S
1
Supporting Information
A Facile Synthesis of 1,1-bis(silyl)ethenes
Piotr Pawluc, Bogdan Marciniec,* Grzegorz Hreczycho, Beata Gaczewska and Yujiro Itami
Department of Organometallic Chemistry, Faculty of Chemistry, Adam Mickiewicz
University, Grunwaldzka 6, 60-780 Poznan, Poland
Table of contents
S2 Experimental procedure, spectral data and elemental analyses of 1, 2 and I
S3 Experimental procedure, spectral data and elemental analyses of II, III, IV and V.
S4 Experimental procedure, spectral data and elemental analyses of VI and 3.
S
2
Experimental
Compound 1
A 50 mL (0.359mol) of dry triethylamine in 200mL dry pentane was introduced into a flame-
dried three-necked, 500mL round-bottomed flask equipped with a magnetic stirring bar,
rubber septum cap and argon bubbling tube. To the resulting solution 9.1mL (0.161mol) of
ethylene glycol was added. 45.3mL (0.330mol) of chlorodimethylvinylsilane was
subsequently added over 1h and the reaction mixture was stirred under the flow of argon for
2h at room temperature. After the substrate disappearance was confirmed by GC, the
resulting salt was filtered off and the volatiles were removed in evaporator. Distillation under
reduced pressure (42-44
o
C/0.5mmHg) afforded 33.39g of compound 1 in 90% yield as a
colorless liquid.
1
H NMR (CDCl
3
,) δ (ppm): 0.22 (s, 12H), 3.88 (s, 4H), 5.86-5.94 (dd, J=19,
5 Hz, 2H), 5.99-6.18 (dd, J=5, 14 Hz, 2H), 6.22-6.58 (dd, J=14, 19 Hz, 2H),
13
C NMR
(CDCl
3
,)
δ
(ppm): 1.2, 64.4, 128.6, 138.5. Anal. calc. for C
10
H
22
O
2
Si
2
: C, 52.12; H, 9.62;
Found: C, 51.96; H, 9.80.
Compound 2
0.828g [RuHCl(CO)(PPh
3
)
3
] (8.7x10
-4
mol) and 20.0g (0.087mol) of compound
1
were placed
in the two-necked, 50mL flask equipped with a magnetic stirring bar and a reflux condenser.
The reaction mixture was heated for 1h at 80
o
C with stirring. The cyclic product was isolated
by “bulb to bulb” distillation to give 14.93g of compound 2 in 85% yield as a colorless liquid.
1
H NMR (CDCl
3
,) δ (ppm): 0.25 (s, 12H), 3.65 (s, 4H), 6.20 (s, 2H,),
13
C NMR (CDCl
3
,) δ
(ppm): –1.5, 66.6, 139.7, 157.7, Anal. calc. for C
8
H
18
O
2
Si
2
: C, 47.47; H, 8.96; Found: C,
47.51; H, 9.14.
Compound (I)
A solution of 2.0g (0.01mol) of compound 2 in 20mL dry THF was introduced into flame-
dried, two-necked, 100mL round-bottomed flask equipped with a magnetic stirring bar, reflux
condenser, rubber septum cap and argon bubbling tube. Then a 0.025 mol amount of
methylmagnesium iodide in dry THF was added dropwise. The reaction mixture was refluxed
under argon for 24h. The excess amount of Grignard reagent was quenched by adding
MeOH/diethyl ether solution and the mixture was extracted from ether/H
2
O. The ethereal
phase was dried over MgSO
4
and filtered, the volatiles removed in evaporator and the mixture
was passed through a silica gel column (eluent-hexane). After isolation by distillation under
argon (bp. 133
o
C/760mmHg) 1,29g of compound I was afforded in 76% yield as colorless
S
3
liquid.
1
H NMR (CDCl
3
,)
δ
(ppm): 0.10 (s, 18H), 6.29 (s, 2H).
13
C NMR (CDCl
3
)
δ
(ppm): –
0.3, 139.7, 154.7. Anal. calc. for C
8
H
20
Si
2
: C, 55.73; H, 11.69; Found: C, 56.16; H, 12.33.
Compound (II)
This compound was synthesized in the same method as the synthesis of compound I, but the
reaction mixture had to be heated for 48h. Compound II was obtained in 73% yield (1.44g) as
a colorless liquid (bp. 173
o
C/760mmHg).
1
H NMR (CDCl
3
,)
δ
(ppm): 0.07 (s, 12H), 0.53-
0.58 (q, 4H), 0.88-0.93 (t, 6H), 6.31 (s, 2H).
13
C NMR (CDCl
3
,) δ (ppm): –2.7, 7.4, 7.7,
140.9, 152.3. Anal. calc. for C
10
H
24
Si
2
: C, 59.91; H, 12.07; Found: C, 59.58; H, 12.30.
Compound (III)
This compound was synthesized by analogous reaction with phenylmagnesium bromide and
isolated by a procedure similar to that mentioned above. Distillation under reduced pressure
(110-113
o
C/0.5mmHg) afforded 2.56g of compound III in 88% yield as a colorless oil.
1
H
NMR (CDCl
3
,) δ (ppm): 0.47 (s, 12H), 6.63 (s, 2H), 7.48-7.63 (m, 10H).
13
C NMR (CDCl
3
,)
δ (ppm): –1.8, 143.8, 150.8, 128.7-138.7. Anal. calc. for C
18
H
24
Si
2
: C, 72.90; H, 8.16; Found:
C, 72.35; H, 8.13.
Compound (IV)
This compound was synthesized in essentially the same manner as I by the reaction between
2,2,4,4-tetramethyl-1,5-dioxo-2,4-disila-3-exo-methylenecycloheptane and vinylmagnesium
bromide. Compound IV was obtained in 62% yield (1.20g) as a colorless liquid (bp.
168
o
C/760mmHg).
1
H NMR (CDCl
3
,) δ (ppm): 0.19 (s, 12H), 5.65-5.73 (dd, J=4, 20 Hz,
2H), 5.96-6.02 (dd, J=4, 14 Hz, 2H), 6.14-6.26 (dd, J=14, 20 Hz, 2H), 6.38 (s, 2H).
13
C NMR
(CDCl
3
,)
δ
(ppm):
-2.2, 131.8, 139.2, 142.3, 151.1. Anal. calc. for C
10
H
20
Si
2
: C, 61.14; H,
10.24; Found: C, 60.23; H, 10.62.
Compound (V)
A solution of 2.0g (0.01mol) compound 2 in 20mL dry diethyl ether was introduced into
flame-dried, two-necked, 100mL round-bottomed flask equipped with a magnetic stirring bar,
reflux condenser, rubber septum cap and argon bubbling tube. Then a 0.03 mol amount of
allylmagnesium bromide in dry diethyl ether was added dropwise. The reaction mixture was
refluxed under argon for 48h. The excess amount of Grignard reagent was quenched by
adding MeOH/Et
2
O solution. The suspended salt was filtered off and the volatiles were
evaporated in vacuo. After isolation by distillation under reduced pressure (58
o
C/0.5mmHg)
1,51g of compound V was afforded in 68% yield as a colorless liquid.
1
H NMR (CDCl
3
,)
δ
(ppm): 0.12 (s, 12H), 1.60 (d, 4H), 4.82-4.83 (m, J=14, 5 Hz, 2H), 4.85-4.88 (m, J=17, 5 Hz,
S
4
2H), 5.67-5.82 (m, J=9, 17 Hz, 2H), 6.35 (s, 2H).
13
C NMR (CDCl
3
,)
δ
(ppm): -2.6, 24.0,
113.1, 134.8, 141.9, 151.1. Anal. calc. for C
12
H
24
Si
2
: C, 64.20; H, 10.78; Found: C, 64.63; H,
10.52.
Compound (VI)
A solution of 2.0g (0.01mol) of compound 2 in 20mL dry THF was introduced into flame-
dried, two-necked, 100mL round-bottomed flask equipped with a magnetic stirring bar, reflux
condenser, rubber septum cap and argon bubbling tube. Then a 0.03 mol amount of 3-
butenylmagnesium bromide in dry THF was added dropwise. The reaction mixture was
refluxed under argon for 72h. The excess amount of Grignard reagent was quenched by
adding MeOH/THF solution. The suspended salt was filtered off and the volatiles were
evaporated in vacuo. The obtained mixture was injected into a silica gel column (eluent-
hexane) and compound VI was isolated by reduced pressure distillation (60
o
C/0.5mmHg) in
55% yield (1.37g) as a colorless liquid.
1
H NMR (CDCl
3
,) δ (ppm): 0.11 (s, 12H), 0.65-0.77
(t, 4H), 2.00-2.06 (m, 4H), 4.91-4.87 (m, J=10, 5 Hz, 2H), 4.95-5.02 (m, J=17, 5 Hz, 2H),
5.82-5.95 (m, J=10, 16 Hz, 2H), 6.33 (s, 2H).
13
C NMR (CDCl
3
,) δ (ppm): -1.9, 15.3, 28.1,
112.6, 141.3, 141.6, 151.9. Anal. calc. for C
14
H
28
Si
2
: C, 66.58; H, 11.18; Found: C, 64.56; H,
11.30.
Compound 3
3.0g of compound 2 (0.015mol) in 10mL of THF were placed in the two-necked, 50mL flask
equipped with a magnetic stirring bar and a reflux condenser. Then 0.29mL (0.016mol) of
water and several drops of aqueous solution of HCl were added. The reaction mixture was
refluxed for 4h with stirring. The solvent was evaporated in vacuo and the cyclic product was
isolated by distillation under reduced pressure (68
o
C/0.5mmHg) to give 2.06g of 4 in 88%
yield.
1
H NMR (CDCl
3
,)
δ
(ppm): 0.28 (s, 24H), 6.19 (s, 4H).
13
C NMR (CDCl
3
,)
δ
(ppm): 1.1,
139.9, 156.6. Anal. calc. for C
12
H
28
O
2
Si
4
: C, 45.60; H, 8.86; Found: C, 45.56; H, 8.81.