Stereoselective synthesis of (e)-α-selenenylvinylsilanes via the hydromagnesiation reaction of alkynylsilanes

Article abstract of DOI:10.1055/s-2002-33123

(E)-α-Selenenylvinylsilanes have been synthesized stereoselectively via the hydromagnesiation of alkynylsilanes, followed by the reaction with arylselenenyl bromides. (E)-α-Selenenylvinylsilanes can undergo the desilylation reaction in the presence of a c

Full text of DOI:10.1055/s-2002-33123

PAPER
1347
Stereoselective Synthesis of (E)- -Selenenylvinylsilanes via the
Hydromagnesiation Reaction of Alkynylsilanes
S
H
ynthesis of
(
E
)-
-
o
Selenenylvin
n
ylsilanes g Zhao, Mingzhong Cai*
Department of Chemistry, Jiangxi Normal University, Nanchang 330027, P. R. China
Fax +86(791)8511619; E-mail: Caimz@fm365.com
Received 5 March 2002; revised 16 April 2002
1
Investigations of the crude products 4 by H NMR spec-
troscopy (300 MHz) showed their isomeric purities to be
more than 96%. One olefinic proton signal of 4 splits
Abstract: (E)- -Selenenylvinylsilanes have been synthesized ste-
reoselectively via the hydromagnesiation of alkynylsilanes, fol-
lowed by the reaction with arylselenenyl bromides. (E)- -
Selenenylvinylsilanes can undergo the desilylation reaction in the characteristically into one triplet with a coupling constant
presence of a catalytic amount of hydriodic acid to give (E)-vinyl J = 7.0 Hz, which indicated that the hydromagnesiation to
selenides in high yields.
the alkynylsilanes had taken place with strong preference
Key words: hydromagnesiation, (E)- -selenenylvinylsilane, alky- for the addition of the magnesium atom at the carbon ad-
nylsilane, stereoselectivity, (E)-vinyl selenide
jacent to the silyl group. The other results of the reaction
are summarized in Table 1.
Table 1 Synthesis of (E)- -Selenenylvinylsilanes
Bifunctional-group reagents, which have two different
functional groups linked to the olefinic carbon atoms, for
example, Sn–Si, Si–Zr, Se–B, Se–Sn, and Se–Zr combi-
nations, play an important role in organic synthesis, espe-
cially in developing many convenient methods for the
stereoselective preparation of substituted alkenes. These
reagents and their synthetic applications have been report-
Producta
b
Entry
R
Ar
Ph
Yield (%)
a
b
c
d
e
f
n-C H
4a
4b
4c
4d
4e
4f
81
84
78
80
85
79
82
86
80
72
76
68
4
9
9
n-C H
4-ClC H
4
6
4
n-C
H
4-MeC
Ph
H
6
4
9
4
4
4
4
1
ed. Both vinylsilanes and vinyl selenides are important
i-C H
5
11
11
11
intermediates, but the bifunctional-group reagent contain-
ing selenium and silicon has rarely aroused attention. Re-
i-C H
4-ClC H
6 4
5
2
cently, Xu et al. described that alkynylsilanes underwent
i-C H
4-MeC H
5
6
hydrozirconation and the successive reaction with selene-
nyl bromides to give (E)- -selenenylvinylsilanes. Hydro-
magnesiation has emerged as a unique hydrometalation
with some attractive features, such as the high regioselec-
tivity and stereoselectivity observed with alkynylsi-
g
h
i
n-C H
Ph
4g
4h
4i
6
13
13
13
n-C H
4-ClC H
4
6
6
n-C H
4-MeC H
6
6
3
,4
lanes.
We now wish to report that (E)- -
j
PhCH2
PhCH2
PhCH2
Ph
4j
selenenylvinylsilanes could be synthesized by hydromag-
nesiation of alkynylsilanes, followed by treatment with
selenenyl bromides.
k
4-ClC H
4k
6
4
l
4-MeC H
4l
6
Alkynylsilanes 1 were prepared according to the literature
5
a
1
procedure. Hydromagnesiation of alkynylsilanes at 25 °C
All the compounds were characterized using H NMR, IR, and MS
or elemental analyses.
in diethyl ether for 6 hours gave (Z)- -silylvinyl Grignard
reagents 2, which reacted with selenenyl bromides 3 in
THF to afford (E)- -selenenylvinylsilanes 4. The yields
were 68–86% (Scheme 1).
b
Isolated yield based on the alkynylsilane used.
Scheme 1
Synthesis 2002, No. 10, 30 07 2002. Article Identifier:
1
©
437-210X,E;2002,0,10,1347,1350,ftx,en;F02102SS.pdf.
Georg Thieme Verlag Stuttgart · New York
ISSN 0039-7881

1
348
H. Zhao, M. Cai
PAPER
Vinyl selenides are promising synthetic intermediates ow- were measured using a Yanaco MT-3 CHN microelemental analy-
ser. All solvents were dried, deoxygenated and freshly distilled be-
fore use.
ing to the versatile reactivity of the selenenyl group and
the carbon–carbon double bond, but only a few methods
6
for the synthesis of (E)-vinyl selenides are available. The
(
E)- -Selenenylvinylsilanes 4a–l; General Procedure
reaction of selenoacetylenes with LiAlH gave (E)-vinyl
4
To a solution of isobutylmagnesium bromide (4.5 mmol) in Et O (7
mL) was added Cp TiCl (50 mg, 0.2 mmol) at 0 °C under Ar, and
2
7
selenides. Hydroboration of 1-alkynes afforded (E)-alke-
2
2
nylboronic acids, which were treated with NaOH fol- the mixture was stirred for 30 min at that temperature. To this solu-
lowed by PhSeBr to give stereoselectively (E)-vinyl tion was added alkynylsilane 1 (4.0 mmol), and the mixture was
8
stirred for 6 h at 25 °C. After removal of the Et O under reduced
selenides. Hydrozirconation of arylselenoethynes gave
2
pressure (2 h, r.t./2 Torr), the residue was dissolved in THF (6 mL),
cooled to –10 °C, and a solution of ArSeBr (4.0 mmol) in THF (6
mL) was added dropwise over 30 min with stirring. The reaction
mixture was brought to 30 °C gradually and stirred for 8 h,
selenium-containing alkenylzirconium(IV) complexes,
which were cross-coupled with aryl halides in the pres-
ence of Pd(PPh ) to afford (E)-vinyl selenides. We car-
ried out the desilylation reaction of (E)- - quenched with sat. aq NH Cl (25 mL) and extracted with Et O
9
3
4
4
2
selenenylvinylsilanes 4 in the presence of a catalytic (2 30 mL). The organic layer was washed with sat. aq NH Cl (20
4
mL) and H O (3 30 mL) and dried (MgSO ). Removal of solvent
amount of 57% hydriodic acid at room temperature in
benzene for an hour to give (E)-vinyl selenides 5 with
high stereoselectivity and in high yields (Scheme 2). The
experimental results are summarized in Table 2.
2
4
under reduced pressure gave an oil, which was purified by column
chromatography on silica gel using light petroleum (bp 30–60 °C)
as eluent.
4
a
IR (film): 3070, 3017, 2960, 2925, 2860, 1585, 1488, 1247, 840,
–
1
7
40 cm .
1H NMR (CDCl3): = 7.43–7.35 (m, 2 H), 7.32–7.14 (m, 3 H), 6.63
t, J = 7.0 Hz, 1 H), 2.31–2.17 (m, 2 H), 1.45–1.25 (m, 4 H), 0.91 (t,
(
Scheme 2
J = 5.4 Hz, 3 H), 0.15 (s, 9 H).
MS: m/z = 312 (M+).
Table 2 Synthesis of (E)-Vinyl Selenides
Anal. Calcd for C H SiSe: C, 57.88; H, 7.72. Found: C, 57.61; H,
1
5
24
7
.58.
b
Entry
R
Ar
Ph
Producta
5a
Yield (%)
4
b
a
b
c
n-C H9
80
82
79
74
81
83
4
IR (film): 3070, 3016, 2962, 2930, 2865, 1590, 1495, 1249, 839,
735 cm .
1H NMR (CDCl3): = 7.40–7.01 (m, 4 H), 6.55 (t, J = 7.0 Hz, 1 H),
2
0
–
1
n-C H9
4-ClC H
5b
4
6
4
i-C H
Ph
5c
5
11
11
.45–2.05 (m, 2 H), 1.54–1.10 (m, 4 H), 0.92 (t, J = 5.4 Hz, 3 H),
.15 (s, 9 H).
d
e
i-C H
4-MeC H
5d
5
6
4
MS: m/z = 346 (M+).
n-C H
Ph
5e
6
13
13
Anal. Calcd for C H ClSiSe: C, 52.05; H, 6.65. Found: C, 51.89;
H, 6.44.
1
5
23
f
n-C H
4-ClC H
4
5f
6
6
a
1
All the compounds were characterized using H NMR, IR, and ele-
mental analyses.
4
c
IR (film): 3070, 3017, 2956, 2926, 2856, 1589, 1489, 1247, 839,
8
b
Isolated yield based on the (E)- -selenenylvinylsilane used.
–1
00, 753 cm .
1H NMR (CDCl3): = 7.38–6.79 (m, 4 H), 6.41 (t, J = 7.0 Hz, 1 H),
The stereochemistry of products 5 was easily established, 2.50–2.01 (m, 5 H), 1.56–1.12 (m, 4 H), 0.91 (t, J = 5.4 Hz, 3 H),
1
0
.15 (s, 9 H).
since H NMR spectra of products 5a–f show a doublet at
=
6.3–6.5 with a coupling constant of 15 Hz, typical of MS: m/z = 326 (M+).
1
0
trans-positioned hydrogen atoms.
Anal. Calcd for C H SiSe: C, 59.00; H, 7.99. Found: C, 58.79; H,
7.62.
1
6
26
2
In summary, compared to the reported method, the
present method for the synthesis of (E)- -selenenylvinyl-
silanes has the advantages of readily available and cheap
4
d
IR (film): 3070, 2955, 2915, 2870, 1578, 1475, 1384, 1366, 1249,
860, 839, 734, 690 cm .
starting materials instead of the expensive Cp Zr(H)Cl,
–1
2
straightforward and simple procedures, mild reaction con-
ditions and high yields. The investigation on the synthetic
applications of (E)- -selenenylvinylsilanes is in progress.
1H NMR (CDCl3): = 7.39–6.87 (m, 5 H), 6.41 (t, J = 6.9 Hz, 1 H),
2
0
.42–2.01 (m, 2 H), 1.70–1.11 (m, 3 H), 0.88 (d, J = 6.7 Hz, 6 H),
.14 (s, 9 H).
MS: m/z = 326 (M+).
1H NMR spectra were recorded on an AZ-300MHz spectrometer
with TMS as an internal standard. IR spectra were obtained on a
Perkin-Elmer 683 instrument as neat films. Mass spectra were de-
termined on a Finnigan 8230 mass spectrometer. Microanalyses
Anal. Calcd for C H SiSe: C, 59.00; H, 7.99. Found: C, 58.72; H,
1
6
26
7
.59.
Synthesis 2002, No. 10, 1347–1350 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Synthesis of (E)- -Selenenylvinylsilanes
1349
4
e
1H NMR (CDCl3): = 7.55–7.03 (m, 9 H), 6.61 (t, J = 7.0 Hz, 1 H),
3.57 (d, J = 7.3 Hz, 2 H), 0.15 (s, 9 H).
MS: m/z = 380 (M+).
IR (film): 3073, 2954, 2870, 1628, 1578, 1471, 1385, 1366, 1249,
8
1H NMR (CDCl3): = 7.37–6.92 (m, 4 H), 6.46 (t, J = 7.0 Hz, 1 H),
2
0
–1
38, 756 cm .
Anal. Calcd for C H ClSiSe: C, 56.86; H, 5.53. Found: C, 56.54;
1
8
21
.48–2.00 (m, 2 H), 1.72–1.12 (m, 3 H), 0.90 (d, J = 6.7 Hz, 6 H),
.15 (s, 9 H).
H, 5.31.
MS: m/z = 360 (M+).
4l
–
1
IR (film): 3060, 3025, 2955, 2850, 1579, 1495, 1249, 840, 754 cm .
1H NMR (CDCl3): = 7.46–6.92 (m, 9 H), 6.51 (t, J = 7.0 Hz, 1 H),
Anal. Calcd for C H ClSiSe: C, 53.35; H, 6.95. Found: C, 53.10;
16
25
H, 6.72.
3
.54 (d, J = 7.2 Hz, 2 H), 2.28 (s, 3 H), 0.10 (s, 9 H).
4
f
MS: m/z = 360 (M+).
IR (film): 3069, 3016, 2952, 2869, 1631, 1577, 1488, 1384, 1366,
1
1H NMR (CDCl3): = 7.28–6.79 (m, 4 H), 6.38 (t, J = 7.0 Hz, 1 H),
–
1
Anal. Calcd for C H SiSe: C, 63.43; H, 6.68. Found: C, 63.14; H,
249, 860, 839, 800 cm .
19 24
6
.45.
2
0
.45–1.95 (m, 5 H), 1.70–1.10 (m, 3 H), 0.89 (d, J = 6.7 Hz, 6 H),
.15 (s, 9 H).
(
E)-Vinyl Selenides 5a–f; General Procedure
To a solution of (E)- -selenenylvinylsilane 4 (0.5 mmol) in benzene
(1 mL) was added aq 57% HI (0.04 mL). The mixture was stirred at
MS: m/z = 340 (M+).
r.t. for 1 h, quenched with sat. aq NaHCO (10 mL) and extracted
3
Anal. Calcd for C H SiSe: C, 60.10; H, 8.25. Found: C, 60.31; H,
17
28
with Et O (2 15 mL). The ethereal solution was washed with H O
2
2
8
.40.
(
3
20 mL), dried (MgSO ) and concentrated under reduced pres-
4
sure. The oily residue was purified by flash column chromatogra-
phy on silica gel using light petroleum (bp 30–60 °C) as eluent to
give 5a–f as oils.
4
g
–
1
IR (film): 3070, 2960, 2855, 1590, 1485, 1250, 840, 740, 690 cm .
1H NMR (CDCl3): = 7.51–7.07 (m, 5 H), 6.59 (t, J = 6.9 Hz, 1 H),
2
0
.45–2.18 (m, 2 H), 1.60–1.13 (m, 8 H), 0.88 (t, J = 5.3 Hz, 3 H),
.05 (s, 9 H).
5
a
–1
IR (film): 3070, 3017, 2956, 2860, 1588, 1490, 800, 750 cm .
MS: m/z = 340 (M+).
1
H NMR (CDCl ): = 7.62–7.10 (m, 5 H), 6.41 (d, J = 15 Hz, 1 H),
3
5
.96 (dt, J = 15, 6 Hz, 1 H), 2.32–1.91 (m, 2 H), 1.42–1.16 (m, 4
Anal. Calcd for C H SiSe: C, 60.10; H, 8.25. Found: C, 60.36; H,
17
28
H), 1.10–0.72 (m, 3 H).
8
.39.
Anal. Calcd for C H Se: C, 60.25; H, 6.69. Found: C, 60.56; H,
1
2
16
4
h
6
.90.
IR (film): 3069, 3016, 2958, 2860, 1587, 1490, 1248, 839, 756
cm .
1H NMR (CDCl3): = 7.41–7.12 (m, 4 H), 6.68 (t, J = 7.0 Hz, 1 H),
2
0
–
1
5
b
–
1
IR (film): 3070, 3019, 2958, 2862, 1590, 1485, 800, 728 cm .
.44–2.17 (m, 2 H), 1.50–1.17 (m, 8 H), 0.89 (t, J = 5.3 Hz, 3 H),
.15 (s, 9 H).
1
H NMR (CDCl ): = 7.70–7.15 (m, 4 H), 6.50 (d, J = 15 Hz, 1 H),
3
6
.02 (dt, J = 15, 6 Hz, 1 H), 2.38–1.94 (m, 2 H), 1.45–1.18 (m, 4 H),
MS: m/z = 374 (M+).
1.11–0.73 (m, 3 H).
Anal. Calcd for C H ClSe: C, 52.65; H, 5.48. Found: C, 52.91; H,
Anal. Calcd for C H ClSiSe: C, 54.56; H, 7.22. Found: C, 54.27;
H, 7.03.
12 15
17
27
5
.65.
5
c
4
i
–
1
–
1
IR (film): 3070, 3020, 2957, 2858, 1589, 1495, 860, 734, 690 cm .
IR (film): 3070, 2956, 2855, 1589, 1488, 1247, 838, 800, 753 cm .
1H NMR (CDCl3): = 7.31–6.93 (m, 4 H), 6.56 (t, J = 7.0 Hz, 1 H),
2
1
H NMR (CDCl ): = 7.60–7.08 (m, 5 H), 6.40 (d, J = 15 Hz, 1 H),
3
5
0
.94 (dt, J = 15, 6 Hz, 1 H), 2.38–1.96 (m, 2 H), 1.71–1.12 (m, 3 H),
.88 (d, J = 6.7 Hz, 6 H).
.48–2.33 (m, 2 H), 2.29 (s, 3 H), 1.51–1.19 (m, 8 H), 0.91 (t,
J = 5.4 Hz, 3 H), 0.05 (s, 9 H).
MS: m/z = 354 (M+).
Anal. Calcd for C H Se: C, 61.66; H, 7.11. Found: C, 61.89; H,
13 18
7
.37.
Anal. Calcd for C H SiSe: C, 61.11; H, 8.49. Found: C, 61.34; H,
18
30
8
.63.
5
d
–
1
IR (film): 3070, 3018, 2960, 2862, 1590, 1487, 880, 800, 753 cm .
4
j
1
H NMR (CDCl ): = 7.61–7.04 (m, 4 H), 6.39 (d, J = 15 Hz, 1 H),
IR (film): 3060, 3027, 2953, 2852, 1576, 1494, 1248, 839, 736, 691
cm .
1H NMR (CDCl3): = 7.50–7.04 (m, 10 H), 6.58 (t, J = 7.0 Hz, 1
H), 3.53 (d, J = 7.2 Hz, 2 H), 0.11 (s, 9 H).
MS: m/z = 346 (M+).
3
–
1
5.93 (dt, J = 15, 6 Hz, 1 H), 2.41–1.95 (m, 5 H), 1.70–1.11 (m, 3 H),
0
.89 (d, J = 6.7 Hz, 6 H).
Anal. Calcd for C H Se: C, 62.92; H, 7.49. Found: C, 62.68; H,
14 20
7
.21.
Anal. Calcd for C H SiSe: C, 62.54; H, 6.37. Found: C, 62.23; H,
5e
18
22
–
1
6
.11.
IR (film): 3071, 3017, 2958, 2860, 1595, 1490, 860, 740, 690 cm .
1
H NMR (CDCl ): = 7.54–7.03 (m, 5 H), 6.40 (d, J = 15 Hz, 1 H),
3
4
k
5
0
.96 (dt, J = 15, 6 Hz, 1 H), 2.40–2.10 (m, 2 H), 1.60–1.15 (m, 8 H),
.88 (t, J = 5.4 Hz, 3 H).
IR (film): 3061, 3027, 2954, 2853, 1601, 1575, 1494, 1249, 844,
7
–1
00 cm .
Synthesis 2002, No. 10, 1347–1350 ISSN 0039-7881 © Thieme Stuttgart · New York

1
350
H. Zhao, M. Cai
PAPER
Anal. Calcd for C H Se: C, 62.92; H, 7.49. Found: C, 63.17; H, References
14
20
7
.72.
(
1) (a) Mitchell, T. N.; Wickenkamp, R.; Amamria, A.;
Schneider, U. J. Org. Chem. 1987, 52, 4868. (b) Hyla-
Kryspin, I.; Gleiter, R.; Kruger, C.; Zwettler, R.; Erker, G.
Organometallics 1990, 9, 517. (c) Sun, A.; Huang, X.
Synthesis 2000, 775. (d) Yang, D. Y.; Huang, X. J.
Organomet. Chem. 1996, 523, 139. (e) Huang, X.; Ma, Y.
Synthesis 1997, 417. (f) Zhu, L. S.; Huang, Z. Z.; Huang, X.
Tetrahedron 1996, 52, 9819.
5
f
–
1
IR (film): 3070, 3018, 2960, 2862, 1598, 1489, 880, 758, 690 cm .
1
H NMR (CDCl ): = 7.64–7.12 (m, 4 H), 6.42 (d, J = 15 Hz, 1 H),
3
6
0
.03 (dt, J = 15, 6 Hz, 1 H), 2.42–2.13 (m, 2 H), 1.63–1.18 (m, 8 H),
.89 (t, J = 5.4 Hz, 3 H).
Anal. Calcd for C H ClSe: C, 55.72; H, 6.30. Found: C, 55.51; H,
1
4
19
6
.10.
(2) Xu, X.; Zheng, W.; Huang, X. Synth. Commun. 1998, 28,
165.
4
(
3) Sato, F.; Watanabe, H.; Tanaka, Y.; Yamaji, T.; Sato, M.
Tetrahedron Lett. 1983, 24, 1041.
Acknowledgement
(
4) (a) Sato, F. J. Organomet. Chem. 1985, 285, 53. (b) Sato,
F.; Urabe, H. In Grignard Reagents-New Developments:
Hydromagnesiation of Alkenes and Alkynes; Richey, H. G.
Jr., Ed.; Wiley: Chichester, 2000, 65.
We thank the National Natural Science Foundation of China and the
Natural Science Foundation of Jiangxi Province for financial sup-
port.
(
5) Eaborn, C.; Walton, D. R. M. J. Organomet. Chem. 1964, 2,
95.
(
(
6) Comasseto, J. V. J. Organomet. Chem. 1983, 253, 131.
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Organomet. Chem. 1981, 216, 287.
(
8) Raucher, S.; Hansen, M. R.; Colter, M. A. J. Org. Chem.
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(
9) Huang, X.; Zhu, L. J. Organomet. Chem. 1996, 523, 9.
(10) Braga, A. L.; Reckziegel, A.; Silveira, C. C. Synth. Commun.
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Synthesis 2002, No. 10, 1347–1350 ISSN 0039-7881 © Thieme Stuttgart · New York