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was conducted at 408 in THF, with a JASCO PU-980 pump, a JASCO UVDEC-100-III UV detector, and Shodex
A-802 (pore size: 20 ä) or A-803 (pore size: 100 ä) columns at a flow rate of 1.0 ml/min. A molecular weight
calibration curve was obtained by using a series of polystyrene standards (Tosoh Co., Japan).
Methyl 4-(1,1-Dimethoxymethyl)benzoate (12). A soln. of 4-formylbenzoic acid (11) (7.5g, 50 mmol) in
MeOH (50 ml) was treated with HC(OMe)3 (11.0 ml, 100 mmol) and conc. H2SO4 (2 g). After stirring for 12 h
at 808, the mixture was concentrated and poured into 10% aq. NaHCO3 soln. The org. layer was extracted with
Et2O, washed with sat. aq. NaCl soln., dried (MgSO4), and evaporated. The oily residue was purified by
distillation (92 938, 2 mm) to give 12 as a colorless oil (9.45g, 90%). 1H-NMR (300 MHz): 8.05( d, J 8.5,
2 arom. H); 8.03 (d, J 8.5, 2 arom. H); 5.44 (s, CH(OMe)2); 3.92 (s, CO2Me); 3.33 (s, CH(OMe)2). 13C-NMR
(75 MHz): 167.1; 143.2; 130.4; 129.8; 127.1; 102.6; 52.9; 52.4. Anal. calc. for C11H14O4 (210.23): C 62.85, H 6.71;
found: C 62.75, H 6.74.
4-{1-[(Trimethylsilyl)methyl]ethenyl}benzaldehyde (7). Powdered CeCl3 ¥ 7 H2O (12 g, 45mmol) was dried
at 1408 for 4 h under reduced pressure (1 mm). Under an argon atmosphere, anh. THF (100 ml) was added, and
the resulting suspension was stirred for 12 h at r.t. The white slurry obtained was cooled to À788 and dropwise
treated with Me3SiCH2SiCl (prepared from Me3SiCH2Cl (7.0 ml, 50 mmol) and Mg (1.5 g, 70 mmol) in Et2O
(30 ml)). The creamy-colored suspension was stirred at À788 for 1 h, treated with 12 (2.1 g, 10 mmol), and
stirred for an additional 2 h. The mixture was allowed to warm to r.t., stirred for 12 h, cooled to 08, and slowly
quenched by dropwise addition of H2O. The mixture was extracted with Et2O, washed with brine, and dried
(MgSO4). Evaporation of the solvent in vacuo led to crude 13, which was dissolved in THF (90 ml) and aq.
pyridinium p-toluenesulfonate (PPTS) soln. (1m, 10 ml). The mixture was stirred for 3 h at r.t., washed with
brine, and dried (MgSO4). The solvent was evaporated in vacuo and the crude product was purified by CC
1
(hexane) to yield 7 (58%) as a colorless oil. IR (neat): 2954, 1701, 1605, 1250, 842. H-NMR (300 MHz): 9.99
(s, CHO); 7.82 (d, J 8.3, 2 arom. H); 7.52 (d, J 8.3, 2 arom. H); 5.24 (s, 1 H, CCH2); 5.00 (s, 1 H, CCH2);
2.04 (s, SiCH2); À0.10 (s, SiMe3). 13C-NMR (75MHz): 192.1; 149.3; 146.1; 135.6; 130.0; 127.2; 113.1; 26.3; À1.1.
Anal. calc. for C13H18OSi (218.37): C 71.50, H 8.31; found: C 71.47, H 8.22.
4-{3-[(Trimethylsilyl)methyl]but-3-enyloxy}benzaldehyde (8). To an iced soln. of 16 (1.68 g, 10.6 mmol), p-
hydroxybenzaldehyde 17 (1.34 g, 11.0 mmol), and Ph3P (3.01 g, 11.4 mmol) in THF (40 ml) was added a toluene
soln. of diethyl 4,4'-azodicarboxylate (DEAD) (40%, 5.0 g, 11.5 mmol) diluted with THF (15 ml). The mixture
was stirred at r.t. for 2 h. The solvent was evaporated, the residue was dissolved in hexane/AcOEt 3 :1 and
filtered. The filtrate was concentrated, and the crude product was purified by FC (hexane/AcOEt 3 :1) to yield 8
(1.67 g, 60%) as a colorless oil. IR (neat): 3060, 1682, 1251, 1159. 1H-NMR (300 MHz): 9.87 (s, CHO); 7.82
(d, J 8.8, 2 arom. H); 6.99 (d, J 8.8, 2 arom. H); 4.69 (s, 1 H, CCH2); 4.66 (s, 1 H, CCH2); 4.15( t, J 6.98,
CH2O); 2.47 (t, J 6.98, CCCH2CH2); 1.6 (s, CH2Si); 0.05(SiMe 3). 13C-NMR (75MHz): 191.1; 164.3; 143.6;
132.3; 130.2; 115.1; 109.4; 67.4; 37.6; 27.6; À1.0. Anal. calc. for C15H22O2Si (262.14): C 68.65, H 8.45; found:
C 68.60, H 8.48.
3-[(Trimethylsilyl)methyl]but-3-enyl 4-Formylbenzoate (9). This compound was prepared from 16 (1.58 g,
10 mmol), 11 (2.61 g, 11.0 mmol), Ph3P (3.01 g, 11.4 mmol), and DEAD (40%, 5.0 g, 11.5 mmol) according to
1
the procedure described for the synthesis of 8. IR (neat): 2957, 1715, 1635, 1273, 1108. H-NMR (300 MHz):
10.01 (s, CHO); 8.19 (d, J 8.7, 2 arom. H); 7.95( d, J 8.7, 2 arom. H); 4.72 (s, 1 H, CCH2); 4.65( s, 1 H,
CCH2); 4.47 (t, J 6.87, CH2O); 2.44 (t, J 6.87, CCCH2CH2); 1.60 (s, CH2Si); 0.05(SiMe 3). 13C-NMR
(75MHz): 192.0; 164.3; 143.4; 139.4; 136.6; 130.5; 129.8; 109.7; 64.1; 37.4; 27.2; À1.0. Anal. calc. for C15H22O3Si
(290.43): C 66.17, H 7.64; found: C 66.15, H 7.68.
{4-[(Dimethoxymethyl)phenyl]}(methoxy)dimethylsilane (20). To 1-bromo-4-(dimethoxymethyl)benzene
(19) (3.70 g, 16 mmol) in THF (80 ml) was slowly added BuLi (1.6m in hexane, 16 mmol, 10 ml) at À788 over
30 min. Stirring was continued for 1 h at À788, and (MeO)2SiMe2 (2.73 ml, 20 mmol) was added to the above
suspension. The resulting mixture was stirred for 1 h at À788, allowed to warm to r.t., and stirred for 12 h. The
mixture was concentrated in vacuo, diluted with anh. Et2O (40 ml), filtered through Celite, and concentrated in
vacuo. The crude product was purified by distillation to yield 20 (2.23 g, 58%) as a colorless oil. B.p. 90 928
(2 mm Hg). IR (neat): 2954, 2830, 1450, 1353, 1254, 1190, 1098, 1056, 984, 828, 784. 1H-NMR (300 MHz): 7.58
(d, J 7.0, 2 arom. H); 7.47 (d, J 7.0, 2 arom. H); 5.39 (s, CH(OMe)2); 3.43 (s, SiOMe); 3.34 (s, CH(OMe)2);
0.38 (s, SiMe3). 13C-NMR (75 MHz): 139.7; 138.0; 133.7; 126.5; 103.5; 53.1; 51.0; À2.0. Anal. calc. for C12H20O3Si
(240.37): C 59.96, H 8.39; found: C 59.91, H 8.35.
[2-(4-Bromophenyl)prop-2-enyl]trimethylsilane (23). Powdered CeCl3 ¥ 7 H2O (33.5g, 90 mmol) was dried
at 1408 for 4 h under reduced pressure (1 mm). Under an argon atmosphere, anh. THF (160 ml) was added at
r.t. and the resulting suspension was stirred for 12 h. The white slurry obtained was cooled to À788.
Me3SiCH2MgCl (prepared from Me3SiCH2Cl (12.7 g, 100 mmol) and Mg (2.7 g, 110 mmol) in Et2O (50 ml)) was