Hydrogenation of silyl-substituted alkynes using diimide: Application to the synthesis of saturated sila-macrocycles

Article abstract of DOI:10.1246/cl.2000.1416

The hydrogenation of bistrimethylsilylactylene, bis(trimethylsilyl)-1,3-diynes, and related silylalkynes giving the corresponding saturated compounds were achieved by using diimide prepared in situ from p-toluenesulfonyl hydrazide in diglyme. The present

Full text of DOI:10.1246/cl.2000.1416

1
416
Chemistry Letters 2000
Hydrogenation of Silyl-Substituted Alkynes Using Diimide:
Application to the Synthesis of Saturated Sila-Macrocycles
Eunsang Kwon, Kenkichi Sakamoto, Chizuko Kabuto, and Mitsuo Kira*
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578
(Received October 11, 2000; CL-000923)
The hydrogenation of bistrimethylsilylactylene, bis(tri-
methylsilyl)-1,3-diynes, and related silylalkynes giving the cor-
responding saturated compounds were achieved by using
diimide prepared in situ from p-toluenesulfonyl hydrazide in
diglyme. The present method was applicable to the synthesis of
saturated 12- and 18-membered oligosilacycloalkanes.
We have found that the hydrogenation of various silyl-
alkynes with diimide provides a convenient and versatile
method for the syntheses of the corresponding saturated com-
pounds.1 The results are particularly interesting, because
though various silylalkynes are prepared rather easily, their
hydrogenation by other conventional methods such as the
hydrogenation with transition metal catalysts was
unsuccessful.3 The present method was applied to the synthesis
of saturated sila-macrocycles such as 1,4,7,10-tetrasilacyclo-
dodecane and 1,4,7,10,13,16-hexasilacyclooctadecane.
,2
Typically, the hydrogenation of bis(trimethylsilyl)acetylene
1) with diimide was performed as follows: A mixture of 1 (2.00
8
(
82% yields, respectively, by the hydrogenation of the corre-
9
9
g, 11.8 mmol) and p-toluenesulfonyl hydrazide (4.38 g, 23.5
mmol) in diglyme (20 mL) was heated under reflux for 10 h.
After cooling the mixture to room temperature, water (20 mL)
was added. The mixture was neutralized with aqueous NaHCO3
and then extracted with pentane. The organic layer was dried
over anhydrous sodium sulfate. Evaporation of solvents fol-
lowed by silicagel column chromatography gave pure 1,2-
bis(trimethylsilyl)ethane (2, 1.70 g, 83% yield) as a colorless oil
sponding cyclic oligosilaalkynes 13 and 14 (eq 2).
(Table 1, entry 1). The reduction of 1 with an equimolar amount
of p-toluenesulfonyl hydrazide afforded a mixture of the corre-
sponding bissilylethane and ethylene.
The present method for the synthesis of silaalkanes is useful
because the precursor silylalkynes are obtained easily by the
reactions of ethynyllithiums and ethynyl Grignard reagents with
halosilanes. Not only 1,2-bissilylethanes but 1,3-bissilyl- and
Structures of 11 and 12 were determined by spectroscopic,
10,11
elemental, and X-ray crystallographic analyses.
As shown in
Figure 1, 11 and 12 were found by X-ray crystallography to have
roughly rectangular molecular skeletons, where the deviations of
all silicon atoms in 11 and 12 from the least squares planes were
within 0.08 Å and 0.86 Å, respectively.
1
,4-bissilylalkanes were prepared by the hydrogenation of the
corresponding 3-silylpropargylsilanes and 1,4-bis(trialkylsilyl)-
diynes, respectively. These results are summarized in Table 1.
Phenyl groups in 12 were completely converted into chlo-
rine, hydrogen, and fluorine atoms by conventional procedures to
give the corresponding new macrocyclic silaalkanes 15, 16, and
4
The hydrogenation of tetrakis(trimethylsilylethynyl)silane 7
afforded tetrakis(2-trimethylsilylethyl)silane 8 in 88% yield.
Dendrimeric silaalkanes may be synthesized by the present
hydrogenation of the corresponding dendrimers having
silaalkyne skeletons.5 No cleavage of Si–Si bonds occurred dur-
1
2
17, respectively (Scheme 1). Chlorination of 12 was performed
using hydrogen chloride in the presence of aluminum chloride to
give 15 in 92% yield. Reduction of 15 by lithium aluminum
hydride at room temperature afforded hexasilacyclooctadecane
16 in 87% yield. Compound 15 was converted into the fluorinat-
ed derivative 17 in 81% yield by fluorination using antimony(III)
fluoride at room temperature. The highly symmetric structures
6
ing the hydrogenation of bis(trimethylsilylethynyl)disilane 9
using diimide; the reaction gave the corresponding saturated
7
compound 10 in 77% yield (Table 1, entry 5).
Crown-like silaalkanes 11 and 12 were prepared in 74 and
Copyright © 2000 The Chemical Society of Japan

Chemistry Letters 2000
1417
3
–
06 Hz). The 19F NMR spectrum shows a sharp singlet at δ
29
1
138.0 with satellite signals due to Si nuclei ( J
= 360 Hz).
Si–F
Because these sila-macrocycles have flexible structures and func-
tional silicon moieties, the compounds would be employed for
new components in the supramolecular chemistry.
References and Notes
1
For a recent review, see: D. J. Pasto and R. T. Taylor, Org. React.,
4
0, 91 (1991).
2
R. S. Dewey and E. E. von Tamelene, J. Am. Chem. Soc., 83, 3729
(1961); T. N. Mitchell and B. Kowall, J. Organomet. Chem., 481, 137
(1994).
3
4
5
6
The hydrogenation with hydrogen in the presence of various transition
metal catalysts (RhCl(PPh ) , Pd/C, Pt/C, etc.) was unsuccessful.
3
3
N. V. Komarov and O. G. Yarosh, Zh. Obshch. Khim., 37, 264
1967).
T. Matsuo, K. Uchida, and A. Sekiguchi, Chem. Commun., 1999,
799.
(
1
Compound 9 was prepared by the reaction of [(trimethylsilyl)-
ethynyl]magnesium bromide with 1,1-dichloro-1,1,2,2-tetramethyl-
disilane in THF. 9: 78% yield, colorless crystals; mp 41.8–43.6 ˚C;
1
13
H NMR (C D , 298 K, δ) 0.13 (s, 18 H), 0.34 (s, 12 H); C NMR
6
6
2
9
(C D , 298 K, δ) –3.0, –0.4, 111.9, 117.3; Si NMR (C D , 298 K, δ)
6
6
6
6
+
–
38.1, –19.1; MS (70 eV) m/z (%) 310 (M , 32), 295 (78), 237 (32),
1
55 (68), 140 (36), 73 (100); HRMS Calcd for C H Si : 310.1425.
14
30
4
Found: 310.1421.
Yu. E. Ovchinnikov, V. E. Shklover, Yu. T. Struchkov, Yu. P.
7
Polyakov, and L. E. Guselnikov, Makromol. Chem., 187, 2011
(
1986).
1
8
11: mp 225.8–226.0 °C; H NMR (CDCl , 298 K, δ) 1.04 (s, 16 H),
7
1
8
3
13
.25–7.39 (m, 40 H); C NMR (CDCl , 298 K, δ) 2.5, 127.7, 129.1,
3
29
34.9, 135.9; Si NMR (CDCl , 298 K, δ) –3.8; MS (70 eV) m/z (%)
3
+
40 (M , 9), 522 (15), 468 (87), 343 (56), 259 (100), 183 (50); Anal.
Calcd for C H Si : C, 79.94; H, 6.71%; Found: C, 79.90; H, 6.97%.
56
56
4
1
1
7
1
2: mp 256.4 °C; H NMR (CDCl , 298 K, δ) 1.00 (s, 24 H),
3
13
.19–7.44 (m, 60 H); C NMR (CDCl , 298 K, δ) 3.7, 127.8, 129.2,
3
35.0, 135.3; 29Si NMR (CDCl , 298 K, δ) –3.2; Anal. Calcd for
3
C H Si : C, 79.94; H, 6.71%; Found: C, 79.72; H, 6.72%.
84
84
6
9
1
R. Bortolin, B. Parbhoo, and S. S. D. Brown, J. Chem. Soc., Chem.
Commun., 1988, 1079; M. Unno, T. Saito, and H. Matsumoto, Chem.
Lett., 1999, 1235.
0
Intensities of reflections were collected on a Rigaku/MSC Mercury
CCD diffractometer using Mo Kα radiation (λ = 0.71069 Å). The
structures were solved by direct method using SIR92. Crystal data
for 11: C H Si ·2CHCl , fw = 1080.16, monoclinic, space group
5
6
56
4
3
P2 /c, a = 12.5464(6) Å, b = 21.075(1) Å, c = 22.394(1) Å, β =
1
3
3
1
02.6227(5)° V = 5778.3(6) Å , Z = 2, d = 1.212 g/cm , tempera-
calc
ture 190 K. Full matrix least-squares refinement yielded the final R
value of 0.080 (Rw = 0.085) for 4750 independent reflections [I >
3
.00σ(I)]. Crystal data for 12: C H Si ·4H O, fw = 1334.16, mono-
84 84 6 2
clinic, space group P2 /n, a = 12.0616(7) Å, b = 21.008(1) Å, c =
1
g/cm , temperature 293 K. Full matrix least-squares refinement
yielded the final R value of 0.061 (Rw = 0.074) for 4329 independent
reflections [I > 5.00σ(I)].
Compound 12 was obtained previously by the hydrosilylation of
diphenylbis(2-diphenylsilylethyl)silane with diphenylbis[2-diphenyl-
1
3
5.987(1) Å, β = 101.3450(7)° V = 3971.8(4) Å , Z = 2, d = 1.115
calc
3
1
1
(
vinyl)silylethyl]silane under highly dilute conditions in 1.8% yield;
M. Ichinohe, Y. Hayashi, and M. Kira, 73th Annual Meeting of the
Chemical Society of Japan, Morioka, September 1997, Abstr., No.
3
D801.
1
1
2
15: mp 162.2–164.9 °C; H NMR (CD Cl , 298 K, δ) 1.23 (s, 24 H);
2
2
1
3
29
C NMR (CD Cl , 298 K, δ) 13.4; Si NMR (CD Cl , 298 K, δ)
2
2
2
2
+
31.3; MS (70 eV) m/z (%) 761 (M , trace), 71 (37), 58 (100); HRMS
3
5
37
Calcd for C H Cl9 Cl Si : 761.6667. Found: 761.6642. 16: mp
12
24
3
6
1
1.3–23.1 °C; H NMR (CDCl , 298 K, δ) 0.71–0.72 (m, 24 H), 3.68
3
29
bs, 12H); 13C NMR (CDCl , 298 K, δ) 3.5; Si NMR (CDCl , 298
3 3
+
of these silacycles were confirmed by H, 13C, and 29Si NMR
1
1
13
C12H36Si6: 348.1433. Found: 348.1432. 17: mp 73.4 °C; H NMR
spectroscopy. In the C NMR spectrum of 17, a single methyl-
13
(
THF-d , 298 K, δ) 0.97 (bs, 24 H); C NMR (THF-d , 298 K, δ) 2.1
8
8
ene carbon resonance was observed at δ 2.1 as a triplet due to the
2
29
1
(
t, J = 16 Hz); Si NMR (THF-d , 298 K, δ) –1.5 (t, J
= 306
C–F
8
Si–F
2
19
1
coupling with two equivalent fluorine atoms ( J
= 16 Hz).
Hz); F NMR (THF-d , 298 K, δ) –138.0 (s, J
= 306 Hz); MS
C–F
8
Si–F
+
The 29Si NMR signal of 17 appeared at δ –1.5 as a triplet due to
(70 eV) m/z (%) 564 (M , 3), 295 (71), 207 (100), 193 (50), 163 (58);
HRMS Calcd for C H F Si : 564.0302. Found: 564.0325.
1
12 24 12
6
the coupling with the two equivalent fluorine atoms ( J
=
Si–F