A New Germanium-Based Linker
J . Org. Chem., Vol. 65, No. 17, 2000 5261
4-{2-[(P h e n yl-3-e t h a n on e )d im e t h ylge r m yl]e t h yl}-
p h en ol 8. A solution of n-BuLi (34.4 mL, 1.6M, 55 mmol) in
hexanes was added dropwise to a solution of 2-(3-bromphenyl)-
2-methyl-1,3-dioxolane53 (13.5 g, 55 mmol) in THF (100 mL)
at -78 °C. After being stirred for 20 min, the mixture was
transferred by cannula to a solution of chlorodimethylgermane
12 (2.85 g, 11 mmol) in toluene (50 mL) at -78 °C. The mixture
was then refluxed at 110 °C for 3 h. The sample was then
quenched with 1 N HCl (100 mL) and extracted with Et2O (3
× 100 mL). The organic fractions were collected, dried (Mg-
SO4), and concentration in vacuo to give a yellow oil. To this
oil was added acetone (100 mL), H2O (5 mL), and PPTS, (200
mg), and the mixture was refluxed for 16 h at 67 °C before
being concentrated in vacuo. The resulting yellow paste was
dissolved in EtOAc (100 mL) and washed successively with
H2O (100 mL), 10% NaHCO3 (100 mL), and H2O (100 mL).
The organic layer was dried (MgSO4) and concentrated in
vacuo. Purification by flash chromatography (petrol/EtOAc,
4/1) gave aryldimethylgermane 8 as a yellow oil (1.62 g, 43%).
1H NMR (CDCl3) δ 0.39 (s, 6H), 1.26-1.31 (m, 2H), 2.61-2.68
(m, 2H), 2.61 (s, 3H), 4.72 (s, 1H), 6.71 (d, J ) 8.4, 2H), 7.01
(d, J ) 8.4, 2H), 7.43 (t, J ) 7.2, 1H), 7.91 (d, J ) 7.5, 1H),
7.89 (d, J ) 7.5, 1H), 8.01 (s, 1H); 13C NMR (CDCl3) δ 3.7 (q),
18.0 (t), 26.7 (q), 30.1 (t), 115.3 (d), 128.1 (d), 128.5 (d) 128.9
(d), 132.9 (d), 136.0 (s), 136.2 (s), 138.2 (d) 142.5 (s), 154.1 (s),
199.7 (s); IR (neat) 3390, 1680, 1260 cm-1; MS (TSP+) 362
(MNH4+); HRMS calcd for (MNa+) C18H22Ge70O2Na 363.0760,
found 363.0768.
4-Br om o-4′-m eth oxy Bip h en yl 21.102 Dimethyl sulfate
(1.7 mL, 18 mmol), 4-bromo-4′-hydroxybipenyl (3.028 g, 12
mmol), and LiOH‚H2O (765 mg, 18 mmol) were suspended in
THF (20 mL) and heated at 70 °C for 1 h. The resulting
mixture was partitioned between 1 M KOH and Et2O. The
organic layer was dried (MgSO4) and concentrated in vacuo,
and the resulting white solid was recrystallized (CH2Cl2/petrol)
to give methyl ether 21 as white needles (3.06 g, 97%). Mp
142-145 °C (CH2Cl2/petrol) [cf. 144-145 °C (EtOH-ben-
zene)102]; 1H NMR (CDCl3) δ 3.85 (s, 3H), 6.97 (d, J ) 8.9, 2H),
7.39-7.55 (m, 6H); 13C NMR (CDCl3) δ 55.4 (q), 114.3 (d), 120.8
(s), 128.0 (d), 128.3 (d), 131.8 (d), 132.5 (s), 139.7 (s), 159.4 (s);
MS (EI+) m/z 262 (M+).
4-[2-Dim eth yl-(4,4′-biph en ylm eth oxy)ger m yleth yl]ph en -
ol 9. A solution of n-BuLi (3.9 mL, 2.0M, 8.2 mmol) in hexanes
was added dropwise to a solution of biphenyl 21 (2.141 g, 8.14
mmol) in THF (20 mL) at -78 °C. This solution was trans-
ferred by cannula to a solution of chlorodimethylgermane 12
(0.422 g, 1.63 mmol) in toluene (15 mL) at -78 °C. The
resulting mixture was warmed to room temperature and
stirred for 16 h at this temperature before being refluxed for
6 h at 110 °C. After being quenched with 1 N HCl (100 mL),
the mixture was extracted with Et2O (3 × 200 mL), and the
combined organic extracts were dried (MgSO4). Purification
by flash chromatography (CH2Cl2) gave aryldimethylgermane
9 as a white solid (0.562 g, 85%). Mp 86-87 °C (petrol/EtOAc);
1H NMR (CDCl3) δ 0.42 (s, 6H), 1.28-1.35 (m, 2H), 2.66-2.73
(m, 2H), 3.83 (s, 3H), 5.03 (s, 1H), 6.75 (d, J ) 8.5, 2H), 7.00-
7.10 (m, 4H), 7.52-7.60 (m, 6H); 13C NMR (CDCl3) δ -3.6 (q),
18.1 (t), 30.2 (t), 55.4 (q), 114.3 (d), 115.2 (d), 126.3 (d). 128.2
(d), 129.0 (d), 133.7 (d), 136.9 (s), 139. (s), 140.8 (s), 153.5 (s),
159.1 (s); IR (Nujol) 3334, 1253, cm-1; MS (FAB+) m/z 408
(M+); HRMS calcd for C23H26Ge74O2 408.1144, found 408.1150.
4-{2-[(P h e n yl-4-e t h a n on e )d im e t h ylge r m yl]e t h yl}-
p h en yl Eth oxyeth yl Eth er 13 a n d 4-{2-[(P h en yl-4-eth a n -
on e)d im eth ylger m yl]eth yl}p h en yl Dibu tyl P h osp h on a te
23. A solution of ADDP (366 mg, 1.45 mmol) in benzene (2
mL) was added dropwise to a solution of ethoxy ethanol (30
mg, 0.29 mmol), phenol 7 (96 mg, 0.29 mmol), and PBu3 (0.35
mL, 1.5 mmol) in benzene (1 mL) at 0 °C over 10 min. After
being stirred for a further 30 min at 0 °C, the solution was
allowed to warm to room temperature and was stirred at this
temperature for a further 3 h, after which time the white
precipitate was removed by filtration and the filtrate was
concentrated in vacuo. Purification by flash chromatography
(petrol/EtOAc, 9/1) gave ethoxyethyl ether 13 as a colorless
1
oil (59 mg, 42%). H NMR (CDCl3) δ 0.37 (s, 6H), 1.24 (t, J )
7.2, 3H), 1.25-1.32 (m, 2H), 2.60 (s, 3H), 2.60-2.67 (m, 2H),
3.59 (q, J ) 7.0, 2H), 3.77 (t, J ) 5.2, 2H), 4.08 (t, J ) 5.2,
2H), 6.96 (d, J ) 8.9, 2H), 7.05 (d, J ) 9.0, 2H), 7.55 (d, J )
8.3, 2H), 7.89 (d, J ) 8.2, 2H); 13C NMR (CDCl3) δ -3.8 (q),
15.2 (q), 17.9 (t), 26.6 (q), 30.1 (t), 66.8 (t), 67.5 (d), 69.0 (d),
114.6 (d), 127.4 (d), 128.7 (d), 133.5 (d), 136.5 (s), 148.7 (s),
157.0 (s), 198.4 (s); IR (neat) 1684, 1245 cm-1; MS (CI+) m/z
417 (MH+). HRMS calcd for (MH+) C22H31Ge74O3 417.1485,
found 417.1502; and dibutylphosphonate 23 as a colorless oil
(15 mg, 10%). 1H NMR (CDCl3) δ 0.37 (s, 6H), 0.90 (t, J ) 7.0,
6H), 1.23-1.32 (m, 2H), 1.35-1.47 (m, 4H), 1.54-1.68 (m, 4H),
1.75-1.88 (m, 4H), 2.60 (s, 3H), 2.61-2.68 (m, 2H), 7.08 (s,
4H), 7.55 (d, J ) 8.2, 2H), 7.90 (d, J ) 8.3, 2H); 13C NMR
(CDCl3) δ -4.0 (q), 13.4 (q), 17.6 (t), 23.8 (t), 26.6 (q), 26.7 (t),
28.5 (t), 31.0 (t), 120.3 (d), 127.2 (d), 128.8 (d), 133.3 (d), 137.1
(s), 138.0 (s), 139.9 (s), 148.2 (s), 198.1 (s); 31P NMR (CDCl3) δ
58.54 (s); MS (FAB+) m/z 505 (MH+); HMRS calcd for (MH+)
C
26H40Ge74O3P 505.1927, found 505.1939.
4-{2-[(P h e n yl-4-e t h a n on e )d im e t h ylge r m yl]e t h yl}-
p h en yl Eth oxyeth yl Eth er 13. Meth od II. A solution of
TMAD (520 mg, 2.86 mmol) in benzene (10 mL) was added
dropwise to a solution of ethoxy ethanol (30 mg, 0.29 mmol),
phenol 7 (96 mg, 0.29 mmol), and PBu3 (0.35 mL, 1.5 mmol)
in benzene (15 mL). After being stirred for 16 h, the resulting
gel was diluted with EtOAc/CH2Cl2 (1/1) whereupon a white
precipitate formed. This precipitate was removed by filtration,
and the filtrate was concentrated in vacuo. Purification by
flash chromatography (petrol/EtOAc, 9/1) gave ethoxyethyl
ether 13 as a colorless oil (343 mg, 87%). Spectroscopic data
as above.
4-{2-[(P h e n yl-4-e t h a n on e )d im e t h ylge r m yl]e t h yl}-
p h en yl Eth er Resin 14. A solution of TMAD (270 mg, 1.5
mmol) in benzene (10 mL) was added dropwise to a mixture
of Argogel (735 mg, 0.36 mmol),73 phenol 7 (370 mg, 1.1 mmol),
and PBu3 (0.45 mL, 1.8 mmol) in benzene (20 mL). After being
stirred for 16 h, the resulting gel was diluted with EtOAc/
CH2Cl2 (1/1), and the resin was separated by filtration and
washed with DMF (3 × 30 mL), MeOH (3 × 30 mL), THF (3
× 30 mL), Et2O (3 × 30 mL), and CH2Cl2 (3 × 30 mL). The
resin was then dried under high vacuum (0.7 mmHg, 80 °C)
for 3 days to give a free-flowing yellow resin 14 (835 mg, ∼0.43
mmol g-1; N.B.: loading was determined by mass balance of
acetophenone following cleavage using TFA).1H MAS NMR
(CH2Cl2) δ 0.41 (s, 6H), 1.30-1.38 (m, 2H), 2.59 (s, 3H), 2.62-
2.66 (m, 2H), 3.42-3.79 (polymer CHs), 6.91 (d, J ) 8.9, 2H),
7.10 (d, J ) 9.0, 2H), 7.60 (d, J ) 8.3, 2H), 7.93 (d, J ) 8.2,
2H); IR (Nujol) 1682, 1511 cm-1
.
Dan syl Hydr azon e of 4-{2-[(P h en yl-4-eth an on e)dim eth -
ylger m yl]eth yl}p h en ol (24). Aryldimethylgermane 7 (37 mg,
0.11 mmol) and dansyl hydrazine (31 mg, 0.12 mmol) were
dissolved in DMF/AcOH (1.0 mL, 1/1) and the resulting
solution stirred for 5 h. The solvent was then removed in vacuo
and the resulting oily residue purified by flash chromatography
(petrol/EtOAc, 1/1) to yield dansyl hydrazone 24 as a fluores-
1
cent yellow oil (51 mg, 92%). H NMR (CDCl3) δ 0.31 (s, 6H),
1.17-1.24 (m, 2H), 2.11 (s, 3H), 2.53-2.60 (m, 2H), 2.87 (s,
6H), 5.28 (s, 1H), 6.68 (d, J ) 8.5, 2H), 6.94 (d, J ) 8.5, 2H),
7.18 (d, J ) 7.6, 1H), 7.31 (d, J ) 8.2, 2H), 7.44 (d, J ) 8.2,
2H), 7.58 (t, J ) 8.5, 2H), 8.14 (s, 1H), 8.46 (d, J ) 7.3, 1H),
8.55 (t, J ) 8.2, 2H); 13C NMR (CDCl3) δ -3.8 (q), 13.2 (q).
18.0 (t), 30.1 (t), 45.5 (q), 115.1 (d), 115.3 (d), 119.3 (d), 123.5
(d), 125.6 (d), 128.4 (d), 128.9 (d), 129.7 (s), 129.9 (s), 131.1
(d), 131.3 (d), 133.1 (d), 133.7 (s), 136.4 (s), 137.0 (s), 143.5 (s),
152.0 (s), 153.7 (s); MS (FAB+) m/z 592 (MH+). HRMS calcd
for (MH+) C30H36Ge70N3O3S 588.1720, found 588.1675.
4-{2-[(P h e n yl-3-e t h a n on e )d im e t h ylge r m yl]e t h yl}-
p h en yl Eth oxyeth yl Eth er 15. A solution of TMAD (510 mg,
3.0 mmol) in toluene (20 mL) was added dropwise to a solution
of ethoxy ethanol (270 mg, 3.0 mmol), phenol 8 (684 mg, 2.0
mmol), and PBu3 (0.7 mL, 3.0 mmol) in toluene (20 mL). After
being stirred for 16 h, the mixture was diluted with EtOAc/
(102) Harley-Mason, J .; Mann, F. G. J . Chem. Soc. 1940, 1379-
1385.