Job/Unit: O30493
/KAP1
Date: 24-06-13 16:24:14
Pages: 7
Diastereoselective Allylic Substitution with a Silicon Nucleophile
2876 (w), 1626 (vw), 1493 (vw), 1454 (w), 1427 (w), 1112 (m), 1063
1.12 (dd, J = 10.4, J = 4.9 Hz, 1 H), 2.10 (s, 3 H), 3.18 (d, J =
(s), 1002 (s), 833 (m), 809 (s), 725 (s), 697 (s) cm–1 1H NMR 4.9 Hz, 1 H), 3.63 (ddd, J = 17.2, J = 2.0, J = 0.8 Hz, 1 H), 3.87
.
(500 MHz, CDCl3): δ = 0.08 (s, 3 H), 0.26 (s, 3 H), 0.37 (q, J =
(dd, J = 10.3, J = 2.0 Hz, 1 H), 4.90 (ddd, J = 17.2, J = 10.3, J =
7.8 Hz, 6 H), 0.78 (t, J = 7.9 Hz, 9 H), 2.15 (dd, J = 10.4, J = 10.3 Hz, 1 H), 6.07–6.17 (m, 2 H), 6.20 (m, 1 H), 6.26–6.29 (m, 2
5.4 Hz, 1 H), 4.68 (ddd, J = 17.2, J = 2.0, J = 0.6 Hz, 1 H), 4.81
(d, J = 5.3 Hz, 1 H), 4.93 (dd, J = 10.4, J = 2.0 Hz, 1 H), 5.98
(ddd, J = 17.2, J = 10.4, J = 10.4 Hz, 1 H), 7.15–7.25 (m, 5 H),
7.32–7.37 (m, 3 H), 7.44–7.49 (m, 2 H) ppm. 13C NMR (126 MHz,
CDCl3): δ = –3.5, –3.4, 5.2, 6.9, 46.2, 75.9, 114.8, 127.0, 127.3,
127.7, 127.8, 129.0, 134.3, 136.2, 138.2, 145.3 ppm. 29Si NMR
(100 MHz, CDCl3): δ = –4.1, 18.2 ppm. HRMS (APCI): calcd. for
C24H37OSi2 [M + H]+ 397.2368; found 397.2377.
H), 6.35–6.40 (m, 3 H), 6.45–6.56 (m, 2 H) ppm. 13C NMR
(101 MHz, CDCl3): δ = –3.7, –3.7, 44.7, 56.7, 83.9, 114.7, 127.1,
127.3, 127.7, 128.1, 129.1, 134.3, 135.6, 138.1, 141.8 ppm. 29Si
NMR (100 MHz, CDCl3): δ = –3.1 ppm. HRMS (APCI): calcd.
for C19H25OSi [M + H]+ 297.1668; found 297.1669.
tert-Butyl({3-[dimethyl(phenyl)silyl]-1-phenylpent-4-en-2-yl}oxy)di-
methylsilane (anti-γ-6b and syn-γ-6b): (Table 3, Entry 2). Prepared
from (E)-tert-butyl[(5-chloro-1-phenylpent-3-en-2-yl)oxy]dimeth-
ylsilane (2b; 280 mg, 0.880 mmol, 1.00 equiv.) according to GP1 at
–78 °C for 10 h by using CuCN (8.0 mg, 0.088 mmol, 10 mol-%),
NaOMe (95.0 mg, 1.76 mmol, 2.00 equiv.), and Me2PhSiBpin (1,
461 mg, 1.76 mmol, 2.00 equiv.) in THF (10 mL). The crude dia-
stereomeric mixture (dr = 85:15) was purified by flash column
chromatography on silica gel using cyclohexane as eluent to afford
analytically pure anti-γ-6b (299 mg, 81%, γ/α Ͼ 99:1) and syn-γ-6b
(57 mg, 15%, γ/α Ͼ 99:1) as colorless oils.
tert-Butyl({2-[dimethyl(phenyl)silyl]-1-phenylbut-3-en-1yl}oxy)di-
phenylsilane (anti-γ-8a and syn-γ-8a): (Table 2, Entry 3). Prepared
from (E)-tert-butyl[(4-chloro-1-phenylbut-2-en-1-yl)oxy]diphenylsi-
lane (4a; 90 mg, 0.22 mmol, 1.0 equiv.) according to GP1 at –78 °C
for 10 h by using CuCN (2.0 mg, 0.022 mmol 10 mol-%), NaOMe
(24 mg, 0.44 mmol, 2.0 equiv.), and Me2PhSiBpin (1; 116 mg,
0.440 mmol, 2.00 equiv.) in THF (4 mL). Purification by flash col-
umn chromatography on silica gel using cyclohexane as eluent af-
forded a diastereomeric mixture of anti- and syn-γ-8a (60 mg, 54%,
γ/α Ͼ 99:1, dr = 77:33) as a colorless oil. Highly diastereomerically
enriched samples were obtained by repeated flash column
chromatography on silica gel using cyclohexane as eluent. Rf = 0.28
(anti-γ-8a), 0.25 (syn-γ-8a) (cyclohexane). GLC: tR = 30.4 min
anti-γ-6b (major diastereomer): Rf = 0.30 (cyclohexane). GLC: tR
= 21.9 min (anti-γ-6b). IR (ATR): ν = 3070 (vw), 2954 (w), 2929
˜
(w), 2857 (w), 1624 (w), 1472 (w), 1427 (w), 1251 (w), 1065 (w),
1036 (m), 1005 (w), 898 (m), 832 (s), 772 (s), 730 (s), 697 (s) cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.01 (s, 3 H), 0.06 (s, 3 H), 0.32
(s, 3 H), 0.41 (s, 3 H), 0.97 (s, 9 H), 1.97 (dd, J = 10.3, J = 1.8 Hz,
1 H), 2.77–2.95 (m, 2 H), 4.15 (ddd, J = 8.4, J = 5.5, J = 1.9 Hz,
1 H), 4.86 (ddd, J = 17.3, J = 2.2, J = 0.6 Hz, 1 H), 5.16 (dd, J =
10.3, J = 2.2 Hz, 1 H), 6.07 (m, 1 H), 7.14 (m, 2 H), 7.24–7.29 (m,
1 H), 7.32 (m, 2 H), 7.35–7.40 (m, 3 H), 7.43–7.46 (m, 2 H) ppm.
13C NMR (126 MHz, CDCl3): δ = –4.0, –3.7, –3.6, –2.9, 18.4, 26.3,
39.5, 43.5, 74.8, 115.5, 126.2, 127.6, 128.4, 128.9, 129.6, 134.3,
135.8, 138.5, 139.3 ppm. 29Si NMR (100 MHz, CDCl3): δ = –3.2,
16.5 ppm. HRMS (APCI): calcd. for C25H39OSi2 [M + H]+
411.2528; found 411.2534.
(anti-γ-8a), tR = 29.6 min (syn-γ-8a). IR (ATR): ν = 2931 (vw),
˜
2856 (vw), 1463 (w), 1245 (w), 1104 (m), 1013 (m), 996 (m), 731
(m), 687 (s) cm–1. NMR spectroscopic data for anti-γ-8a (major
diastereomer): 1H NMR (400 MHz, CDCl3): δ = –0.25 (s, 3 H),
–0.13 (s, 3 H), 0.98 (s, 9 H), 2.29 (dd, J = 10.8, J = 3.8 Hz, 1 H),
4.85 (d, J = 3.8 Hz, 1 H), 4.89 (dd, J = 2.2, J = 0.4 Hz, 1 H), 5.04
(dd, J = 10.1, J = 2.2 Hz, 1 H), 5.80 (ddd, J = 16.9, J = 10.4, J =
10.4 Hz, 1 H), 7.03 (dd, J = 8.0, J = 1.3 Hz, 2 H), 7.06–7.11 (m, 2
H), 7.17–7.21 (m, 6 H), 7.29–7.43 (m, 7 H), 7.47–7.51 (m, 1 H),
7.73 (dd, J = 8.1, J = 1.4 Hz, 2 H) ppm. 13C NMR (101 MHz,
CDCl3): δ = –5.3, –3.1, 19.6, 27.2, 45.2, 75.3, 116.2, 127.2, 127.5,
127.6, 127.7, 127.7, 127.7, 127.9, 128.8, 129.5, 129.8, 134.0, 134.8,
135.0, 136.0, 136.3, 137.8, 142.6 ppm. NMR spectroscopic data for
syn-γ-6b (minor diastereomer): Rf = 0.19 (cyclohexane). GLC: tR
1
= 22.0 min (syn-γ-6b). H NMR (500 MHz, CDCl3): δ = –0.49 (s,
1
3 H), –0.17 (s, 3 H), 0.39 (s, 3 H), 0.45 (s, 3 H), 0.77 (s, 9 H), 2.19
(dd, J = 10.3, J = 2.9 Hz, 1 H), 2.57–2.69 (m, 2 H), 3.94 (ddd, J =
9.0, J = 4.1, J = 2.9 Hz, 1 H), 4.87 (dd, J = 16.9, J = 1.4 Hz, 1 H),
5.03 (dd, J = 10.1, J = 1.8 Hz, 1 H), 5.96 (ddd, J = 16.3, J = 10.3,
J = 10.3 Hz, 1 H), 6.93 (m, 2 H), 7.13 (m, 1 H), 7.19 (m, 2 H),
7.38–7.45 (m, 3 H), 7.54–7.65 (m, 2 H) ppm. 13C NMR (126 MHz,
CDCl3): δ = –5.3, –4.5, –3.3, –3.1, 18.2, 26.1, 42.0, 44.0, 75.6, 115.3,
126.0, 128.0, 128.2, 129.3, 129.7, 134.3, 135.8, 138.1, 140.3 ppm.
HRMS (APCI): calcd. for C25H39OSi2 [M + H]+ 411.2528; found
411.2534.
syn-γ-8a (minor diastereomer): H NMR (400 MHz, CDCl3): δ =
–0.30 (s, 3 H), –0.05 (s, 3 H), 0.91 (s, 9 H), 2.44 (dd, J = 10.5, J =
9.1 Hz, 1 H), 4.64 (d, J = 9.0 Hz, 1 H), 4.77 (ddd, J = 16.9, J =
1.9, J = 0.6 Hz, 1 H), 4.88 (dd, J = 10.2, J = 1.9 Hz, 1 H), 5.51
(ddd, J = 16.9, J = 10.4, J = 10.4 Hz, 1 H), 6.97 (dd, J = 8.0, J =
1.4 Hz, 2 H), 7.06–7.15 (m, 7 H), 7.16–7.24 (m, 5 H), 7.28–7.32 (m,
2 H), 7.35–7.43 (m, 2 H), 7.59 (dd, J = 8.0, J = 1.3 Hz, 2 H) ppm.
13C NMR (101 MHz, CDCl3): δ = –4.0, –2.5, 19.5, 27.2, 31.1, 46.3,
115.0, 127.1, 127.3, 127.5, 127.6, 127.7, 127.9, 128.7, 129.2, 129.5,
134.1, 134.1, 134.5, 135.0, 136.3, 136.5, 138.0, 143.9 ppm. HRMS
(APCI): calcd. for C34H41OSi2 [M + H]+ 521.2690; found 521.2690.
anti-({3-[Dimethyl(phenyl)silyl]-1-phenylpent-4-en-2-yl}oxy)triethyl-
anti-(1-Methoxy-1-phenylbut-3-en-2-yl)dimethyl(phenyl)silane (anti- silane (anti-γ-7b): (Table 3, Entry 5). Prepared from (E)-[(5-chloro-
γ-9a): (Table 2, Entry 4 and Table 3, Entry 7). Prepared from (E)-
(4-chloro-1-methoxybut-2-en-1-yl)benzene (5a; 69 mg, 0.33 mmol,
1.0 equiv.) according to GP1 at –78 °C for 10 h by using CuCN
1-phenylpent-3-en-2-yl)oxy]triethylsilane (3b; 69 mg, 0.22 mmol,
1.0 equiv.) according to GP1 at –78 °C for 10 h by using CuCN
(2.0 mg, 0.022 mmol, 10 mol-%), NaOMe (24 mg, 0.44 mmol,
(3.0 mg, 0.033 mmol, 10 mol-%), NaOMe (36 mg, 0.66 mmol, 2.0 equiv.), and Me2PhSiBpin (1; 116 mg, 0.440 mmol, 2.00 equiv.)
2.0 equiv.), and Me2PhSiBpin (1; 173 mg, 0.660 mmol, 2.00 equiv.)
in THF (5 mL). Purification by flash column chromatography on
silica gel (cyclohexane/ethyl acetate = 97:3) afforded analytically
pure anti-γ-9a (101 mg, 97%, γ/α Ͼ 99:1, dr = 96:4) as a colorless
solid. M.p. = 59–62 °C. Rf = 0.26 (cyclohexane/ethyl acetate =
in THF (4 mL). Purification by flash column chromatography on
silica gel using cyclohexane as eluent afforded analytically pure
anti-γ-7b (73 mg, 81%, γ/α Ͼ 99:1, dr = 88:12) as a colorless oil. Rf
= 0.32 (cyclohexane). GLC: tR = 22.6 min (anti-γ-7b). IR (ATR): ν
˜
= 3249 (vw), 2954 (w), 2876 (w), 1624 (vw), 1497 (vw), 1454 (w),
1427 (w), 1245 (m), 1096 (s), 1064 (s), 1064 (s), 1040 (s), 1005 (s),
97:3). GLC: tR = 17.9 min (anti-γ-9a). IR (ATR): ν = 2925 (m),
˜
2854 (w), 1729 (vw), 1625 (vw), 1453 (vw), 1427 (m), 1308 (m), 810 (s), 729 (s), 696 (s) cm–1. 1H NMR (500 MHz, CDCl3): δ =
1247 (m), 1112 (s), 835 (s), 1813 (s), 788 (m), 727 (s), 698 (s) cm–1. 0.24 (s, 3 H), 0.35 (s, 3 H), 0.57 (q, J = 8.0 Hz, 6 H), 0.95 (t, J =
1H NMR (400 MHz, CDCl3): δ = –0.82 (s, 3 H), –0.68 (s, 3 H),
7.9 Hz, 9 H), 1.87 (dd, J = 10.4, J = 1.5 Hz, 1 H), 2.80 (dd, J =
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