Iodochlorination of Silyl- and Germylphenylacetylenes

Article abstract of DOI:10.1002/hc.20001

Reactions of Si- and Ge-substituted alkynes with KICl₂ were investigated. (1-Germatranyl)-phenylacetylenes and (triphenylsilyl) phenylacetylene gave Z-iodochloroalkenes with chlorine and phenyl groups attached to the same carbon atom. Adduct st

Full text of DOI:10.1002/hc.20001

Heteroatom Chemistry
Volume 15, Number 2, 2004
Iodochlorination of Silyl- and
Germylphenylacetylenes
Anastasia A. Selina,1 Anna E. Zhachkina,1 Sergey S. Karlov,1
Andrei V. Churakov,2 and Galina S. Zaitseva1
1Chemistry Department, Moscow State University, Moscow, Russia
2Institute of General and Inorganic Chemistry, Russian Academy of Science, Moscow, Russia
Received 16 November 2003; accepted 15 December 2003
“atrane” moiety possessing specific steric and elec-
ABSTRACT: Reactions of Si- and Ge-substituted al-
tronic properties may influence stability, reactivity,
kynes with KICl2 were investigated. (1-Germatranyl)-
and ability to undergo chemical transformations.
phenylacetylenes and (triphenylsilyl)phenylacetylene
Recently we have studied the reactions of ele-
gave Z-iodochloroalkenes with chlorine and phenyl
ment substituted acetylenes with different bromi-
groups attached to the same carbon atom. Adduct
nation reagents [5–7]. In general, the treatment of
structures were confirmed by X-ray diffraction studies.
N(CH2CHRO)3GeC CPh (R = H, 1; Me, 2) with
ꢀ
C
2004 Wiley Periodicals, Inc. Heteroatom Chem 15:169–
NBS/DMSO led to N(CH2CHRO)3GeC(Br2)C(O)Ph.
The reactions of 1 and 2 with bromine or TBAT
(tetra-n-butylammonium tribromide) gave only Z-
174, 2004; Published online in Wiley InterScience
(www.interscience.wiley.com). DOI 10.1002/hc.20001
dibromo adducts. The treatment of Ph3SiC CPh
(3) with bromine also led to Z-isomer. In contrast,
INTRODUCTION
Si C bond in N(CH2CH2O)3SiC CPh (4) was bro-
ken by Br2 [7]. The bromination of trialkylsily-
lacetylenes with bromine led to mixtures of Z- and E-
dibromoadducts, Z-isomers were the major products
[6,7]. The opposite ratio of Z/E-isomers were found
for reaction of Alk3SiC CPh with TBAT [7]. In con-
tinuation of our studies of triple bond addition reac-
tions here we report the reactions of germatranyl-
(1, 2) and silatranyl-(4) phenylacetylenes as well
as their tetracoordinated counterparts, Ph3SiC CPh
(3) and Me3SiC CPh (5) with KICl2 leading to
iodochloroadducts.
Metallatranes, N(CH2CHRO)3M X, are the most sys-
tematically studied compounds of Main group ele-
ments with nonclassical coordination number [1].
Those of the group 14 elements have been investi-
gated in detail [2–3]. The main focus is the nature of
transannular interaction M ← N and the influence of
apical substituent X on strength of this interaction.
Biological activity of these compounds is of great in-
terest as well [2,4]. At the same time the reactivity
of metallatranes (M = Si, Ge) has been studied to a
very limited extent especially the transformations of
apical substituent X. However, it is obvious that the
RESULTS AND DISCUSSION
The reactions of germatranes 1 and 2, as well as
(triphenylsilyl)phenylacetylene (3) with KICl2 are
regio- and stereospecific and lead to corresponding
Z-isomers 6–8 (Scheme 1). The structures of adducts
6–8 were confirmed by X-ray diffractometry.
Correspondence to: Sergey S. Karlov; e-mail: sergej@org.chem.
msu.su.
Contract grant sponsor: Russian Foundation for Basic
Research.
Contract grant number: 01-03-32474.
c
ꢀ
2004 Wiley Periodicals, Inc.
169

170 Selina et al.
KICl /CHCl
2
3
Me3Si C C Ph −−−−−−−→
5
→ Z,E-Me3Si C(I) C(Cl) Ph
11
SCHEME 3
The structures of iodochloroalkenes were con-
firmed by elemental analyses, 1H and 13C NMR spec-
troscopy, mass-spectrometry as well as X-ray crys-
tallography (for 6–8). To the best of our knowledge,
the only one crystal structure of iodochloroalkene,
(cis-C6H5SO2C(I) C(Cl)H), was reported [9]. The
molecular structures of 6, 7, and 8 are shown in
Figs. 1–3. Carbon-carbon double bond lengths in
SCHEME 1
On the contrary, treatment of silatranylpheny-
lacetylene 4 with KICl2 gave silatrane 9 as a major
product. However, NMR data testify the presence of
Z-adduct 10 in reaction mixture (Scheme 2).
˚
6–8 (1.312(7)–1.34(1) A) are close to those previ-
ously found in corresponding dibromides (1.27(1)–
Iodochlorination of (trimethylsilyl)phenylace-
tylene 5 led to iodochloroalkene 11 (Z/E = 6/1)
(Scheme 3). The Z/E signal assignment and ratio has
˚
1.31(1) A) [5,7]. The coordination polyhedron of the
germanium atom in germatranes Z–6 and Z–7 rep-
resents a distorted trigonal bipyramid with N and C
atoms in the apical positions and the three oxygen
atoms in equatorial sites. The germanium atom is
been determined by comparison of 1H NMR and 13
C
NMR spectroscopy data for compound 11 with those
previously found for corresponding dibromoalkene
[7].
Iodochloroalkenes synthesized may serve as use-
ful intermediates for further organic transforma-
tions mainly due to the presence of reactive carbon-
iodine bond in the molecules.
The exclusive formation of Z-dihaloalkenes 6–8
in iodochlorination reactions of acetylenes 1–3
might be attributed to the possible steric hin-
drances derived from the presence of bulky groups
at triple bond. Similar cis-stereospecific addition of
bromine to triple bond was previously found for tert-
BuC CPh [8]. Steric crowding is probably less in
the case of silane 5 when E-adduct also formed to-
gether with Z-iodochloride. Silatrane 4 should be
noted apart, since the main course of its reaction
with KICl2 is the cleavage of the Si C bond. It may
occur either as a result of the halogen attack on Si C
bond or owing to addition of halogen to triple bond
followed by β-elimination.
˚
displaced by 0.23–0.24 A towards the phenylethenyl
substituent from the equatorial plane defined by the
three oxygen atoms. The N Ge C fragment is almost
linear (176.9(2)◦ and 177.4(3)◦) in both molecules.
The N Ge distances in compound 6 and 7 lie within
the typical range for germatranes (2.160(2)–2.32(1)
˚
A) [10,11] and clearly verify the existence of N Ge
transannular bond in these compounds. No short
intermolecular contacts were observed in the struc-
tures of 6–8.
EXPERIMENTAL
General Comments
1–5 were prepared as described earlier [7]. All sol-
vents were dried by standard procedures and dis-
tilled before use. NMR spectra were recorded at 25◦C
on Bruker AC 300 and Varian VXR 400 spectrome-
ters; CDCl3 was used as the solvent and for internal
1
deuterium lock. The chemical shifts in the H and
13C NMR spectra are given in ppm relative to internal
TMS. The IR spectra were recorded on Zeiss UR-20.
Elemental analyses were carried out by the Microan-
alytical Laboratory of the Chemistry Department of
the Moscow State University. Mass spectra (EIMS)
were obtained on a VARIAN CH-7a device using
electron impact ionization at 70 eV; all assignments
were made with reference to the most abundant
isotopes.
SCHEME 2

Iodochlorination of Silyl- and Germylphenylacetylenes 171
FIGURE 1 Molecular structure of 6. Minor components of disordered groups are shown using open lines. Displacement ellip-
◦
˚
soids are shown at 50% probability level. Hydrogen atoms are omitted for clarity. Selected bond lengths (A) and angles ( ): N Ge
2.213(5), Ge C(8) 1.960(5), C(7) C(8) 1.325(7), C(8) I(1) 2.075(5), C(7) Cl 1.753(6), N Ge C(8) 176.9(2), Ge C(8) I(1)
115.2(3), Ge C(8) C(7) 126.0(4), I(1) C(8) C(7) 118.7(4), C(8) C(7) Cl 123.1(5), C(1) C(7) C(8) 125.2(5).
FIGURE 2 Molecular structure of 7. Minor components of disordered groups are shown using open lines. Displacement
˚
ellipsoids are shown at 50% probability level. Hydrogen atoms are omitted for clarity. Selected bond lengths (A) and angles
(◦): N Ge 2.216(8), Ge C(1) 1.980(9), C(1) C(2) 1.34(1), C(1) I 2.047(9), C(2) Cl 1.76(1), N Ge C(1) 177.4(3), Ge–C(1)–I
115.5(4), Ge–C(1)–C(2) 124.4(7), I C(1) C(2) 120.1(7), C(1) C(2) Cl 122.0(8), C(1) C(2) (3)C 125.5(9).

172 Selina et al.
2: Recrystallization of solid residue from
CHCl3/n-hexane yielded Z-2-chloro-1-[1-(3,7,10-tri-
methyl)germatranyl]-1-iodo-2-phenylethene (7)
(69%). Calcd. for C17H23ClGeINO3 (524.230): C,
38.95; H, 4.42; N, 2.67. Found (%): C, 38.78; H,
4.29; N, 2.88. IR (Nujol): ꢀ(C C) 1575 cm−1. 1H
NMR (CDCl3) δ = 0.92–3.92 (18H, ABXM3 system of
NCH2CHMeO group protons); 7.19–7.23, 7.49–7.53
(2m, 5H, C6H5). 13C NMR (CDCl3) δ = 19.98, 20.17,
20.45, 22.79 (CH3); 59.64, 62.19, 62.54, 62.81, 63.65,
64.06, 65.61, 65.68 (NCH2CHO); 101.81 (IC );
128.36, 128.39, 129.28, 140.39 (C6H5); 145.94 (ClC )
(other six signals of double bond and aromatic car-
bons were not found due to the small concentration);
two diastereomers.
3: Recrystallization of solid residue from
toluene yielded Z-2-chloro-1-iodo-2-phenyl-1-(tri-
phenylsilyl)ethene (8) (86%), m.p. 135.0–135.5◦C.
Calcd. for C26H20ClISi (522.89): C, 59.72; H, 3.86;
Si, 5.37. Found (%): C, 59.60; H, 3.77; Si, 5.49.
IR (Nujol): ꢀ(C C) 1576 cm−1. 1H NMR (CDCl3)
δ = 6.70–6.74, 6.83–6.87, 7.00–7.02, 7.20–7.23, 7.27–
7.31, 7.48–7.50 (6m, 20H, 4C6H5). 13C NMR (CDCl3)
δ = 103.38 (IC ); 127.58, 127.68, 136.03, 147.67
(SiC6H5); 128.66, 129.45, 133.58, 138.22 (C6H5C);
151.28 (ClC ). EI MS (70 eV): m/z = 522 (M+, 2%),
445 (M+ − Ph, 1%), 395 (M+ − I, 28%), 359 (M+ − I −
Cl, 17%), 317 (M+ − I − Ph, 95%), 259 (SiPh3+, 92%),
241 (M+ − I − 2Ph, 14%), 217 (Ph2SiCl+, 100%).
FIGURE 3 Molecular structure of 8. Displacement ellipsoids
are shown at 50% probability level. Selected bond lengths
◦
˚
(A) and angles ( ): Si C(1) 1.896(5), C(1) C(2) 1.312(7),
C(2) C(3) 1.473(7), C(1) I 2.106(5), C(2) Cl 1.782(5),
Si C(1) I 109.2(2), Si C(1) C(2) 130.9(4), I C(1) C(2)
119.9(4), C(1) C(2) Cl 122.5(4), C(1) C(2) C(3) 126.5(4),
Cl C(2) C(3) 111.0(4).
1
4: H NMR spectrum of solid residue washed
with n-hexane has shown the presence of start-
ing material 4, 1-chlorosilatrane (9), and Z-adduct
10 (ratio 1:10:1). Recrystallization of solid residue
from CHCl3/n-hexane yielded precipitate with Z-
2-chloro-1-iodo-2-phenyl-1-(1-silatranyl)ethene (10)
Reactions of Studied Phenylacetylenes
with KICl2
Phenylacetylene (1–5) (3.1 mmol) was added to a
solution of KICl2 (6.2 mmol) in 50 ml of CHCl3.
The reaction mixture was stirred for 24 h at room
temperature then washed with 5% aqueous Na2S2O3
(3 × 30 ml) and water (20 ml). Organic layer was
dried over sodium sulfate, and the solvent was re-
moved in vacuo.
1: Recrystallization of solid residue from CHCl3/
n-hexane yielded Z-2-chloro-1-(1-germatranyl)-1-
iodo-2-phenylethene (6) (76%), m.p. 176–178◦C (de-
comp.). Calcd. for C14H17ClGeINO3 (482.150): C,
34.88; H, 3.55; N, 2.91. Found: C, 35.14; H, 3.71; N,
2.93. IR (Nujol): ꢀ(C C) 1572 cm−1. 1H NMR (CDCl3)
δ = 2.69 (t, 6H, NCH2); 3.52 (t, 6H, OCH2); 7.24–
7.30, 7.48–7.52 (2m, 5H, C6H5). 13C NMR (CDCl3)
δ = 52.50 (NCH2); 56.95 (OCH2); 99.96 (IC ); 127.16,
128.26, 128.82, 141.51 (C6H5); 146.89 (ClC ). EI MS
(70 eV): m/z = 483 (M+, 4%), 356 (M+ − I, 72%),
220 (M+ − C8H5ClI, 100%), 190 (M+ − C8H5ClI −
CH2O, 36%), 160 (M+ − C8H5ClI − 2CH2O, 47%),
146 (M+ − C8H5ClI − CH2O − CH2CH2O, 41%), 130
(M+ − C8H5ClI − 3CH2O, 7%).
1
as major component. H NMR (CDCl3) δ = 2.70 (t,
6H, NCH2); 3.54 (t, 6H, OCH2); 7.19–7.26, 7.40–7.43
(2m, 5H, C6H5). 13C NMR (CDCl3) δ = 51.60 (NCH2);
57.59 (OCH2); 101.65 (IC ); 128.49, 128.56, 129.40,
139.57 (C6H5); 146.97 (ClC ). The 13C NMR spec-
trum of filtrate indicated the presence of IC CC6H5:
13C NMR (CDCl3) δ = 6.05 (IC ); 94.11 ( CC6H5);
123.37, 128.21, 128.77, 132.30 (C6H5).
5: Fractionation of the liquid residue gave Z,E-2-
chloro-1-iodo-2-phenyl-1-(trimethylsilyl)ethene (11)
(90%), b.p. 170–176◦C (4 Torr). Calcd. for C11H14ClISi
(336.67): C, 39.24; H, 4.19; Si, 8.34. Found (%): C,
39.87; H, 4.25; Si, 8.49. IR (Nujol): ꢀ(C C) 1576
1
cm−1. H NMR (CDCl3) δ = −0.06 (s, 9H, SiMe3, Z-
isomer); 0.39 (s, 9H, SiMe3, E-isomer); 7.29–7.38 (m,
5H, C6H5). Z/E ratio = 18/1. 13C NMR (CDCl3) δ =
−0.04 (SiMe3, Z-isomer), 0.91 (SiMe3, E-isomer);
109.38 (IC ); 128.24, 128.28, 128.63, 139.68 (C6H5,
Z-isomer); 129.22, 129.36, 129.42, 138.57 (C6H5,
E-isomer); 145.76 (ClC ); signals of double bond

Iodochlorination of Silyl- and Germylphenylacetylenes 173
TABLE 1 Crystal Data, Data Collection and Refinement Parameters for Compounds 6, 7, and 8
6
7
8
Empirical formula
Formula weight
Colour, habit
Crystal size (mm)
Crystal system
Space group
C14H17ClGeINO3
482.23
yellow block
0.2 × 0.2 × 0.2
monoclinic
P21/n
C17H23ClGeINO3
524.30
yellow block
0.5 × 0.2 × 0.1
monoclinic
P21/n
C26H20ClISi
522.86
pink block
0.3 × 0.2 × 0.1
triclinic
P-1
Unit cell dimensions:
˚
a/A
9.371(3)
10.096(2)
8.318(4)
14.414(8)
10.433(2)
10.551(3)
˚
b/A
˚
c/A
17.220(5)
90
95.93(2)
90
1620.5(8)
4
1.977
16.783(5)
90
93.02(3)
90
2009(2)
4
1.733
10.739(3)
88.59(2)
83.53(2)
74.73(2)
1133.1(5)
2
α/◦◦
β/◦
γ/
3
˚
Volume (A )
Z
Dcalc (g cm−3
)
1.532
1.594
520
Enraf-Nonius CAD4
293
µ (mm−1
F(000)
)
3.968
3.208
1032
Enraf-Nonius CAD4
293
936
Enraf-Nonius CAD4
293
Diffractometer
Temperature (K)
˚
Radiation (λ/A)
graphite
monochromatized
MoKα (0.71073)
2.34–25.48
−11 ≤ h ≤ 11
0 ≤ k ≤ 12
0 ≤ l ≤ 20
graphite
monochromatized
MoKα (0.71073)
2.43–24.98
−9 ≤ h ≤ 9
−17 ≤ k ≤ 3
−4 ≤ l ≤ 19
5845
graphite
monochromatized
MoKα (0.71073)
2.00–24.97
−12 ≤ h ≤ 8
−12 ≤ k ≤ 12
0 ≤ l ≤ 12
θ range (◦)
Index ranges
Reflections collected
3113
3811
Independent reflections
3011
3527
3630
[Rint = 0.0494]
[Rint = 0.0564]
[Rint = 0.0176]
Data/restraints/params
3011/0/218
3085/0/216
3312/0/342
Goodness-of-fit on F2
R indices [I > 2σ(I )]
R indices (all data)
Extinction coefficient
1.371
1.036
1.059
R1 = 0.0427, wR2 = 0.1100 R1 = 0.0597, wR2 = 0.1482 R1 = 0.0381, wR2 = 0.0890
R1 = 0.0542, wR2 = 0.1133 R1 = 0.1327, wR2 = 0.1831 R1 = 0.0745, wR2 = 0.1019
0.0277(10)
–
–
−3
˚
Largest diff. peak/hole (e A
)
0.894/−0.924
0.909/−1.388
0.807/−0.345
carbons were not found due to the small concentra-
tion of E-11. EI MS (70 eV): m/z = 336 (M+, 4%), 321
(M+ − Me, 4), 209 (M+ − I, 1), 193 (M+ − I − Me, 3),
159 (M+ − I − Cl − Me, 12%), 136 (M+ − I − SiMe3,
7%), 93 (Me2SiCl+, 100%), 73 (SiMe3+, 29%).
As for the structure 8, all hydrogen atoms were lo-
cated from difference Fourier synthesis and refined
isotropically.
Crystallographic data (excluding structure fac-
tors) for the structures reported in this paper
have been deposited with the Cambridge Crystallo-
graphic Data Centre as supplementary publications
no. CCDC-223441 for 6, 223442 for 7, and 223443 for
8. Copies of the data can be obtained free of charge
on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK (fax: C44(1223)336-033; e-mail: de-
posit@ccdc.cam.ac.uk).
X-Ray Crystallography Study of 6–8
Table 1 summarizes the crystal data as well as details
of data collection and structure determination. The
structures were solved by direct methods (SHELX-
86 [12]) and refined by full-matrix least squares on
F2 (SHELXL-97 [13]) with anisotropic displacement
parameters for all non-hydrogen atoms. In the struc-
tures 6 and 7 β-carbon atoms of atrane fragments
were found to be disordered over two positions with
approximately equal occupancies. In the structures
6 and 7 all hydrogen atoms were placed in calcu-
lated positions and refined using a riding model.
ACKNOWLEDGMENTS
We thank Dr. A. V. Yatsenko (MSU) for the X-ray crys-
tal structure determination of 6. We also thank Dr.
S. E. Sosonyuk (MSU) for a gift of KICl2.

174 Selina et al.
Lorberth, J.; Zaitseva, G. S. J. Lorberth, G. S. Het-
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Perkin Trans 1 1978, 1278–1282.
[9] Bel’skii, V. K.; Shainyan, B. A.; Mirskova, A. N. Zh
Strukt Khim 1986, 27, N 2, 188–191. (Russian)
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