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ethyl acetate−hexanes; UV, CAM). H NMR (500 MHz, CDCl3) δ
tetrahydrofuran (1.0 mL) at 24 °C. Tributyltin hydride (88.6 μL,
334 μmol, 4.00 equiv) was added dropwise via syringe pump over 1 h
at 24 °C. Upon completion of the addition, the product mixture was
concentrated to dryness. The residue obtained was purified by flash
column chromatography (eluting with 30% ethyl acetate−hexanes) to
afford the vinylstannane 126 as a clear oil (25.0 mg, 51%): Rf = 0.35
(30% ethyl acetate−hexanes; UV, CAM); 1H NMR (400 MHz,
CDCl3) δ 6.34 (d, 1H, J = 18.8 Hz) 6.19−6.17 (m, 1H), 5.99−5.97
(m, 1H), 5.80 (d, 1H, J = 18.8 Hz) 3.97 (s, 3H), 3.59 (s, 3H), 3.29 (br
s, 1H), 2.95 (app t, 1H, J = 7.2 Hz), 2.73−2.64 (m, 3H), 2.27 (s, 3H),
2.02−1.94 (m, 1H), 1.62−1.50 (m, 8H), 1.42−1.25 (m, 7H), 0.94−
0.88 (m, 15H); 13C NMR (100 MHz, CDCl3) δ 196.3 (C), 165.5 (C),
147.5 (CH), 140.0 (C), 136.4 (CH), 136.2 (CH), 126.7 (CH), 73.0
(C), 60.7 (CH3), 60.2 (CH3), 58.8 (CH), 54.2 (CH), 53.0 (C), 52.5
(CH), 50.4 (CH2), 47.6 (CH2), 39.6 (CH2), 35.4 (CH3), 29.4 (3 ×
CH2), 27.4 (3 × CH2), 13.9 (3 × CH3), 9.8 (3 × CH2); IR (ATR-
FTIR), cm−1 2920 (br), 1718 (s), 1655 (s), 1602 (s), 1280 (s);
HRMS-CI (m/z) [M + H]+ calcd for C30H50NO3Sn 592.2813, found
592.2817.
6.10−6.09 (m, 1H), 5.88−5.87 (m, 1H), 5.74 (dd, 1H, J = 17.0, 10.5
Hz), 5.51 (dd, 1H, J = 17.0, 2.5 Hz), 5.26 (dd, 1H, J = 10.5, 2.5 Hz),
3.98 (s, 3H), 3.59 (s, 3H), 3.35 (br s, 1H), 2.93 (app t, 1H, J = 7.0
Hz), 2.71 (br s, 1H), 2.67−2.61 (m, 2H), 2.28 (s, 3H), 2.07−2.01 (m,
1H), 1.65−1.62 (m, 1H), 1.26 (s, 1H), 0.10 (s, 9H); 13C NMR (125
MHz, CDCl3) δ 196.1 (C), 164.7 (C), 139.9 (C), 139.2 (CH), 136.0
(CH), 135.8 (CH), 115.1 (CH2), 71.4 (C), 61.4 (CH3), 60.9 (CH3),
60.1 (C), 55.9 (CH), 55.3 (CH), 53.6 (CH), 52.3 (CH2), 49.5 (CH),
39.6 (CH2), 35.4 (CH3), −0.1 (TMS); IR (ATR-FTIR), cm−1 2950
(br), 1650 (s), 1602 (s), 1245 (s), 1215 (s); HRMS-CI (m/z) [M +
H]+ calcd for C21H32NO3Si, 374.2151, found 374.2169; [α]20D +106 (c
1.0, CHCl3).
Synthesis of the Vinylsilane 124. Platinum oxide (30.0 mg, 134
μmol, 1.60 equiv) was added portionwise to a solution of the acetylide
addition product 33 (25.0 mg, 83.6 μmol, 1 equiv) in dimethylphenyl
silane (1.9 mL) in a 10-mL round-bottomed flask that had been fused
to a Teflon-coated valve at 24 °C. The vessel was sealed, and the
sealed reaction vessel was stirred and heated for 4 h at 60 °C. The
product mixture was allowed to cool over 20 min to 24 °C. The cooled
product mixture was diluted with ethyl acetate (5 mL), and the diluted
solution was filtered through a pad of Celite. The filtrate was
concentrated, and the residue obtained was purified by flash column
chromatography (eluting with 30% ethyl acetate−hexanes) to afford
the vinylsilane 124 as a clear oil (20.0 mg, 55%): Rf = 0.60 (50% ethyl
Synthesis of the Vinylstannane 127. Tetrakis(triphenyl-
phosphine)palladium (62.8 mg, 54.4 μmol, 0.20 equiv) was added to
a solution of the terminal alkyne 68 (90.0 mg, 272 μmol, 1 equiv) in
tetrahydrofuran (2.7 mL) at 24 °C. Tributyltin hydride (144 μL, 544
μmol, 2.00 equiv) was added dropwise via syringe pump over 1 h at 24
°C. Upon completion of the addition, the product mixture was
concentrated to dryness. The residue obtained was purified by flash
column chromatography (eluting with 20% ethyl acetate−hexanes) to
afford the vinylstannane 127 as a clear oil (140 mg, 78%): Rf = 0.45
(30% ethyl acetate−hexanes; UV, CAM); 1H NMR (400 MHz,
CDCl3) δ 6.35 (d, 1H, J = 18.8 Hz) 6.07−6.06 (m, 1H), 5.87−5.85
(m, 1H), 5.79 (d, 1H, J = 18.8 Hz) 3.94 (s, 3H), 3.57 (s, 3H), 3.34 (br
s, 1H), 2.92 (app t, 1H, J = 7.2 Hz), 2.68−2.64 (m, 3H), 2.25 (s, 3H),
2.02−1.94 (m, 1H), 1.56−1.51 (m, 7H), 1.35−1.30 (m, 6H), 1.24 (s,
1H), 0.94−0.87 (m, 15H), −0.12 (s, 9H); 13C NMR (100 MHz,
CDCl3) δ 196.2 (C), 165.4 (C), 147.7 (CH), 140.0 (C), 136.1 (CH),
135.6 (CH), 126.6 (CH), 73.0 (C), 61.2 (CH3), 60.7 (CH3), 60.1
(CH), 55.9 (C, CH), 53.5 (CH), 52.3 (CH2), 49.4 (CH), 39.9 (CH2),
35.4 (CH3), 29.3 (3 × CH2), 27.3 (3 × CH2), 13.9 (3 × CH3), 9.8 (3
× CH2), −0.1 (TMS); IR (ATR-FTIR), cm−1 2915 (br), 1650 (m),
1605 (m), 1250 (m), 1215 (m); HRMS-CI (m/z) [M + H]+ calcd for
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acetate−hexanes; UV, CAM); H NMR (500 MHz, CDCl3) δ 7.57−
7.55 (m, 2H), 7.37−7.35 (m, 3H), 6.21 (d, 1H, J = 18.5 Hz), 6.17 (d,
1H, J = 18.5 Hz), 4.04 (s, 3H), 3.72 (s, 3H), 2.91 (t, 1H, J = 8.0 Hz),
2.75 (br s, 1H), 2.67−2.62 (m, 1H), 2.33 (s, 3H), 2.29 (d, 1H, J = 5.0
Hz), 2.03 (br d, 1H, J = 3.5 Hz), 1.81−1.75 (m, 1H), 1.61 (br s, 1H),
1.51−1.35 (m, 3H), 1.31−1.28 (m, 2H), 1.23−1.21 (m, 1H), 0.37 (s,
3H), 0.36 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 197.6 (C), 164.6
(C), 149.1 (CH), 139.6 (C), 138.5 (C), 134.0 (2 × CH), 129.0 (CH),
127.8 (2 × CH), 127.0 (CH), 71.8 (C), 61.2 (CH3), 60.6 (CH3), 56.4
(CH), 55.4 (C), 51.2 (CH2), 46.3 (CH), 43.8 (CH), 38.6 (CH2), 37.6
(CH2), 35.4 (CH3), 25.7 (CH2), 23.7 (CH2), −1.8 (CH3), −2.0
(CH3); IR (ATR-FTIR), cm−1 2958 (br), 1656 (s), 1600 (s), 1250
(s); HRMS-CI (m/z) [M + H]+ calcd for C26H36NO3Si 438.2464,
found 438.2479.
Synthesis of the Vinylsilane 125. Platinum oxide (25.0 mg, 110
μmol, 1.60 equiv) was added portionwise to a solution of the terminal
alkyne 68 (25.0 mg, 67.4 μmol, 1 equiv) in dimethylphenylsilane (1.5
mL) in a 10-mL round-bottomed flask that had been fused to a
Teflon-coated valve at 24 °C. The vessel was sealed, and the sealed
reaction vessel was placed in an oil bath that had been preheated to 60
°C. The reaction mixture was stirred and heated for 2 h at 60 °C. The
product mixture was allowed to cool over 20 min to 24 °C. The cooled
product mixture was diluted with ethyl acetate (5 mL), and the diluted
solution was filtered through a pad of Celite. The filtrate was
concentrated, and the residue obtained was purified by flash column
chromatography (eluting with 30% acetone−hexanes) to afford the
vinylsilane 125 as a clear oil (26.0 mg, 76%): Rf = 0.70 (30% acetone−
C33H58NO3SiSn 664.3208, found 664.3207; [α]20 +115 (c 2.0,
D
CHCl3).
Synthesis of the β-Silylethyl Derivative 128. Platinum oxide
(27.4 mg, 121 μmol, 1.80 equiv) was added portionwise to a solution
of the terminal alkene 123 (25.0 mg, 67.0 μmol, 1 equiv) in
dimethylphenylsilane (1.5 mL) in a 10-mL round-bottomed flask that
had been fused to a Teflon-coated valve at 24 °C. The vessel was
sealed, and the sealed reaction vessel was placed in an oil bath that had
been preheated to 60 °C. The reaction mixture was stirred and heated
for 2 h at 60 °C. The product mixture was allowed to cool over 20 min
to 24 °C. The cooled product mixture was diluted with ethyl acetate (5
mL), and the diluted solution was filtered through a pad of Celite. The
filtrate was concentrated, and the residue obtained was purified by
flash column chromatography (eluting with 25% ethyl acetate−
hexanes) to afford the β-silylethyl derivative 128 as a clear oil (19.0
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hexanes; UV, CAM); H NMR (500 MHz, CDCl3) δ 7.59−7.57 (m,
2H), 7.37−7.36 (m, 3H), 6.29 (d, 1H, J = 18.5 Hz), 5.94−5.90 (m,
2H), 5.84−5.83 (m, 1H), 3.93 (s, 3H), 3.58 (s, 3H), 3.34 (br s, 1H),
2.95 (dd, 1H, J = 9.0, 6.0 Hz), 2.66−2.61 (m, 2H), 2.59 (br s, 1H),
2.27 (s, 3H), 2.00−1.95 (m, 1H), 1.62−1.58 (m, 1H), 1.23 (s, 1H),
0.40 (s, 3H), 0.39 (s, 3H), −0.11 (s, 9H); 13C NMR (125 MHz,
CDCl3) δ 196.1 (C), 164.7 (C), 149.5 (CH), 140.2 (C), 139.5 (C),
136.2 (CH), 135.6 (CH), 134.0 (2 × CH), 129.0 (CH), 127.9 (2 ×
CH), 126.2 (CH), 72.5 (C), 61.3 (CH), 60.8 (CH3), 60.2 (CH3), 56.2
(CH), 55.7 (C), 53.4 (CH), 52.5 (CH2), 49.4 (CH), 40.0 (CH2), 35.5
(CH3), −0.3 (TMS), −1.9 (CH3), −2.0 (CH3); IR (ATR-FTIR),
cm−1 2955 (br), 1648 (m), 1602 (m), 1250 (s), 1215 (m); HRMS-CI
(m/z) [M + H]+ calcd for C29H42NO3Si2 508.2703, found 508.2705;
[α]20 +148 (c 1.0, CHCl3).
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mg, 56%): Rf = 0.60 (60% ethyl acetate−hexanes; UV, CAM); H
NMR (400 MHz, CDCl3) δ 7.57−7.55 (m, 2H), 7.38−7.36 (m, 3H),
5.91−5.89 (m, 1H), 5.80−5.78 (m, 1H), 3.85 (s, 3H), 3.57 (s, 3H),
3.28 (br s, 1H), 2.86−2.82 (m, 2H), 2.71−2.70 (app d, 1H, J = 4.0
Hz), 2.51−2.44 (m, 1H), 2.26 (s, 3H), 2.13−2.06 (m, 1H), 1.72−1.65
(m, 2H), 1.44−1.36 (m, 1H), 1.26 (s, 1H), 1.10−0.98 (m, 2H), 0.31
(s, 6H), −0.09 (s, 9H); 13C NMR (100 MHz, CDCl3) δ 196.0 (C),
167.0 (C), 140.3 (C), 139.8 (C), 135.7 (CH), 135.5 (CH), 133.8 (2 ×
CH), 129.0 (CH), 127.9 (2 × CH), 69.9 (C), 63.3 (CH3), 61.0
(CH3), 59.7 (CH), 56.0 (CH), 54.3 (CH), 53.3 (CH2), 52.6 (C), 49.5
(CH), 40.6 (CH2), 37.2 (CH3), 29.2 (CH2), 11.2 (CH2), 0.02 (TMS),
−2.9 (2 × CH3); IR (ATR-FTIR), cm−1 2915 (s), 1730 (s), 1652 (m),
1600 (m), 1460 (m); HRMS-CI (m/z) [M + H]+ calcd for
SyDnthesis of the Vinylstannane 126. Tetrakis(triphenyl-
phosphine)palladium (24.1 mg, 20.9 μmol, 0.25 equiv) was added to
a solution of the terminal alkyne 33 [25.0 mg, 83.6 μmol, 1 equiv;
dried by azeotropic distillation with benzene (3.0 mL)] in
C29H44NO3Si2 510.2860, found 510.2830; [α]20 +85 (c 0.2, CHCl3).
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dx.doi.org/10.1021/jo401889b | J. Org. Chem. XXXX, XXX, XXX−XXX