Silicon-carbon unsaturated compounds. 62. Reactions of silenes produced thermally from pivaloyl- and adamantoyltris(trimethylsilyl)silane with mono(silyl)acetylenes

Article abstract of DOI:10.1016/S0022-328X(00)00476-9

Thermolysis of pivaloyltris(trimethylsilyl)silane (1a) with tert-butyldimethylsilylacetylene at 120°C gave 2-tert-butyl-3-tert-butyldimethylsilyl-2-trimethylsiloxy-1,1-bis(trimethylsilyl) -1-silacyclobut-3-ene (2a). Similar treatment of adamantoyltris(trimethylsilyl)silane (1b) at 120°C produced 2-adamantyl-3-tert-butyldimethylsilyl-2-trimethylsiloxy-1,1-bis(trimethylsilyl)- 1-silacyclobut-3-ene (2b). Thermolysis of 1a with tert-butyldimethylsilylacetylene at 160°C, however, gave 1-tert-butyl-1-(tert-butyldimethylsilyl)-3-[(trimethylsiloxy)bis(trimethylsilyl) silyl]-1,2-propadiene (3a), along with 1:2 adduct (4a). Similar reaction of 1b gave 1-adamantyl-1-(tert-butyldimethylsilyl)-3-[(trimethylsiloxy)bis(trimethylsilyl) silyl]-1,2-propadiene (3b) similar to 3a, together with 1:2 adduct (4b). Thermolysis of 1a and 1b in the presence of dimethylphenylsilylacetylene or triphenylsilylacetylene at 120°C produced [2 + 2] cycloadducts arising from the reaction of silenes generated thermally from 1a and 1b with mono(silyl)acetylenes analogous 2a and 2b, along with small amounts of 1:2 adducts. At 160°C, the similar treatment of 1a and 1b afforded propadiene derivatives arising from the ring opening reactions of [2 + 2] cycloadducts, in addition to 1:2 adducts.

Full text of DOI:10.1016/S0022-328X(00)00476-9

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Journal of Organometallic Chemistry 611 (2000) 248–255
Silicon–carbon unsaturated compounds. 62. Reactions of silenes
produced thermally from pivaloyl- and
adamantoyltris(trimethylsilyl)silane with mono(silyl)acetylenes
Akinobu Naka, Mitsuo Ishikawa *
Department of Chemical Technology, Kurashiki Uni6ersity of Science and the Arts, 2640 Nishinoura, Tsurajima-cho, Kurashiki,
Okayama 712-8505, Japan
Received 2 March 2000; accepted 30 March 2000
Abstract
Thermolysis of pivaloyltris(trimethylsilyl)silane (1a) with tert-butyldimethylsilylacetylene at 120°C gave 2-tert-butyl-3-tert-
butyldimethylsilyl-2-trimethylsiloxy-1,1-bis(trimethylsilyl)-1-silacyclobut-3-ene (2a). Similar treatment of adamantoyl-
tris(trimethylsilyl)silane (1b) at 120°C produced 2-adamantyl-3-tert-butyldimethylsilyl-2-trimethylsiloxy-1,1-bis(trimethylsilyl)-
1-silacyclobut-3-ene (2b). Thermolysis of 1a with tert-butyldimethylsilylacetylene at 160°C, however, gave 1-tert-butyl-1-(tert-
butyldimethylsilyl)-3-[(trimethylsiloxy)bis(trimethylsilyl)silyl]-1,2-propadiene (3a), along with 1:2 adduct (4a). Similar reaction of
1b gave 1-adamantyl-1-(tert-butyldimethylsilyl)-3-[(trimethylsiloxy)bis(trimethylsilyl)silyl]-1,2-propadiene (3b) similar to 3a, to-
gether with 1:2 adduct (4b). Thermolysis of 1a and 1b in the presence of dimethylphenylsilylacetylene or triphenylsilylacetylene at
120°C produced [2+2] cycloadducts arising from the reaction of silenes generated thermally from 1a and 1b with mono(si-
lyl)acetylenes analogous 2a and 2b, along with small amounts of 1:2 adducts. At 160°C, the similar treatment of 1a and 1b
afforded propadiene derivatives arising from the ring opening reactions of [2+2] cycloadducts, in addition to 1:2 adducts. © 2000
Elsevier Science S.A. All rights reserved.
Keywords: Silene; Acylpolysilane; Thermolysis; Silyl acetylene
thylsilyl)silane also react with trimethylsilylacetylene to
give the ring-opened products derived from [2+2] cy-
1. Introduction
cloadducts [13]. Similar reactions of the silenes formed
Acylpolysilanes are useful precursors for the synthe-
from pivaloyl- and adamantoyl-tris(trimethylsilyl)-
sis of silenes, and many papers concerning the synthesis
silane, however, produce [2+2] cycloadducts and the
and reactions of silenes produced by the photolysis
ring-opened products [13]. In a previous paper, we
[1–3] of the acylpolysilanes have been published to
reported the [2+2] cycloadducts to be 2-tert-butyl- and
date. It is also well-known that a Peterson-type reaction
2 - adamantyl - 2 - (trimethylsiloxy) - 1,1,4 - tris(trimethyl-
of the acylpolysilanes offers a convenient route to the
synthesis of silenes [4–7].
We have found that the thermolysis of acyl-
silyl)-1-silacyclobut-3-ene. However, this has turned out
to be an erroneous structural assignment. Careful stud-
1
ies of the 500 MHz H-NMR spectral data and also the
tris(trimethylsilyl)silanes readily affords silenes [8–13],
and the silenes thus formed react with olefins [10],
dienes [10], and carbonyl compounds [12] to give the
respective adducts in high yields. The silenes produced
thermally from acetyl- and isopropionyl-tris(trime-
chemical reaction indicated that these compounds must
be regioisomers, 2-tert-butyl- and 2-adamantyl-2-
(trimethylsiloxy)-1,1,3-tris(trimethylsilyl)-1-silacyclobut-
3-ene.
In order to learn more about chemical behavior of
[2+2] cycloadducts arising from the silenes produced
thermally from acylpolysilanes with alkynes, we investi-
gated the co-thermolysis of pivaloyl- and adamantoyl-
tris(trimethylsilyl)silane with mono(silyl)acetylenes.
* Corresponding author: Tel.: +81-86-4401086; fax: +81-86-
4401062.
E-mail address: mishika@chem.kusa.ac.jp (M. Ishikawa).
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00476-9

A. Naka, M. Ishikawa / Journal of Organometallic Chemistry 611 (2000) 248–255
249
2. Results and discussion
0.23 (Mec) and 7.05 ppm (Hg) couple with Si4 at 5.4
ppm and Si1 at −10.6 ppm, respectively. These results
are wholly consistent with the structure proposed for
2b. In contrast to 2a, product 2b is stable to moisture
and oxygen in air.
When the cothermolysis of pivaloyltris(trimethylsi-
lyl)silane (1a) with tert-butyldimethylsilylacetylene was
carried out in a sealed glass tube at 120°C for 12 h,
2-tert-butyl-3-tert-butyldimethylsilyl-2-trimethylsiloxy-
1,1-bis(trimethylsilyl)-1-silacyclobut-3-ene (2a) was ob-
tained in 69% yield, along with a 23% yield of the
starting compound 1a. The 13C-NMR spectrum of 2a
reveals resonances due to two methylsilyl carbons, three
kinds of trimethylsilyl carbons, one quaternary sp3 car-
bon, two kinds of olefinic carbons, as well as carbons
attributed to two tert-butyl groups. Its 29Si-NMR spec-
trum indicates the presence of five nonequivalent silicon
atoms at −18.6, −13.6, −9.4, −7.5 and 5.7 ppm.
These results are wholly consistent with the structure
proposed for 2a. Product 2a is rather unstable toward
moisture and oxygen in air. Thus, when 2a was allowed
to stand in air for a long time, it gradually decomposed
to give unidentified products.
Recrystallization of 2b from ethanol afforded a single
crystal, and we carried out X-ray crystallographic anal-
ysis of this crystal. However, we could not obtain any
information concerning the structure of 2b, because 2b
probably decomposed by irradiating X-ray. Conse-
quently, the structure of 2b was verified by mass and
NMR spectrometric analysis, as well as by elemental
analysis.
The formation of products 2a and 2b can be best
understood in terms of [2+2] cycloaddition of the
silenes produced thermally from the corresponding
acylpolysilanes 1a and 1b with tert-butyldimethylsily-
lacetylene. The fact that no regioisomers were detected
in the reaction mixture indicated that [2+2] cycloaddi-
tion of the silenes with the acetylene proceeded with
high regiospecificity [3,14].
A similar reaction of adamantoyltris(trimethylsi-
lyl)silane (1b) with tert-butyldimethylsilylacetylene pro-
ceeded to give a product similar to 2a, 2-adamantyl-
3-tert-butyldimethylsilyl-2-trimethylsiloxy-1,1-bis(trime-
thylsilyl)-1-silacyclobut-3-ene (2b) as white crystals, in
63% isolated yield, together with 35% of the starting
compound 1b (Scheme 1). No other volatile products
Next, we carried out the reaction of 1a with tert-
butyldimethylsilylacetylene at 160°C for 12 h. Thus,
treatment of 1a with tert-butyldimethylsilylacetylene at
160°C gave 1-tert-butyl-1-(tert-butyldimethylsilyl)-3-
[(trimethylsiloxy)bis(trimethylsilyl)silyl]-1,2-propadiene
(3a) and 1:2 adduct (4a) in 90 and 6% yields, respec-
tively. The products 3a and 4a could readily be isolated
by column chromatography (see Section 3). The struc-
1
were detected in the reaction mixture. The H-NMR
spectrum of 2b shows the presence of two kinds of
methylsilyl protons at 0.11 and 0.15 ppm, three kinds of
trimethylsilyl protons at 0.22, 0.23 and 0.24 ppm, in
addition to adamantyl protons at 1.64–2.04 ppm, tert-
butyl protons at 0.97 ppm and olefinic protons at 7.05
ppm. The 29Si-NMR spectrum of 2b reveals five reso-
nances at −18.2, −13.6, −10.6, −7.6, and 5.4 ppm
as expected. Furthermore, we measured the 1H-29Si
COSY NMR spectrum to establish the structure of 2b.
Two trimethylsilyl protons at 0.22 and 0.24 ppm (Mea,
Meb) couple with a ring silicon atom at −10.6 ppm
(Si1) and trimethylsilyl silicon atoms at −18.2 and
−13.6 ppm (Si2, Si3), while two methylsilyl protons at
0.11 and 0.15 ppm (Med, Mee) and tert-butyl protons at
0.97 ppm couple with Si5 at −7.6 ppm. The protons at
1
tures of 3a and 4a were verified by mass, IR, and H-,
13C- and 29Si-NMR spectrometry. Mass spectrometric
analysis of 4a showed that this molecule was formed
from one molecule of 1a and two molecules of tert-
butyldimethylsilylacetylene. The formation of the 1:2
adduct similar to 4a has been found in the reaction of
the silenes produced from acylpolysilanes with
trimethylsilylacetylene. Similarly, the reaction of 1b
with tert-butyldimethylsilylacetylene at 160°C for
12 h afforded 1-adamantyl-1-tert-butyldimethylsilyl-3-
[(trimethylsiloxy)bis(trimethylsilyl)silyl]-1,2-propadiene
(3b) and 1:2 adduct (4b) in 90 and 4% yield, respec-
tively. IR spectra for 3a and 3b show characteristic
absorptions at 1882 and 1889 cm−1, respectively, due
to the allenic structure. 13C-NMR spectra reveal a
signal at 209.20 ppm for 3a and 209.80 ppm for 3b, due
to the central allenic carbon atoms. Products 3a and 3b
may be formed via a 1,2-trimethylsiloxy shift in [2+2]
cycloadducts 2a and 2b as shown in Scheme 2.
Indeed, when compound 2a was heated at 160°C for
12 h in a sealed glass tube, it was found that 2a
Scheme 1.

250
A. Naka, M. Ishikawa / Journal of Organometallic Chemistry 611 (2000) 248–255
Scheme 2.
isomerized completely to give 3a. In contrast to these
results, we previously reported that the thermolysis of
1a and 1b with trimethylsilylacetylene at 140°C af-
forded [2+2] cycloadducts, 2-tert-butyl- and 2-
adamantyl-2-trimethylsiloxy-1,1,4-tris(trimethylsilyl)-1-
silacyclobut-3-ene, in addition to ring-opened products
and 1:2 adducts, analogous to 3a and 4a, respectively.
We suspected that erroneous structure assignment had
been made for the [2+2] cycloadducts produced from
the reactions of 1a and 1b with trimethylsilylacetylene.
Therefore, we reinvestigated the thermal properties of
[2+2] cycloadducts obtained previously. Thus, when
the [2+2] cycloadducts were heated in a sealed glass
tube at 160°C, the ring-opened products, 1-tert-butyl-
and 1-adamantyl-3-[(trimethylsiloxy)bis(trimethylsilyl)-
silyl]-1-trimethylsilyl-1,2-propadiene were obtained in
almost quantitative yields. These results clearly indicate
that a trimethylsilyl group should be on the C3 position
in the silacyclobutene ring, but not on the C4 position
as reported previously. Consequently, the structures of
the [2+2] cycloadducts must be 2-tert-butyl- and 2-
adamantyl-2-(trimethylsiloxy)-1,1,3-tris(trimethylsilyl)-
1-silacyclobut-3-ene, analogous to 2a and 2b (Scheme
3).
with 10% of the starting compound 1b. With
triphenylsilylacetylene, 1a reacted also at 120°C to give
[2+2] cycloadduct, 2-tert-butyl-2-trimethylsiloxy-1,1-
bis(trimethylsilyl)-3-triphenylsilyl-1-silacyclobut-3-ene
(7a) and 1:2 adduct (8a) in 40 and 9% yields, along with
41% of the unchanged 1a, while 1b reacted with
triphenylsilylacetylene to give 2-adamantyl-2-trimethyl-
siloxy - 1,1 - bis(trimethylsilyl) - 3 - triphenylsilyl - 1 - sila-
cyclobut-3-ene (7b) and 1:2 adduct (8b) in 42 and 9%
yields, together with 48% of the starting compound 1b.
The structures of products 5a, 5b, 6a, 6b, 7a, 7b, 8a and
8b were confirmed by mass, IR, and 1H-, 13C-, and
29Si-NMR spectrometric analysis (Scheme 4).
At 160°C, 1a and 1b reacted with dimethylphenylsilyl-
acetylene and triphenylsilylacetylene, respectively, to
give the propadiene derivatives as main products. In all
cases, no [2+2] cycloadducts were detected in the
reaction mixtures. Presumably, the silacyclobutene
derivatives once formed undergo isomerization to give
the propadiene derivatives. Thus, the cothermolysis of
1a with dimethylphenylsilylacetylene at 160°C gave 1-
tert-butyl-1-dimethylphenylsilyl-3-[(trimethylsiloxy)bis-
Phenyl-substituted silylacetylenes also react with the
silenes formed thermally from 1a and 1b. Thus, the
thermolysis of 1a with dimethylphenylsilylacetylene at
120°C for 12
h afforded 2-tert-butyl-3-dimethyl-
phenylsilyl-2-trimethylsiloxy-1,1-bis(trimethylsilyl)-1-
silacyclobut-3-ene (5a) and 1:2 adduct (6a) in 52 and
20% yields, respectively. In this reaction 5% of the
starting acylpolysilane 1b was recovered unchanged.
The similar reaction of 1b with dimethylphenylsilyl-
acetylene gave 2-adamantyl-3-dimethylphenylsilyl-2-
trimethylsiloxy-1,1-bis(trimethylsilyl)-1-silacyclobut-3-
ene (5b) and 1:2 adduct (6b) in 53 and 13% yields, along
Scheme 3.

A. Naka, M. Ishikawa / Journal of Organometallic Chemistry 611 (2000) 248–255
251
3. Experimental
All thermal reactions were carried out in a degassed
sealed tube (1.0 cmØ×15 cm). Yields for 2a, 2b, 3a,
3b, 4a, 5a, 5b, 6a, 6b, 7a and 7b were determined by
analytical GLC with the use of eicosane as an internal
standard, on the basis of the acylpolysilanes used.
Yields of the products 4b, 8a, 8b, 9a, 9b, 10a and 10b
were calculated on the basis of the isolated products.
NMR spectra were recorded on a JNM-LA300 spec-
trometer and JNM-LA500 spectrometer. Infrared spec-
tra were recorded on a JEOL Model JIR-DIAMOND
20 infrared spectrophotometer. Low- and high-resolu-
tion mass spectra were measured on a JEOL Model
JMS-700 instrument. Gel permeation chromatographic
separation was performed with a Model LC-908 Recy-
cling Preparative HPLC (Japan Analytical Industry Co.
Ltd.). Melting point were measured with a Yanaco-
MP-S3 apparatus. Column chromatography was per-
formed by using Wakogel C-300 (WAKO). THF used
as a solvent was distilled under nitrogen from sodium/
benzophenone ketyls. Acylpolysilanes 1a and 1b were
prepared according to the method reported by Brook et
al. [8,15].
Scheme 4.
3.1. Preparation of triphenylsilylacetylene
(trimethylsilyl)silyl]-1,2-propadiene (9a) in 74% yield,
along with an 11% yield of 6a. A similar cothermolysis
of 1b with dimethylphenylsilylacetylene produced a
propadiene derivative (9b) and 6b in 72 and 11% yields,
respectively.
In a 500 ml-three necked flask was placed a solution
of ethynyl-Grignard reagent prepared from 0.10 mol of
ethylmagnesium bromide and acetylene in 200 ml of
THF. To this was added 30.13 g (0.10 mol) of chloro-
triphenylsilane in 70 ml of THF through a dropping
funnel over a period of 1 h. The mixture was refluxed
for 3 h and then hydrolyzed with water. The organic
layer was separated and the aqueous layer was ex-
tracted with ether. The organic layer and the extracts
were combined, washed with water, and dried over
magnesium sulfate. After the solvent was evaporated,
triphenylsilylacetylene (19.878 g, 70%) was isolated by
column chromatography: MS m/z 284 (M+); IR 3264,
3068, 3050, 3023, 2036, 1484, 1429, 1264, 1114, 740,
Similar thermolysis of 1a and 1b with triphenylsilyl-
acetylene at 160°C proceeded to give the propadiene
derivatives and 1:2 adducts. Treatment of 1a with
triphenylsilylacetylene afforded 1-tert-butyl-3-[(trime-
thylsiloxy)bis(trimethylsilyl)silyl] - 1 - triphenylsilyl - 1,2-
propadiene (10a) and 8a in 58 and 30% yields, while 1b
with triphenylsilylacetylene produced 1-adamantyl-3-
[(trimethylsiloxy)bis(trimethylsilyl)silyl]-1-triphenylsilyl-
1,2-propadiene (10b) in 43% yield, in addition to a 43%
yield of 8b. In the thermolysis of 1a and 1b in the
presence of the silylacetylenes at 160°C, only propadi-
ene derivatives and 1:2 adducts were obtained, but no
other volatile products were detected in the reaction
mixtures. The structures of 9a, 9b, 10a, and 10b were
1
711, 696 cm−1; H-NMR l(CDCl3) 2.82 (s, 1H, HC),
7.41–7.49 (m, 9H, phenyl ring protons), 7.70–7.74 (m,
6H, phenyl ring protons); 13C-NMR l(CDCl3) 85.30,
97.77 (sp carbon), 128.03, 130.08, 132.78, 135.49
(phenyl ring carbons); 29Si-NMR l(CDCl3) −28.9.
Anal. Calc. for C20H16Si: C, 84.46; H, 5.67. Found: C,
84.37; H, 5.58%.
1
verified by mass, H-, 13C- and 29Si-NMR spectrometric
analysis, as well as by elemental analysis.
In conclusion, the thermolysis of acylpolysilanes 1a
and 1b with mono(silyl)acetylenes at 120°C proceeded
to give [2+2] cycloadducts arising from the addition of
the silenes produced thermally from acylpolysilanes to
mono(silyl)acetylenes as main products. At 160°C,
however, 1a and 1b reacted with mono(silyl)acetylenes
to give the propadiene derivatives which were probably
produced by the ring-opening reaction of the
silacyclobut-3-enes.
3.1.1. Thermolysis of 1a with
tert-butyldimethylsilylacetylene at 120°C
A mixture of 0.1679 g (0.506 mmol) of 1a and 0.0700
g (0.500 mmol) of tert-butyldimethylsilylacetylene was
heated in a sealed glass tube at 120°C for 12 h. The
mixture was analyzed by GLC as being 2a (69% yield),
along with the starting compound 1a (23%). Product 2a

252
A. Naka, M. Ishikawa / Journal of Organometallic Chemistry 611 (2000) 248–255
0.09 (s, 3H, MeSi), 0.10 (s, 6H, Me2Si), 0.12 (s, 9H,
Me3Si), 0.17 (s, 9H, Me3Si), 0.19 (s, 9H, Me3Si), 0.23 (s,
3H, MeSi), 0.93 (s, 9H, t-Bu), 0.94 (s, 18H, t-Bu), 4.94
(s, 1H, HCO), 5.81 (s, 1H, HCꢀC); 13C NMR l(CDCl3)
−4.69 (MeSi), −4.64 (MeSi), −2.30 (MeSi), −0.60
(Me3Si), −0.40 (Me3Si), −0.19 (MeSi), 1.27 (Me3Si),
16.57 (CMe3), 18.88 (Me3C), 26.08 (Me3C), 27.29
(CMe3), 28.54 (Me3C), 36.56 (CMe3), 85.37 (CO),
110.25, 119.14 (sp carbons), 136.88, 166.26 (olefinic
carbons); 29Si-NMR l(CDCl3) −73.0, −14.0, −13.7,
−9.6, −1.7, 14.4. Anal. Calc. for C30H68OSi6: C,
58.74; H, 11.17. Found: C, 58.50; H, 11.27%.
was isolated by column chromatography: MS m/z 472
(M+); IR 2956, 2896, 2858, 1390, 1361, 1251, 1095,
;
1039, 898, 835, 754, 684, 624 cm−1 1H-NMR
l(CDCl3) 0.10 (s, 3H, MeSi), 0.13 (s, 3H, MeSi), 0.20
(s, 18H, Me3Si), 0.22 (s, 9H, Me3Si), 0.95 (s, 9H, t-Bu),
1.07 (s, 9H, t-Bu), 7.06 (s, 1H, HCꢀC); 13C-NMR
l(CDCl3) −3.80, −1.91 (MeSi), 1.21, 1.36, 3.04
(Me3Si), 18.14 (CMe3), 27.68 (Me3C), 29.62 (Me3C),
38.01 (CMe3), 96.57 (CO), 153.07, 177.05 (olefinic
carbons); 29Si-NMR l(CDCl3) −18.6, −13.6, −9.4,
−7.5, 5.7; exact mass calc. for C22H52OSi5 ([M+])
472.2865, found 472.2876.
3.1.4. Thermolysis of 1b with
tert-butyldimethylsilylacetylene at 160°C
3.1.2. Thermolysis of 1b with
tert-butyldimethylsilylacetylene at 120°C
A mixture of 0.1455 g (0.355 mmol) of 1b and 0.0730
g (0.521 mmol) of tert-butyldimethylsilylacetylene was
heated at 160°C for 12 h. The mixture was analyzed by
GLC as being 3b (90% yield). Products 3b and 4b
(0.0099 g, 4%) were isolated by column chromatogra-
phy. For 3b: MS m/z 550 (M+); IR 2955, 2904, 2850,
A mixture of 0.1689 g (0.412 mmol) of 1b and 0.0756
g (0.540 mmol) of tert-butyldimethylsilylacetylene was
heated in a sealed glass tube at 120°C for 12 h. The
mixture was analyzed by GLC as being 2b (63% yield),
along with the starting compound 1b (35%). Product 2b
were isolated by column chromatography: MS m/z 550
(M+); IR 2956, 2900, 2854, 1471, 1243, 1079, 831, 690,
1
1889, 1407, 1251, 1054, 836, 757, 682 cm−1; H-NMR
1
624 cm−1; H-NMR l(CDCl3) 0.11 (s, 3H, MeSi), 0.15
l(CDCl3) 0.10 (s, 9H, Me3Si), 0.13 (s, 9H, Me3Si), 0.14
(s, 3H, MeSi), 0.15 (s, 9H, Me3Si), 0.22 (s, 3H, MeSi),
0.94 (s, 9H, t-Bu), 1.63–1.98 (m, 15H, Ad), 4.55 (s, 1H,
HCꢀC); 13C-NMR l(CDCl3) −2.14, −1.90 (MeSi),
−1.14, −1.10, 2.30 (Me3Si), 19.24 (CMe3), 27.75
(Me3C), 29.36, 36.90, 44.13, 45.39 (Ad), 76.56 (HCꢀC),
96.55 (CꢀCH), 209.80 (ꢀCꢀ); 29Si-NMR l(CDCl3)
−19.22, −19.17, −12.1, −0.1, 7.8. Anal. Calc. for
C28H58OSi5: C, 61.01; H, 10.61. Found: C, 61.06; H,
10.82. For 4b: MS m/z 690 (M+); IR 2954, 2931, 2902,
2854, 2085, 1471, 1249, 1081, 1056, 890, 838, 769, 692
(s, 3H, MeSi), 0.22 (s, 9H, Me3Si), 0.23 (s, 9H, Me3Si),
0.24 (s, 9H, Me3Si), 0.97 (s, 9H, t-Bu), 1.64–2.04 (m,
15H, Ad), 7.05 (s, 1H, HCꢀC); 13C-NMR l(CDCl3)
−3.56, −1.61 (MeSi), 1.37, 1.78, 3.50 (Me3Si), 18.34
(CMe3), 27.84 (Me3C), 29.14, 36.75, 39.27, 39.63 (Ad),
98.99 (CO), 153.03, 176.38 (olefinic carbons); 29Si-
NMR l(CDCl3) −18.2, −13.6, −10.6, −7.6, 5.4.
Anal. Calc. for C28H58OSi5: C, 61.01; H, 10.61. Found:
C, 61.01; H, 10.60%.
1
cm−1; H-NMR l(CDCl3) 0.09 (s, 3H, MeSi), 0.098 (s,
3.1.3. Thermolysis of 1a with
3H, MeSi), 0.101 (s, 3H, MeSi), 0.12 (s, 9H, Me3Si),
0.18 (s, 9H, Me3Si), 0.19 (s, 9H, Me3Si), 0.22 (s, 3H,
MeSi), 0.95 (s, 9H, t-Bu), 1.55–1.95 (m, 15H, Ad), 4.75
(s, 1H, HCO), 5.81 (s, 1H, HCꢀC); 13C-NMR l(CDCl3)
−4.64 (Me2PhSi), −2.32 (MePhSi), −0.63 (Me3Si),
−0.43 (Me3Si), −0.27 (MePhSi), 1.31 (Me3Si), 16.54,
18.91 (CMe3), 26.09, 28.63 (Me3C), 28.68, 37.21, 38.16,
38.70 (Ad), 85.77 (CO), 110.43, 119.26 (sp carbons),
136.73, 165.66 (olefinic carbons); 29Si-NMR l(CDCl3)
−72.9, −14.0, −13.9, −9.5, −1.9, 14.5. Anal. Calc.
for C36H74OSi6: C, 62.53; H, 10.79. Found: C, 62.83; H,
10.67%.
tert-butyldimethylsilylacetylene at 160°C
A mixture of 0.1539 g (0.506 mmol) of 1a and 0.0840
g (0.600 mmol) of tert-butyldimethylsilylacetylene was
heated in a sealed glass tube at 160°C for 12 h. The
mixture was analyzed by GLC as being 3a (90% yield)
and 4a (6% yield). Products 3a and 4a were isolated by
column chromatography. For 3a: MS m/z 472 (M+);
IR 2956, 2896, 2858, 1882, 1471, 1390, 1361, 1253,
1
1052, 836, 767, 686 cm−1; H-NMR l(CDCl3) 0.08 (s,
9H, Me3Si), 0.13 (s, 9H, Me3Si), 0.14 (s, 9H, Me3Si),
0.18 (s, 3H, MeSi), 0.20 (s, 3H, MeSi), 0.94 (s, 9H,
t-Bu), 1.12 (s, 9H, t-Bu), 4.54 (s, 1H, HCꢀC); 13C-
NMR l(CDCl3) −2.49, −2.05 (MeSi), −1.17, −1.14,
2.25 (Me3Si), 19.26 (CMe3), 27.70 (Me3C), 32.12
(Me3C), 33.88 (CMe3), 76.54 (HCꢀC), 95.70 (CꢀCH),
209.20(ꢀCꢀ);29Si-NMRl(CDCl3) −19.2, −18.8, −12.1,
0.3, 7.8; exact mass calc. for C22H52OSi5 ([M+])
472.2865, found 472.2880. For 4a: MS m/z 612 (M+);
IR 2954, 2929, 2894, 2858, 2082, 1390, 1361, 1249,
3.1.5. Thermolysis of 2a at 160°C
Compound 2a (0.1009 g, 0.214 mmol) was heated in
a sealed glass tube at 160°C for 12 h. The reaction
mixture was analyzed by GLC as being 3a (96%). All
spectral data obtained for 3a were identical with those
of an authentic sample obtained from the above
reaction.
1066, 894, 836, 773, 694 cm−1 1H-NMR l(CDCl3)
;

A. Naka, M. Ishikawa / Journal of Organometallic Chemistry 611 (2000) 248–255
253
3.1.6. Thermolysis of 2-tert-butyl-2-(trimethylsiloxy)-
1,1,3-tris(trimethylsilyl)-1-silacyclobut-3-ene at 160°C
2-tert-Butyl-2-(trimethylsiloxy)-1,1,3-tris(trimethyl-
silyl)-1-silacyclobut-3-ene (0.1950 g, 0.453 mmol) was
heated in a sealed glass tube at 160°C for 12 h. The
resulting reaction mixture was analyzed by 1H- and
13C-NMR spectrometry. The results indicated that the
starting silacyclobutene was transformed completely
into a propadiene derivative in quantitative yield. All
spectral data for the product were identical with those
of the authentic sample reported previously [13].
84.38 (CO), 111.87, 118.57 (sp carbons), 127.42, 127.73,
128.34, 129.30, 133.72, 134.14, 139.92, 137.89, 141.04,
165.12 (phenyl ring and olefinic carbons); 29Si-NMR
l(CDCl3) −72.1, −23.2, −13.9, −10.0, 15.0. Anal.
Calc. for C34H60OSi6: C, 62.50; H, 9.26. Found: C,
62.28; H, 9.41%.
3.1.9. Thermolysis of 1b with
dimethylphenylsilylacetylene at 120°C
A mixture of 0.3083 g (0.750 mmol) of 1b and 0.1283
g (0.800 mmol) of dimethylphenylsilylacetylene was
heated at 120°C for 12 h. The resulting mixture was
analyzed by GLC as being 5b (53% yield) and 6b (13%
yield), along with the starting compound 1b (10%).
Product 5b and 6b were isolated by column chromato-
graphy. For 5b: MS m/z 570 (M+); IR 3068, 2954,
3.1.7. Thermolysis of 2-adamantyl-2-(trimethylsiloxy)-
1,1,3-tris(trimethylsilyl)-1-silacyclobut-3-ene at 160°C
2-Adamantyl-2-(trimethylsiloxy)-1,1,3-tris(trimethyl-
silyl)-1-silacyclobut-3-ene (0.1580 g, 0.311 mmol) was
heated in a sealed glass tube at 160°C for 12 h. The
2904, 2850, 1452, 1249, 1083, 894, 836, 732, 701 cm−1
;
1
mixture was analyzed by H- and 13C-NMR spectrome-
1H-NMR l(CDCl3) 0.34 (s, 9H, Me3Si), 0.37 (s, 9H,
Me3Si), 0.38 (s, 9H, Me3Si), 0.50 (s, 3H, MePhSi), 0.67
(s, 3H, MePhSi), 1.55–2.03 (m, 15H, Ad), 7.20 (s, 1H,
HCꢀC), 7.22–7.29 (m, 3H, phenyl ring protons), 7.63–
7.65 (m, 2H, phenyl ring protons); 13C-NMR l(CDCl3)
−2.10, 0.24 (MePhSi), 1.44, 1.75, 3.56 (Me3Si), 29.41,
36.87, 39.59, 40.04 (Ad), 97.62 (CO), 127.80, 128.94,
134.52, 139.56 (phenyl ring carbons), 153.35, 175.45
(olefinic carbons); 29Si-NMR l(CDCl3) −18.8, −18.6,
−13.3, −10.3, 6.4; exact mass calc. for C30H54OSi5
([M+]) 570.3021, found 570.3013. For 6b: MS m/z 730
(M+); IR 2954, 2904, 2848, 2086, 1249, 1051, 836, 773,
try, indicating that the starting silacyclobutene was
transformed into a propadiene derivative in quantita-
tive yield. All spectral data for the product were identi-
cal with those of the authentic sample [13].
3.1.8. Thermolysis of 1a with
dimethylphenylsilylacetylene at 120°C
A mixture of 0.2068 g (0.621 mmol) of 1a and 0.1207
g (0.753 mmol) of dimethylphenylsilylacetylene was
heated at 120°C for 12 h. The mixture was analyzed by
GLC as being 5a (52% yield) and 6a (20% yield), along
with the starting compound 1a (5%). Products 5a and
6a were isolated by column chromatography. For 5a:
MS m/z 492 (M+); IR 2958, 2898, 1411, 1363, 1253,
698 cm−1 1H-NMR l(CDCl3) 0.12 (s, 9H, Me3Si),
;
0.13 (s, 9H, Me3Si), 0.17 (s, 9H, Me3Si), 0.38 (s, 3H,
MePhSi), 0.41 (s, 6H, Me2PhSi), 0.51 (s, 3H, MePhSi),
1.47–1.87 (m, 15H, Ad), 4.83 (br s, 1H, HCO), 5.81 (br
s, 1H, HCꢀC), 7.29–7.37 (m, 6H, phenyl ring protons),
7.54–7.65 (m, 4H, phenyl ring protons); 13C-NMR
l(CDCl3) −0.80 (2C) (Me3Si, Me2PhSi), −0.49
(Me3Si), 0.33 (MePhSi), 1.14 (Me3Si), 1.83 (MePhSi),
28.56, 37.14, 38.18, 38.75 (Ad), 84.94 (CO), 111.94,
118.68 (sp carbons), 127.37, 127.74, 128.33, 129.32,
133.71, 134.23, 136.88, 137.66, 141.04, 164.58 (phenyl
ring and olefinic carbons); 29Si-NMR l(CDCl3) −72.1,
−23.2, −14.0, −13.9, −10.2, 15.0. Anal. Calc. for
C40H66OSi6: C, 65.68; H, 9.09. Found: C, 65.32; H,
9.31%.
1
1060, 840, 755, 700 cm−1; H-NMR l(CDCl3) 0.03 (s,
9H, Me3Si), 0.038 (s, 9H, Me3Si), 0.039 (s, 9H, Me3Si),
0.21 (s, 3H, MePhSi), 0.33 (s, 3H, MePhSi), 0.77 (s, 9H,
t-Bu), 6.93 (s, 1H, HCꢀC), 7.16–7.17 (m, 3H, phenyl
ring protons), 7.38–7.40 (m, 2H, phenyl ring protons);
13C-NMR l(CDCl3) −1.98, −0.09 (Me2PhSi), 1.00,
1.19, 3.00 (Me3Si), 29.37 (Me3C), 37.86 (CMe3), 95.28
(CO), 127.44, 128.53, 134.11, 139.42 (phenyl ring car-
bons), 153.37, 175.68 (olefinic carbons); 29Si-NMR
l(CDCl3) −19.1, −18.7, −13.4, −9.4, 6.25; exact
mass calc. for C24H48OSi5 ([M+]) 492.2552, found
492.2566. For 6a: MS m/z 652 (M+); IR 3018, 2954,
2898, 2088, 1427, 1359, 1249, 1216, 1110, 1066, 894,
1
836, 817, 759 cm−1; H-NMR l(CDCl3) 0.13 (s, 18H,
3.1.10. Thermolysis of 1a with triphenylsilylacetylene at
120°C
Me3Si), 0.16 (s, 9H, Me3Si), 0.39 (s, 3H, MePhSi), 0.41
(s, 3H, MePhSi), 0.42 (s, 3H, MePhSi), 0.52 (s, 3H,
MePhSi), 0.89 (s, 9H, t-Bu), 5.01 (d, 1H, HCO, Jꢀ0.6
Hz), 5.83 (d, 1H, HCꢀC, Jꢀ0.6 Hz), 7.29–7.39 (m, 6H
phenyl ring protons), 7.54–7.75 (m, 2H phenyl ring
protons), 7.63–7.65 (m, 2H, phenyl ring protons); 13C-
NMR l(CDCl3) −0.91 (MePhSi), −0.81 (MePhSi),
−0.82 (Me3Si), −0.45 (Me3Si), 0.41 (MePhSi), 1.10
(Me3Si), 1.96 (MePhSi), 27.17 (Me3C), 36.59 (CMe3),
A mixture of 0.1230 g (0.370 mmol) of 1a and 0.1165
g (0.410 mmol) of triphenylsilylacetylene was heated at
120°C for 12 h. Products 7a (0.0923 g, 40% yield), 8a
(0.0298 g, 9% yield) and the starting compound 1a
(0.0498 g, 41%) were isolated by column chromatogra-
phy. For 7a: MS m/z 616 (M+); IR 3072, 3048, 2954,
2923, 2898, 1427, 1245, 1205, 1078, 836 cm−1 1H-
;

254
A. Naka, M. Ishikawa / Journal of Organometallic Chemistry 611 (2000) 248–255
NMR l(CDCl3) 0.14 (s, 9H, Me3Si), 0.23 (s, 9H,
Me3Si), 0.24 (s, 9H, Me3Si), 0.95 (s, 9H, t-Bu), 7.34 (s,
1H, HCꢀC), 7.33–7.41 (m, 9H, phenyl ring protons),
7.63–7.65 (m, 6H, phenyl ring protons); 13C-NMR
l(CDCl3) 1.19, 1.32, 2.93 (Me3Si), 29.68 (Me3C), 31.77
(CMe3), 96.46 (CO), 127.34, 129.02, 135.44, 136.86
(phenyl ring carbons), 158.91, 171.56 (olefinic carbons);
29Si-NMR l(CDCl3) −23.0, −18.0, −13.3, −9.4,
6.6. Anal. Calc. for C34H52OSi5: C, 66.16; H, 8.49.
Found: C, 66.04; H, 8.60. For 8a: MS m/z 900 (M+);
IR 3068, 3050, 2954, 2871, 2084, 1429, 1245, 1112,
3.1.12. Thermolysis of 1a with
dimethylphenylsilylacetylene at 160°C
A mixture of 0.5148 g (1.55 mmol) of 1a and 0.2970
g (1.85 mmol) of dimethylphenylsilylacetylene was
heated at 160°C for 12 h. The mixture was analyzed by
GLC as being 9a (74% yield), along with 6a (11%
yield). Products 6a and 9a were isolated by column
chromatography. For 9a: MS m/z 492 (M+); IR 3070,
2958, 2900, 1887, 1693, 1429, 1253, 1064, 840, 755
1
cm−1; H-NMR l(CDCl3) 0.13 (s, 9H, Me3Si), 0.17 (s,
9H, Me3Si), 0.18 (s, 9H, Me3Si), 0.41 (s, 3H, MePhSi),
0.52 (s, 3H, MePhSi), 1.03 (s, 9H, t-Bu), 4.76 (s, 1H,
HCꢀC), 7.34–7.36 (m, 3H, phenyl ring protons), 7.60–
7.62 (m, 2H, phenyl ring protons); 13C-NMR l(CDCl3)
−1.28 (Me3Si), −1.26 (Me3Si), −0.27 (MePhSi), 0.40
(MePhSi), 2.25 (Me3Si), 31.97 (Me3C), 34.27 (CMe3),
76.12 (HCꢀC), 96.27 (CꢀCH), 127.58, 128.67, 134.03,
140.38 (phenyl ring carbons), 208.54 (ꢀCꢀ); 29Si-NMR
l(CDCl3) −19.1, −18.8, −11.7, 7.9; exact mass calc.
for C24H48OSi5 ([M+]) 492.2552, found 492.2565. All
spectral data for 6a were identical with those of an
authentic sample obtained from the above reaction.
1
1105, 1068, 1027, 887, 836, 781, 738, 698 cm−1; H-
NMR l(CDCl3) −0.12 (s, 9H, Me3Si), 0.20 (s, 9H,
Me3Si), 0.31 (s, 9H, Me3Si), 0.77 (s, 9H, t-Bu), 5.11 (s,
1H, HCO), 6.07 (s, 1H, HCꢀC), 7.34–7.76 (m, 15H
phenyl ring protons); 13C-NMR l(CDCl3) −0.59
(Me3Si), −0.22 (Me3Si), 0.95 (Me3Si), 27.82 (Me3C),
36.85 (CMe3), 84.78 (CO), 115.59, 115.72 (sp carbons),
127.17, 127.85, 128.87, 129.85, 133.35, 135.64, 136.64,
137.07, 141.13, 162.35 (phenyl ring and olefinic car-
bons); 29Si-NMR l(CDCl3) −71.3, −30.3, −12.8,
−12.5, −11.9, 15.8. Anal. Calc. for C54H68OSi6: C,
71.93; H, 7.60. Found: C, 72.01; H, 7.63%.
3.1.13. Thermolysis of 1b with
dimethylphenylsilylacetylene at 160°C
3.1.11. Thermolysis of 1b with triphenylsilylacetylene at
120°C
A mixture of 0.5104 g (1.24 mmol) of 1b and 0.2001
g (1.25 mmol) of dimethylphenylsilylacetylene was
heated at 160°C for 12 h. The mixture was analyzed by
GLC as being 9b (72% yield), along with 6b (11%
yield). Products 6b and 9b were isolated by column
chromatography. For 9b: MS m/z 570 (M+); IR 2964,
A mixture of 0.1201 g (0.293 mmol) of 1b and 0.1346
g (0.474 mmol) of triphenylsilylacetylene was heated at
120°C for 12 h. Product 7b (0.0858 g, 42% yield), 8b
(0.0260 g, 9% yield) and the starting compound 1b
(0.0581 g, 48%) were isolated by column chromatogra-
phy. For 7b: MS m/z 694 (M+); IR 3068, 3050, 2904,
2848, 1429, 1251, 1105, 1014, 908, 890, 836, 736, 703
2906, 2850, 1891, 1685, 1251, 1064, 840, 754, 700 cm−1
;
1H-NMR l(CDCl3) 0.11 (s, 9H, Me3Si), 0.14 (s, 9H,
Me3Si), 0.16 (s, 9H, Me3Si), 0.42 (s, 3H, MePhSi), 0.49
(s, 3H, MePhSi), 1.59–1.93 (m, 15H, Ad), 4.74 (s, 1H,
HCꢀC), 7.32–7.37 (m, 3H, phenyl ring protons), 7.55–
7.58 (m, 2H, phenyl ring protons); 13C-NMR l(CDCl3)
−1.29 (Me3Si), −1.27 (Me3Si), −0.01 (MePhSi), 0.56
(MePhSi), 2.26 (Me3Si), 29.16, 36.76, 43.89, 51.94 (Ad),
76.23 (HCꢀC), 96.95 (CꢀCH), 127.51, 128.59, 134.03,
140.67 (phenyl ring carbons), 209.00 (ꢀCꢀ); 29Si-NMR
l(CDCl3) −19.2, −19.1, −12.1, −11.7, 7.9; exact
mass calc. for C30H54OSi5 ([M+]) 570.3021, found
570.2999. All spectral data for 6b were identical with
those of an authentic sample obtained from the above
reaction.
1
cm−1; H-NMR l(CDCl3) 0.11 (s, 9H, Me3Si), 0.19 (s,
9H, Me3Si), 0.21 (s, 9H, Me3Si), 1.40–1.78 (m, 15H,
Ad), 7.25 (s, 1H, HCꢀC), 7.27–7.37 (m, 9H, phenyl
ring protons), 7.58–7.62 (m, 6H, phenyl ring protons);
13C-NMR l(CDCl3) 1.37, 1.72, 3.37 (Me3Si), 28.88,
36.35, 39.12, 39.90 (Ad), 98.61 (CO), 127.34, 128.97,
135.51, 136.96 (phenyl ring carbons), 159.26, 170.18
(olefinic carbons); 29Si-NMR l(CDCl3) −22.1, −17.6,
−13.3, −10.2, 6.4. Anal. Calc. for C40H58OSi5: C,
69.10; H, 8.41. Found: C, 69.00; H, 8.46. For 8b: MS
m/z 978 (M+); IR 3068, 3048, 2904, 2848, 2082, 1429,
1
1247, 1105, 1081, 1052, 838, 781, 736, 700 cm−1; H-
NMR l(CDCl3) −0.14 (s, 9H, Me3Si), 0.22 (s, 9H,
Me3Si), 0.28 (s, 9H, Me3Si), 1.31–1.97 (m, 15H, Ad),
4.89 (br s, 1H, HCO), 6.08 (br s, 1H, HCꢀC), 7.33–7.74
(m, 30H, phenyl ring protons); 13C-NMR l(CDCl3)
−0.61, −0.24, 0.95 (Me3Si), 28.48, 36.95, 38.51, 39.20
(Ad), 85.25 (CO), 115.59, 115.72 (sp carbons), 127.14,
127.83, 128.81, 129.85, 133.33, 135.63, 136.64, 137.10,
141.13, 161.65 (phenyl ring and olefinic carbons); 29Si-
NMR l(CDCl3) −71.2, −13.0, −12.5, −12.1, 15.8.
Anal. Calc. for C60H74OSi6: C, 73.55; H, 7.61. Found:
C, 73.50; H, 7.68%.
3.1.14. Thermolysis of 1a with triphenylacetylene at
160°C
A mixture of 0.1631 g (0.491 mmol) of 1a and 0.1745
g (0.614 mmol) of triphenylsilylacetylene was heated at
160°C for 12 h. Products 8a (0.1330 g, 30% yield) and
10a (0.1750 g, 58% yield) were isolated by column
chromatography. For 10a: MS m/z 616 (M+); IR 3070,
3050, 2958, 2898, 1886, 1429, 1253, 1043, 842, 700
1
cm−1; H-NMR l(CDCl3) −0.18 (s, 9H, Me3Si), 0.10
(s, 9H, Me3Si), 0.16 (s, 9H, Me3Si), 1.04 (s, 9H, t-Bu),

A. Naka, M. Ishikawa / Journal of Organometallic Chemistry 611 (2000) 248–255
255
4.56 (s, 1H, HCꢀC), 7.32–7.38 (m, 9H, phenyl ring
protons), 7.69–7.73 (m, 6H, phenyl ring protons); 13C-
NMR l(CDCl3) −1.58, −1.29, 2.38 (Me3Si), 31.77
(Me3C), 34.44 (CMe3), 77.97 (HCꢀC), 93.57 (CꢀCH),
127.52, 129.08, 135.73, 136.61 (phenyl ring carbons),
210.78 (ꢀCꢀ); 29Si-NMR l(CDCl3) −19.2, −18.9,
−16.1, −11.3, 8.4. Anal. Calc. for C34H52OSi5: C,
66.16; H, 8.49. Found: C, 66.09; H, 8.50%. All spectral
data for 8a were identical with those of an authentic
sample obtained from the above reaction.
Inter-element Linkage’ (No. 11120260) from Ministry
of Education, Science, Sports and Culture of Japan and
by Research for the Future Program (JSPS-
PFTF96P00206), to which our thanks are due. We also
express our appreciation to Sumitomo Electric Indus-
try, and Tokuyama for financial support.
References
[1] A.G. Brook, J. Organomet. Chem. 300 (1986) 21.
[2] (a) A.G. Brook, in: S. Patai, Z. Rappoport (Eds.), The Chem-
istry of Organic Silicon Compounds; Part 2, Wiley, New York,
1989, Chapter 15. (b) A.G. Brook, M.A. Brook, Adv.
Organomet. Chem. 39 (1996) 71.
[3] P. Lassacher, A.G. Brook, A.J. Lough, Organometallics 14
(1995) 4359.
[4] J. Ohshita, Y. Masaoka, M. Ishikawa, Organometallics 10 (1991)
3775.
[5] A.G. Brook, P. Chui, J. McClenaghan, A.J. Lough,
Organometallics 10 (1991) 3292.
[6] D. Bravo-Zhivotovskii, V. Braude, A. Stanger, M. Kapon, Y.
Apeloig, Organometallics 11 (1992) 2326.
[7] J. Ohshita, Y. Masaoka, M. Ishikawa, Organometallics 12 (1993)
876.
[8] A.G. Brook, J.W. Harris, J. Lennon, M. El Sheikh, J. Am.
Chem. Soc. 101 (1979) 83.
[9] J. Ohshita, H. Hasebe, Y. Masaoka, M. Ishikawa, Organometal-
lics 13 (1994) 1064.
[10] M. Ishikawa, S. Matsui, A. Naka, J. Ohshita, J. Main Group
Chem. 1 (1996) 219.
[11] A.G. Brook, A. Ionkin, A.J. Lough, Organometallics 15 (1996)
1275.
[12] M. Ishikawa, S. Matsui, A. Naka, J. Ohshita, Organometallics
15 (1996) 3836.
3.1.15. Thermolysis of 1b with triphenylsilylacetylene at
160°C
A mixture of 0.1100 g (0.268 mmol) of 1b and 0.1240
g (0.437 mmol) of triphenylsilylacetylene was heated at
160°C for 12 h. Products 8b (0.1111 g, 43% yield) and
10b (0.0789 g, 43% yield) were isolated by column
chromatography. For 10b: MS m/z 694 (M+); IR 3070,
3048, 2954, 2904, 2848, 1891, 1429, 1251, 1106, 1045,
1
842, 738, 700 cm−1; H-NMR l(CDCl3) −0.20 (s, 9H,
Me3Si), 0.09 (s, 9H, Me3Si), 0.16 (s, 9H, Me3Si), 1.42–
1.81 (m, 15H, Ad), 4.54 (s, 1H, HCꢀC), 7.29–7.39 (m,
9H, phenyl ring protons), 7.66–7.71 (m, 6H, phenyl
ring protons); 13C-NMR l(CDCl3) −1.60 (Me3Si),
−1.30 (Me3Si), 2.42 (Me3Si), 29.19, 36.53, 36.66, 43.51
(Ad), 78.04 (HCꢀC), 94.17 (CꢀCH), 127.46, 129.05,
135.91, 136.67 (phenyl ring carbons), 211.17 (ꢀCꢀ);
29Si-NMR l(CDCl3) −19.3, −19.2, −16.4, −11.4,
8.35. Anal. Calc. for C40H58OSi5: C, 69.10; H, 8.41.
Found: C, 69.10; H, 8.42%. All spectral data for 8b
were identical with those of an authentic sample ob-
tained from the above reaction.
[13] A. Naka, M. Ishikawa, S. Matsui, J. Ohshita, A. Kunai,
Organometallics 15 (1996) 5759.
[14] A.G. Brook, A. Baumegger, A.J. Lough, Organometallics 11
(1992) 3088.
Acknowledgements
[15] A.G. Brook, S.C. Nyburg, F. Abdesaken, B. Gutekunst, G.
Gutekunst, R. Krishna, M.R. Kallury, Y.C. Poon, Y.-M. Chan,
W. Wong-Ng, J. Am. Chem. Soc. 104 (1980) 5667.
This work was supported by Grant-in-Aid for Scien-
tific Research on Priority Areas ‘The Chemistry of
.