(Z)-1-[2-(tribenzylstannyl)vinyl]-1- cyclooctanol: Synthesis, characterization, halodebenzylation, and crystal structure

Article abstract of DOI:10.1081/SIM-120030441

The synthesis and properties of (Z)-1-[2-(tribenzylstannyl)vinyl]-1- cyclooctanol (1) are described. Compound (1) crystallizes from alcohol in the monoclinic space group P2₁/c with unit-cell dimensions a = 9.348(1) A, b = 26.143(1) A, c = 10.70

Full text of DOI:10.1081/SIM-120030441

SYNTHESIS AND REACTIVITY IN INORGANIC AND METAL-ORGANIC CHEMISTRY
Vol. 34, No. 3, pp. 565–572, 2004
(Z)-1-[2-(Tribenzylstannyl)vinyl]-1-
cyclooctanol: Synthesis, Characterization,
Halodebenzylation, and Crystal Structure
3
1
1
Yujie Ren,1,2, Jia Jun, Lihui Yu, Minghua Li,
*
Xuefeng Yang,1 Boshun Wan,2 and Huilin Chen2
1Chemistry Department, Dalian University of Technology,
Dalian, P.R. China
2Dalian Institute of Chemical Physics, The Chinese Academy of Science,
Dalian, P.R. China
3Jilin University, Changchun, P.R. China
ABSTRACT
The synthesis and properties of (Z)-1-[2-(tribenzylstannyl)vinyl]-1-cyclo-
octanol (1) are described. Compound (1) crystallizes from alcohol in the
˚
monoclinic space group P21/c with unit-cell dimensions a ¼ 9.348(1) A,
3
˚
˚
˚
b ¼ 26.143(1) A, c ¼ 10.705(1) A, b ¼ 95.09(1)8, V ¼ 2605.9(1) A ,
Z ¼ 4, Dc ¼ 1.390 g cm23, m ¼ 10 cm21, finalR ¼ 0.033 for 3165 observed
2
2
reflection (jFj ꢀ 8sjFj ). The x-ray diffraction analysis of this compound
shows intramolecular coordination of oxygen to the tin atom giving rise
to a five-membered ring in which the metal exhibits a distorted trigonal
*
Correspondence: Yujie Ren, Chemistry Department, Dalian University of Techno-
logy, Dalian 116024, P.R. China; E-mail: yujie_ren@163.com.
565
DOI: 10.1081/SIM-120030441
0094-5714 (Print); 1532-2440 (Online)
www.dekker.com
Copyright # 2004 by Marcel Dekker, Inc.

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Ren et al.
bipyramidal geometry. Compound (1) by halodebenzylation by Br2 or ICl
forms the corresponding (Z)-1-[2-(dibenzylhalostannyl)vinyl]-1-cyclo-
octanol or (Z)-1-[2-(benzyldi-halostannyl)vinyl]-1-cyclooctanol, respect-
1
ively. All compounds were characterized by elemental analyses, IR, H
NMR.
Key Words: Halodebenzylation; Crystal sturcutre; (Z)-1-[2-(tribenzyl-
stannyl)vinyl]-1-cyclooctanol.
INTRODUCTION
It was recently reported[1–4] that (C6H5CH2)3SnH adds to 1-ethynyl-
cyclo-heptanol to give (Z)-1-[2-(tribenzylstannyl)vinyl]-1-cycloheptanol.
This tribenzylvinyltin derivative reacts with one or two equivalents of halogen
(Br2 or ICl), leading exclusively to the cleavage of one or two benzyl-tin
bonds, respectively. A 1 : 1 molar ratio gives rise to (Z)-1-[2-(dibenzylhalo-
stannyl)-vinyl]-1-cycloheptanol, a 2 : 1 molar ratio, (Z)-1-[2-(benzyldihalo-
stannyl)-vinyl]-1-cycloheptanol, which exhibits interesting results against
P388 lymphocytic leukemia in mice and BEL-7402 liver cancer in humans
(the results will be reported elsewhere).
To enable us to further study this structure/activity relationship, we
synthesized (Z)-1-[2-(tribenzylstannyl)vinyl]-1-cyclooctanol (1) and corres-
ponding mono- and dihalides (2)–(5) as shown in Eqs. (1), (2) and (3).

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(Z)-1-[2-(Tribenzylstannyl)vinyl]-1-cyclooctanol
EXPERIMENTAL
567
Materials
1-Ethynyl-1-cyclooctanol was prepared by the literature method,[5] b.p.
78–80 8C/10 mmHg; yield: 78% and was recrystallized with pentane before
use (m.p. 43–44 8C, lit. 44–44.5 8C). Tribenzyltin hydride was prepared
according to the procedure of Kuivila,[6] m.p. 102–104 8C, yield: 45%,
n(Sn–H): 1835 cm21 (lit. n(Sn–H): 1835 cm21). It was used directly without
separation.
Physical Measurements
A crystal, dimensions 0.24 mm ꢁ 0.32 mm ꢁ 0.38 mm, was used to
collect data on a Rigaku R-AXIS RAPID IP automatic diffractometer.
IR spectra were recorded on a Nicolet Instrument Corporation 360 FT-IR
1
ESP spectrometer, H NMR spectra were obtained on a DRX-400 spec-
trometer in CDCl3 with TMS as internal standard. The data for the content
of C and H were recorded on a PE 2400 C-H-N automatic element analyzer.
The content of Sn was determined on a VRA-20 x-ray fluorescence
spectrometer.
Reaction of 1-Ethynyl-1-cyclooctanol with
Tribenzyltin Hydride
To 30 mL of a dry diethyl ether solution of tribenzyltin hydride (15.74 g,
40 mmol) in a three-necked flask equipped with a condenser on top of which
was a CaCl2 tube, 1-ethynyl-1-cyclooctanol (6.08 g, 40 mmol) and dibenzoyl
peroxide (20 mg) were added. This mixture was kept under nitrogen. After
20 hr at room temperature with stirring, diethyl ether was evaporated, the resi-
due was recrystallized from ethanol to give 12.46 g (57.2%) of a colorless
solid, (Z)-1-[2-(tribenzylstannyl)vinyl]-1-cyclooctanol (1). m.p. 84–86 8C.
Anal. calcd. for C31H38OSn (FW 545): C, 68.26; H, 6.97; Sn, 21.83. Found
C, 68.22; H, 6.92; Sn, 21.78. IR: n(O–H): 3579; n(C–O): 1083;
n(O ! Sn): 522 cm21
.
1H NMR dH: 0.61 (1H, s, OH), 1.56 (14H, br,
C8H14), 2.28 (2H, s, CH2), 5.59, 6.65 (2H, d, J ¼ 13 Hz, CH55CH), 6.84–
7.22 (15H, m, 3C6H5) ppm. Hexabenzylditin was obtained as an insoluble
by-product.

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Ren et al.
Reaction of Compound (1) with Bromine or Iodine
Monochloride (Molar Ratio 1 : 1)
Bromine (0.1 mL, 1.98 mmol) dissolved in carbon tetrachloride (10 mL)
was added slowly to compound (1) (1.079 g, 1.98 mmol) dissolved in CCl4
(12 mL) at 25 8C. The color of bromine disappeared immediately. The
solvent was evaporated and the residue was recrystallized from cyclohexane
togive (Z)-1-[2-(dibenzylbromostannyl)vinyl]-1-cyclooctanol(2), as white crys-
tals, yield 0.78 g (73.4%), m.p. 56–58 8C. Anal. Calcd for C24H31BrOSn (FW
534): C, 53.93; H, 5.81; Sn, 22.28. Found: C, 53.88; H, 5.76; Sn, 22.21. IR:
1
n(O–H): 3577; n(C–O): 1085; n(O ! Sn): 545 cm21. H NMR dH: 2.28
(1H, s, OH), 1.47 (14H, br, C8H14), 2.36 (2H, s, CH2), 5.59, 6.63 (2H, d,
J ¼ 10 Hz, CH55CH), 7.07–7.37 (10H, m, 2C6H5) ppm. From the mother
liquor, benzyl bromide was separated and 0.5 mL CDCl3 was added to deter-
mine its 1H NMR spectrum. 1H NMR dH: 4.56 (2H, s, CH2), 7.06–7.14 (5H,
m, C6H5) ppm. It confirmed benzyl bromide.
An analogous procedure was used for the synthesis of (Z)-1-[2-(dibenzyl-
chlorostannyl)vinyl]-1-cyclooctanol (3), white crystals, yield 0.55 g (56.7%),
m.p. 112–114 8C. Anal. Calcd for C24H31ClOSn (FW 489.5): C, 58.84; H,
6.33; Sn, 24.31. Found: C, 58.80; H, 6.28; Sn, 24.29. IR: n(O–H): 3421;
1
n(C–O): 1054; n(O ! Sn): 546 cm21; H NMR dH: 2.65 (1H, s, OH), 1.55
(14H, br, C8H14), 2.79 (2H, s, CH2), 6.03, 6.64 (2H, d, J ¼ 13 Hz,
CH55CH), 7.04–7.24 (10H, m, 2C6H5) ppm.
Reaction of Compound (1) with Bromine or Iodine
Monochloride (Molar Ratio 1 : 2)
Bromine (0.2 mL, 3.96 mmol) dissolved in carbon tetrachloride (20 mL)
was added slowly to compound (1) (1.079 g, 1.98 mmol) dissolved in CCl4
(25 mL) at 210 8C. When the solution became almost colorless, carbon tetra-
chloride was evaporated. The residue was recrystallized from cyclohexane
to give (Z)-1-[2-(benzyldibromostannyl)vinyl]-1-cyclooctanol (4), as white
needles, yield 0.75 g (72.3%), m.p. 126–128 8C. Anal. Calcd for C17H24Br2-
OSn (FW 523): C, 39.01; H, 4.59; Sn, 22.75. Found: C, 38.98; H, 4.51; Sn,
1
22.70. IR: n(O–H): 3422; n(C–O): 1050 cm21; n(O ! Sn): overlapped. H
NMR dH: 3.13 (1H, s, OH), 1.54 (14H, br, C8H14), 3.02 (2H, s, CH2), 6.07,
6.96 (2H, d, J ¼ 12 Hz, CH55CH), 7.20–7.86 (5H, m, C6H5) ppm.
An analogous procedure was used for the synthesis of (Z)-1-[2-(benzyldi-
chlorostannyl)vinyl]-1-cyclooctanol (5), white crystals, yield 0.58 g (68.2%),
m.p. 160–161 8C. Anal. Calcd for C17H24Cl2OSn (FW 434): C, 47.00; H,
5.53; Sn, 27.42. Found: C, 46.98; H, 5.50; Sn, 27.40. IR: n(O–H): 3409;

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(Z)-1-[2-(Tribenzylstannyl)vinyl]-1-cyclooctanol
569
1
n(C–O): 1083; n(O ! Sn): 520 cm21; H NMR dH: 3.18 (1H, s, OH), 1.65
(14H, br, C8H14), 3.10 (2H, s, CH2), 6.26, 6.97 (2H, d, J ¼ 10 Hz,
CH55CH), 7.23–7.72 (5H, m, C6H5) ppm.
RESULT AND DISCUSSION
Syntheses
The addition of ethyne to cyclooctanone in the presence of t-BuOK
according to the literature method[5] yielded 1-ethynylcyclooctanol in good
yield (78%). Hydrostannation of this alkyne with tribenzyltin hydride using
dibenzoyl peroxide as a catalysts yielded compound (1) [Eq. (1)]. Compound
(1) was purified by crystallization from ethanol. Compound (1) shows charac-
teristic ethylenic proton signals at 5.59 and 6.65 ppm, namely two doublets
3
with JHC55CH ¼ 13 Hz.
The reaction of compound (1) with halogens (Br2 or ICl) in 1 : 1 or 1 : 2
molar ration yielded compounds (2)–(5) quantitatively [Eqs. (2) and (3)].
Hence, the benzyl-tin bond is cleaved regiospecifically. Such regiospecific
cleavages have been observed previously in organotin compounds containing
donor groups.[2] Compound (1) reacts with one equivalent of halogen, the
vinylic protons appear at 5.59 and 6.63 ppm (2); 6.03 and 6.64 ppm (3),
3
3
respectively, again as doublets JHC55CH ¼ 10 Hz and JHC55CH ¼ 13 Hz. The
presence of vinylic protons clearly shows that the benzyl-tin bond is cleaved
by halogen and the –CH55CH–Sn bond remains intact. Therefore, compo-
unds (2) and (3) are identified as (Z)-1-[2-(dibenzylhalostannyl)vinyl]-1-
cyclooctanols. After the addition of a second equivalent of halogen, the vinylic
protons change to 6.07 and 6.96 ppm (4); 6.26 and 6.97 ppm (5) as doublets
3
3JHC55CH ¼ 12 Hz and JHC55CH ¼ 10 Hz. This shows that the second group
cleaved by halogen again is a benzyl group. Thus, compounds (4) and (5)
are (Z)-1-[2-(benzyldihalostannyl)-vinyl]-1-cyclooctanols.
In addition, we have separated the side product benzyl bromide, and have
recorded its 1H NMR spectrum confirming it as of benzyl bromide.
X-ray Structure Analysis of Compound (1)
The structure of (Z)-1-[2-(tribenzylstannyl)vinyl]-1-cyclooctanol (1) has
been determined by x-ray diffraction analysis and is shown in Fig. 1. Com-
pound (1) crystallizes from alcohol in the monoclinic space group P21/c
˚
˚
˚
with a ¼ 9.348(1) A, b ¼ 26.143(1) A, c ¼ 10.705(1) A, b ¼ 95.09(1)8,
V ¼ 2605.9(1) A , Z ¼ 4, Dc ¼ 1.390 g cm23, m ¼ 10 cm21, final R ¼ 0.033
3
˚

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Ren et al.
Figure 1. Structure of compound (1).
2
2
for 3165 observed reflection (jFj ꢀ 8sjFj ). Selected bond lengths and angles
are given in Tables 1 and 2. Crystal data and details of the x-ray studies are
listed in Table 3.
The tin atom is coordinated by the C(10) and O(1) atoms of the 1-ethnyl-
1-cyclooctanol ligand, and three benzyl groups. The Sn ꢂ ꢂ ꢂ O(1) bond length
˚
of 2.807(5) A for (1), clearly represents significant bonding interactions.
The geometry about the atom is thus best described as being based on a
distorted trigonal bipyramid with the axial positions occupied by the C(110)
and O(1) atoms; O(1)–Sn(1)–C(110) 167.9(1)8. The tin atom is five-
coordinate, being bonded to three benzyl groups, the vinyl C(10) atom
a
˚
Table 1. Selected bond lengths (A) in compound (1).
O(1)–Sn
2.807(5)
2.137(5)
2.180(5)
1.509(7)
1.328(7)
1.495(7)
Sn(1)–C(110)
Sn(1)–C(1100)
O(1)–C(1)
2.182(5)
2.168(5)
1.425(6)
1.554(8)
1.492(8)
1.500(7)
Sn(1)–C(10)
Sn(1)–C(11)
C(1)–C(9)
C(2)–C(3)
C(11)–C(12)
C(1100)–C(1200)
C(9)–C(10)
C(110)–C(120)
aStandard deviations are given in parentheses.

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(Z)-1-[2-(Tribenzylstannyl)vinyl]-1-cyclooctanol
Table 2. Selected bond angles (deg) in compound (1).a
571
O(1)–Sn(1)–C(10)
O(1)–Sn(1)–C(110)
C(11)–C(12)–C(13)
C(10)–Sn(1)–C(110)
C(110)–Sn(1)–C(1100)
65.7(1)
167.9(1)
120.9(5)
103.1(1)
110.4(2)
O(1)–Sn(1)–C(11)
O(1)–Sn(1)–C(1100)
C(10)–Sn(1)–C(11)
Sn(1)–O(1)–C(1)
85.1(1)
75.9(1)
115.7(1)
110.0(2)
104.6(2)
C(11)–Sn(1)–C(1100)
aStandard deviations are given in parentheses.
Table 3. Date collection and structure refinement parameters.
Formula unit
Crystal size
C31H38OSn
0.24 mm ꢁ 0.32 mm ꢁ 0.38 mm
4458, 55
No. and 2u range, degree of
reflections for lattice parameter
Space group
P21/c
˚
a, (A)
9.348(1)
26.143(1)
10.705(1)
95.09(1)
2605.9(1)
4
˚
b, (A)
˚
c, (A)
b, 8
3
˚
V, (A )
Z
Dcalc (g cm23
mMoKa (cm21
Radiation
)
1.390
10
MoKa
)
˚
l, (A)
Monochromator
2umax, (deg)
0.71073
graphite
55
Index range (h, k, l)
No. of ind rflns
Meads
0–12, 0–33, 213–13
4458
3165
2
2
Obsd(jFj . 8sjFj )
Method used to solve structure
Refinement
Direct methods (SHELX86)
Anisotropic least squares
(SHELXS86) using F2
2
Weighting scheme
H atoms
W ¼ 1/sjFj
All hydrogen atoms were obtained
from geometric and difference
Fourier calculations.
0.033, 0.042, 0.203
R, Rw, S
Max height in final DF map
0.47

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Ren et al.
˚
˚
[2.137(5) A] and the O(1) atom of the hydroxyl group [2.807(5) A]. The
equatorial plane is being defined by the three carbon atoms C(10), C(11),
and C(1100).
ACKNOWLEDGMENT
This project was supported by Dalian University of Technology Innovate
Foundation.
REFERENCES
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ol: evidence by x-ray diffraction analysis and iodo demetalation. Organo-
metallics 1990, 9, 2199–2201.
2. Gielen, M.; Huade, P.; Willem, R.; De Vos, D. Antitumor composition and
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characterization of (Z)-1-[2-(tribenzylstannyl)vinyl]-1-cycloheptanol.
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cation to preparation of organotin compounds. J. Dalian Univ. Technol.
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Received February 24, 2003
Accepted December 3, 2003
Referee I: A. Rammo
Referee II: V. Huch

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