 (s, 18H), 0.05 (s, 9H),
0.08 (s, 9H), 1.29 (s, 1H), 2.34 (d, J ) 17.2 Hz, 1H), 2.47 (br s, 1H),
2.50 (br s, 1H), 2.55 (d, J ) 17.2 Hz, 1H), 3.32 (s, 3H), 6.22 (br s,
1H), 6.29 (d, J ) 14.0 Hz, 1H), 6.35 (br s, 1H), 7.08-7.14 (m, 4H),