B. Guintchin, S. Bienz / Tetrahedron 59 (2003) 7527–7533
7531
to Section 4.3.1, 6 (92 mg, 0.26 mmol) gave a mixture of
10a and 11a (91 mg, 0.26 mmol, ratio 93:7, 100%) as a
CHCl3). IR: 3084w, 3062w, 3028m, 2961s, 2927m, 2894m,
2823m, 1602w, 1493m, 1453m, 1247m, 1120s, 1101s, 838s,
812m, 758m, 699s. H NMR of 10b: 7.37–7.14 (m, 10
1
yellow
oil.
Following
data
from
mixture.
[a]D¼þ28.7^0.2 (c¼1.1, CHCl3). IR: 3030w, 2957s,
2925s, 2856s, 1618w, 1454m, 1376w, 1247m, 1120s,
971w, 837s, 756m, 700m. 1H NMR of 10a: 7.37–7.24
(m, 5 arom. H); 5.48 (dq, J¼9.1, 1.7 Hz, CHCSi); 4.34
(dd, J¼7.4, 4.2 Hz, PhCH); 3.64, 3.44 (AB of ABX,
JAB¼10.5 Hz, JAX¼7.4 Hz, JBX¼4.2 Hz, PhCHCH2O);
3.31 (s, MeO); 3.26, 3.20 (AB, J¼12.9 Hz, SiCH2O);
2.59–2.43 (m, CHCHCSi); 1.65 (d, J¼1.7 Hz, MeCSi);
1.35–1.14 (m, MeCH2CH2CH2, 6 H); 0.90 (d, J¼6.6 Hz,
MeC); 0.88 (t, J¼7.2 Hz, MeCH2); 0.07 (s, Me2Si). 3J
(1H, 29Si)¼8.3 Hz. 13C NMR of 10a: 147.6 (d, SiCCH);
139.7 (s, SiC); 131.3 (s, arom. C); 128.2 (d, 2 arom. C);
127.6 (d, arom. C); 126.9 (d, 2 arom. C); 83.0 (d,
MeOCH); 79.7 (t, OCHCH2); 64.6 (t, SiCH2); 57.2 (q,
MeO); 37.0 (t); 32.2 (d, MeCH); 29.7, 22.8 (2t); 20.5 (q,
arom. H); 5.87 (dq, J¼8.8, 1.7 Hz, CHCSi); 4.33 (dd,
J¼7.4, 4.2 Hz, PhCHOMe); 3.85 (dq, J¼8.8, 7.0 Hz,
PhCHMe); 3.63, 3.43 (AB of ABX, JAB¼10.5 Hz,
JAX¼7.4 Hz, JBX¼4.2 Hz, PhCHCH2O); 3.30 (s, MeO);
3.27, 3.20 (AB, J¼12.9 Hz, SiCH2O); 1.73 (d, J¼1.7 Hz,
MeCSi); 1.31 (d, J¼7.0 Hz, MeCHPh); 0.09, 0.08 (2s,
3
Me2Si). J (1H, 29Si)¼8.1 Hz. 13C NMR of 10b: 146.5 (s,
SiC); 145.3 (d, SiCCH); 139.7, 132.7 (2s, 2 arom. C); 128.4,
128.2 (2d, 2£2 arom. C); 127.7 (d, arom. C); 127.0, 126.9
(2d, 2£2 arom. C); 125.8 (d, arom. C); 82.9 (d, MeOCH);
79.7 (t, OCHCH2); 64.5 (t, SiCH2); 57.2 (q, MeO); 37.9 (d,
MeCH); 21.9 (q, CHMe); 14.9 (q, CMe); 25.1 (q, Me2Si).
1H NMR of the signal of 11b which was shifted from the
signals of 10b: 6.10 (dq, J¼10.3, 1.6 Hz, CHCSi). EI-MS:
368 (,2, Mþz), 135 (48), 121 (100), 117 (26), 105 (70), 91
(30), 89 (46), 77 (28), 75 (33), 73 (39), 59 (41). Anal. calcd
for C23H32O2Si (368.58): C 74.95, H 8.75, found C 74.89, H
8.65.
1
CHMe); 14.8, 14.1 (2q); 25.0, 25.1 (q, Me2Si). H NMR
signal of 11a, which was shifted from the signals of 10a:
5.75 (dq, J¼11.2, 1.6 Hz, CHCSi). 3J (1H, 29Si)¼13.1.
EI-MS: 348 (22, Mþz), 223 (13), 135 (38), 121 (100), 89
(44), 73 (28), 59 (21). Anal. calcd for C21H36O2Si
(348.59): C 72.35, H 10.41, found C 72.60, H 10.59.
4.4. Oxidation of vinylsilanes with NaIO4 in the presence
of RuCl3
4.3.3. {[(2S)-2-Methoxy-2-phenylethoxy]methyl}(di-
methyl)[(E,3R)-1-methyl-3-phenylbut-1-enyl]silane (8b)
and {[(2S)-2-methoxy-2-phenylethoxy]methyl}(di-
methyl)[(Z,3S)-1-methyl-3-phenylbut-1-enyl]silane (9b).
Analogously to Section 4.3.1 Ph2CuLi, obtained from CuI
(1.30 mg, 6.84 mmol) and PhLi (1.8 M soln. in Et2O,
7.60 ml, 13.68 mmol) in Et2O (19 ml), reacted with 5 to
deliver after chromatography (hexane/Et2O 20:1) mixture of
8b and 9b (116 mg, 0.315 mmol, ratio 92:8, 69%) as a
yellow oil. Following data from mixture. [a]D¼þ2.4^0.2
(c¼1.25, CHCl3). IR: 3084w, 3062w, 3028m, 2961s,
2927m, 2894m, 2823m, 1602w, 1493m, 1453m, 1247m,
4.4.1. (S)-(1)-2-Methylhexanoic acid (12). To a stirred
biphasic mixture of CCl4 (0.7 ml), MeCN (0.7 ml), and H2O
(1.0 ml), 8a and 9a (0.114 mg, 0.337 mmol, ratio 98:2),
NaIO4 (0.293 mg, 1.37 mmol), and RuCl3·H2O (4.0 mg,
2.2 mol %) were added. It was stirred vigorously for 2 h at
238C. Then CH2Cl2 (2 ml) was added and the phases were
separated. The aq. phase was extracted with CH2Cl2. The
solvent was removed i.v. and the residue chromatographed
(hexane/Et2O 3:1) to deliver 12 (38 mg, 0.29 mmol, 89%) as
a colorless liquid. The 1H NMR spectrum of the product was
in agreement with the literature data.15 [a]D¼þ15.2^0.2
(c¼0.56, Et2O) (lit: [a]D¼þ20 (c¼6.36, Et2O)15, þ19.7
(c¼6, Et2O).16)
1
1120s, 1101s, 838s, 812m, 758m, 699s. H NMR of 8b:
7.37–7.14 (m, 10 arom. H); 5.87 (dq, J¼8.8, 1.7 Hz,
CHCSi); 4.33 (dd, J¼7.4, 4.2 Hz, PhCHOMe); 3.85 (dq,
J¼8.8, 7.0 Hz, PhCHMe); 3.63, 3.43 (AB of ABX,
JAB¼10.5 Hz, JAX¼7.4 Hz, JBX¼4.2 Hz, PhCHCH2O); 3.30
(s, MeO); 3.27, 3.20 (AB, J¼12.9 Hz, SiCH2O); 1.73 (d,
J¼1.7 Hz, MeCSi); 1.31 (d, J¼7.0 Hz, MeCHPh); 0.09, 0.08
(2s, Me2Si). 3J (1H, 29Si)¼8.0 Hz. 13C NMR of 8b: 146.5 (s,
SiC); 145.3 (d, SiCCH); 139.7, 132.7 (2s, 2 arom. C); 128.4,
128.2 (2d, 2£2 arom. C); 127.7 (d, arom. C); 127.0, 126.9 (2d,
2£2 arom. C); 125.8 (d, arom. C); 82.9 (d, MeOCH); 79.7 (t,
OCHCH2); 64.5 (t, SiCH2); 57.2 (q, MeO); 37.9 (d, MeCH);
4.4.2. (R)-(2)-2-Methylhexanoic acid (12). After reaction
of 10a and 11a (90 mg, 0.26 mmol, ratio 93:7) according to
the procedure mentioned in Section 4.4.1, acid 12 (31 mg,
0.24 mmol, 92%) was obtained as a colorless liquid. The 1H
NMR spectrum of the product was in agreement with the
literature data.17 [a]D¼212.4^0.2 (c¼0.9, Et2O) (lit:
[a]D¼215.3 (c¼14, Et2O).18)
4.4.3. (S)-(1)-2-Phenylpropanoic acid (13). After reaction
of 8b and 9b (79 mg, 0.21 mmol, ratio 92:8) according to
the procedure mentioned in Section 4.4.1, the acid 13 (29 mg,
1
21.9 (q, CHMe); 14.9 (q, CMe); 25.1 (q, Me2Si). H NMR
1
signal of 9b, which was shifted from the signals of 8b: 5.87
(dq, J¼15.6, 1.9 Hz, CHCSi). CI-MS: 386 (100, [MþNH4]þ),
223 (86), 120 (97). Anal. calcd for C23H32O2Si (368.58): C
74.95, H 8.75, found C 74.92, H 8.70.
0.19 mmol, 90%) was obtained as a colorless liquid. The H
NMR spectrum of the product was in agreement with the
literature data.19 [a]D¼þ62.5^0.2 (c¼1.0, CHCl3) (lit:
[a]D¼þ69.2 (c¼1.4, CHCl3),20 þ72.5 (c¼1.0, CHCl3),21
þ70.4 (c¼3.02, CHCl3),22 þ72.8 (c¼1, CHCl3).23)
4.3.4. {[(2S)-2-Methoxy-2-phenylethoxy]methyl}-
(dimethyl)[(E,3S)-1-methyl-3-phenylbut-1-enyl]silane
(10b) and {[(2S)-2-methoxy-2-phenylethoxy]methyl}-
(dimethyl)[(Z,3R)-1-methyl-3-phenylbut-1-enyl]silane
(11b). After reaction of 6 (82 mg, 0.26 mmol) according to
the procedure in Section 4.3.3, 10b and 11b (58 mg,
0.16 mmol, ratio 91:9, 67%) were obtained as a yellow oil.
Following data from mixture. [a]D¼þ85.5^0.2 (c¼1.0,
4.4.4. (R)-(2)-2-Phenylpropanoic acid (13). After reaction
of 10b and 11b (58 mg, 0.16 mmol, ratio 91:9) according to
the procedure mentioned in Section 4.4.1, the acid 13 (20 mg,
0.13 mmol, 85%) was obtained as a colorless liquid. The 1H
NMR spectrum of the product was in agreement with the
literature data.24 [a]D¼260.2^0.2 (c¼0.7, CHCl3) (lit:
[a]D¼267.5 (c¼0.4, CHCl3),24 272.2 (c¼1.0, CHCl3).25)