From a stannene and quinones to various tin-containing heterocycles

Article abstract of DOI:10.1021/om801198y

Some fused tin-containing heterocycles were prepared from the novel thermally stable stannene Tip₂Sn=CR₂ (1; Tip = 2,4,6-triisopropylphenyl, CR₂ = 2,7-di-terf-butylfluorenylidene) and a series of quinones. Reaction of 1 wi

Full text of DOI:10.1021/om801198y

2294
Organometallics 2009, 28, 2294–2299
From a Stannene and Quinones to Various Tin-Containing
Heterocycles
Dumitru Ghereg,† Henri Ranaivonjatovo,† Nathalie Saffon,‡ Heinz Gornitzka,*,§ and
Jean Escudie´*,†
UniVersite´ de Toulouse, UPS, LHFA, 118 Route de Narbonne, F-31062 Toulouse, France, CNRS, LHFA,
UMR 5069, F-31062 Toulouse Cedex 09, France, Structure Fe´de´ratiVe Toulousaine en Chimie
Mole´culaire, FR 2599, UniVersite´ Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex 09,
France, and Laboratoire de Chimie de Coordination du CNRS, 205 Route de Narbonne,
31077 Toulouse Cedex 04, France
ReceiVed December 19, 2008
Some fused tin-containing heterocycles were prepared from the novel thermally stable stannene
Tip2SndCR2 (1; Tip ) 2,4,6-triisopropylphenyl, CR2 ) 2,7-di-tert-butylfluorenylidene) and a series of
quinones. Reaction of 1 with 1,4-benzoquinone afforded the unexpected conjugated 1,4-distannoxy-1,3-
cyclohexadiene 2, according to a double [2+3] cycloaddition. In contrast, in 1,4-naphthoquinone and
9,10-anthraquinone the aromatic ring fused to the quinonic moiety was involved in the reaction, leading
to hexahydrodioxadistannapyrene 3 and hexahydrodioxadistannabenzopyrene 4. Ortho-quinones, such
as 9,10-phenanthrenequinone, gave by [2+4] cycloaddition the dioxastannacyclohexene 5. All compounds
1
were submitted to detailed H and 13C NMR study. The structures of 2, 3, and 5 were determined by
X-ray crystallography.
only by trapping reactions, have been kinetically stabilized and
their chemical behavior has been largely explored. However,
this is not the case for the stannenes >SndC<, which were
isolated later,2-8 and therefore, relatively little is known about
their chemical reactivity. Only a few reactions have been
described, particularly with protic reagents,2,6,7 benzophenone,9
2,3-dimethylbutadiene,7 methyl iodide,6b and LiAlH4.6b Inves-
tigation of the chemical behavior of the transient stannene
Me2SndC(SiMe3)2 has been limited to its reaction with alkenes,
dienes, azides, and phenyllithium.10 Very recently, we reported
the synthesis of a new stannene Tip2SndCR2 (1; Tip ) 2,4,6-
triisopropylphenyl, CR2 ) 2,7-di-tert-butylfluorenylidene), ex-
hibiting a remarkable thermal stability.11 Despite the large steric
hindrance around the SndC bond, among the shortest known
to date (2.003(5) Å), stannene 1 has shown a high chemical
reactivity toward some saturated and R,ꢀ-unsaturated carbonyl
compounds.11 However, the chemistry of stannenes remains still
poorly documented, and so, relatively little effort has been
expended in the application of these species in organic and
organometallic chemistry.
Introduction
Metallaalkenes of group 14 elements >MdC< (M ) Si, Ge,
Sn), heavier congeners of alkenes, have received great attention
because of their synthetic challenge as well as of their reactivity
and have been the subject of a number of theoretical, structural,
and mechanistic studies.1 Although these elements belong to
the same periodic group as carbon, they demonstrate much lesser
ability to form stable double bonds. Over the past two decades,
such derivatives, which for a long time have been characterized
* Corresponding author. E-mail: escudie@chimie.ups-tlse.fr.
† UPS, LHFA, Universite´ de Toulouse and CNRS, LHFA, UMR 5069.
‡ Universite´ Paul Sabatier.
§ Laboratoire de Chimie de Coordination du CNRS.
(1) For reviews, see: (a) Power, P. P. Chem. ReV. 1999, 99, 3463. (b)
Okazaki, R.; West, R. AdV. Organomet. Chem. 1996, 39, 231. (c) West, R.
Polyhedron 2002, 21, 467. (d) Sekiguchi, A.; Lee, V. Ya. Chem. ReV. 2003,
103, 1429. (e) Tokitoh, N. Acc. Chem. Res. 2004, 37, 86. (f) Brook, A. G.;
Brook, M. A. AdV. Organomet. Chem. 1996, 39, 71. (g) Mu¨ller, T.; Ziche,
W.; Auner, N. In The Chemistry of Organic Silicon Compounds; Rap-
poport, Z., Apeloig, Y., Eds.; Wiley: New York, 1998; Vol. 2, Chapter 16.
(h) Baines, K. M.; Stibbs, W. G. AdV. Organomet. Chem. 1996, 39, 275.
(i) Escudie´, J.; Ranaivonjatovo, H. AdV. Organomet. Chem. 1999, 44, 113.
(j) Escudie´, J.; Couret, C.; Ranaivonjatovo, H. J. Coord. Chem. ReV. 1998,
178, 565. (k) Lee, V. Ya.; Sekiguchi, A. Organometallics 2004, 23, 2822.
(2) Berndt, A.; Meyer, H.; Baum, G.; Massa, W.; Berger, S. Pure Appl.
Chem. 1987, 59, 1011.
The stannenes could be a valuable source of tin heterocycles,
for which still limited syntheses are known: the traditional
methods for preparing such compounds are based on reactions
of R2SnCl2 derivatives with dioximes,12 triethyl- and triallylbo-
ranes,13 and organozirconium complexes.14 One important
(3) Meyer, H.; Baum, G.; Massa, W.; Berger, S.; Berndt, A. Angew.
Chem., Int. Ed. Engl. 1987, 26, 546.
(4) Weidenbruch, M.; Kilian, H.; Stu¨rmann, M.; Pohl, S.; Saak, W.;
Marsmann, H.; Steiner, D.; Berndt, A. J. Organomet. Chem. 1997, 530,
255.
(5) Stu¨rmann, M.; Saak, W.; Weidenbruch, M.; Berndt, A.; Schesch-
kewitz, D. Heteroat. Chem. 1999, 10, 554.
(6) (a) Anselme, G.; Ranaivonjatovo, H.; Escudie´, J.; Couret, C.; Satge´,
J. Organometallics 1992, 11, 2748. (b) Anselme, G.; Declercq, J.-P.;
Dubourg, A.; Ranaivonjatovo, H.; Escudie´, J.; Couret, C. J. Organomet.
Chem. 1993, 458, 49.
(9) Kandri Rodi, A.; Anselme, G.; Ranaivonjatovo, H.; Escudie´, J. Chem.
Heterocycl. Compd. 1999, 1098.
(10) (a) Wiberg, N.; Vasisht, S.-K. Angew. Chem., Int. Ed. Engl. 1991,
30, 93. (b) Wiberg, N.; Wagner, S.; Vasisht, S.-K. Chem.-Eur. J. 1998, 4,
2571. (c) Wiberg, N.; Passler, T.; Wagner, S.; Polborn, K. J. Organomet.
Chem. 2000, 598, 292. (d) Wiberg, N.; Passler, T.; Wagner, S. J. Organomet.
Chem. 2000, 598, 304.
(7) Mizuhata, Y.; Takeda, N.; Sasamori, T.; Tokitoh, N. Chem. Commun.
2005, 5876.
(8) The SndC bond is included in the aromatic structure of a stannan-
aphthalene: Mizuhata, Y.; Sasamori, T.; Takeda, N.; Tokitoh, N. J. Am.
Chem. Soc. 2006, 128, 1050.
(11) Abdoul Fatah; El Ayoubi, R.; Gornitzka, H.; Ranaivonjatovo, H.;
Escudie´, J. Eur. J. Inorg. Chem. 2008, 2007.
(12) Singh, M. S.; Singh, A. K. Tetrahedron Lett. 2005, 46, 315.
(13) Wrackmeyer, B.; Pedall, A.; Milius, W.; Tok, O. L.; Bubnov, Y. N.
J. Organomet. Chem. 2002, 649, 232.
10.1021/om801198y CCC: $40.75
2009 American Chemical Society
Publication on Web 03/03/2009

Tin-Containing Heterocycles
Organometallics, Vol. 28, No. 7, 2009 2295
application of organotin compounds is their use as biocides.15
Moreover, it has been shown that Sn-O, Sn-N, and Sn-S
bonds increase this activity, for example against tumoral cells
MCF-7 and WiDr.16 The understanding of the structural bases
of the biological effects needs a careful investigation of the
electronic environment, geometry, and stereochemistry in these
compounds. This motivated us to explore the chemical behavior
of 1 toward various para-quinones (1,4-benzoquinone, 1,4-
naphthoquinone, and 1,4-anthraquinone) and one ortho-quinone
(9,10-phenanthrenequinone); such compounds are suitable re-
agents to give Sn-O-containing heterocycles, displaying a
potential biological activity. Although para-quinones offer
several possibilities for cycloaddition reaction with “heavier”
alkenes due to their CdO and CdC unsaturations, there is, to
the best of our knowledge, no report on this topic.
Results and Discussion
Figure 1. Molecular structure of 2 (thermal ellipsoids at the 50%
probability level). Hydrogen atoms and noncoordinated solvent
molecules are omitted; Tip and CR2 groups are simplified for clarity.
Selected bond lengths (Å) and angles (deg): Sn1-O1 2.03(1);
Sn1-C1 2.24(1); O1-C3 1.36(2); C1-C2 1.56(2); C2-C3 1.52(2);
C2-C2A 1.57(2); C3-C4 1.34(2); C4-C4A 1.45(2); O1-Sn1-C1
84.3(4); C3-O1-Sn1 109.6(7); C2-C1-Sn1 101.1(6); C3-C2-C1
107.0(8);C3-C2-C2A115.1(6);C4-C3-C2122.9(11);O1-C3-C2
115.6(10); C3-C4-C4A 121.9(7).
(a) Reaction of 1 with para-Quinones: 1,4-Benzoquinone.
Normally, two types of reactions could be expected: a [2+2]
cycloaddition onto the carbonyl groups, leading to oxastanne-
tanes, as with saturated nonenolizable carbonyl compounds,9,11
or onto the CdC double bond10a to afford corresponding
stannacyclobutanes. A [2+4] cycloaddition onto the conjugated
CdC-CdO system could be excluded because of its transoid
conformation. To our surprise, 1 showed a totally nonclassical
behavior.
vicinal carbon atoms should be strongly disfavored and was
rather unexpected. The formation of 2 in 86% yield confirmed
the high reactivity of 1. Compound 2 can be handled in air in
the solid state; nevertheless, as observed by 119Sn NMR
spectroscopy, it slowly decomposed at room temperature in Et2O
or THF in the presence of air/oxygen and light, with the
formation of still unidentified products.
The treatment of an ethereal solution of 1 with 1,4-
benzoquinone, under an argon atmosphere at -78 °C, led to a
progressive disappearance of the purple color of stannene. After
the usual workup (replacement of solvents by pentane and
filtration of lithium salt) the cycloadduct 2 (eq 1) was isolated
by recrystallization as a yellow powder. As shown by analytical
data, the reaction occurred with the involvement of both CdO
and CdC unsaturations. The structure of 2 was established by
X-ray crystallography and supported by the spectroscopic (1H,
13C, and 119Sn NMR) and mass spectrometry analyses.
All attempts to crystallize compound 2 resulted in poor quality
crystals; therefore, the structural details obtained by X-ray will
not be discussed. Nevertheless, the general connectivity of the
molecule could be established unambiguously. This X-ray study
(Figure 1), showed the presence of a planar 1,3-cyclohexadiene
ring with two conjugated double bonds (1.34(2) Å) as a central
unit, having the two CR2 groups in a trans position.
As expected, both tin atoms in 2 are equivalent, which is
confirmed by the presence of only one signal at -17.90 ppm
1
in the 119Sn NMR spectrum. The H NMR spectrum reveals
that all methyl groups of the ortho isopropyl units are not
equivalent, displaying eight signals spread over a large range
(from -0.34 to 1.24 ppm). These different resonances resulted
both from the diastereotopy of methyl and 2,4,6-triisopropy-
lphenyl groups and from the slow rotation around the ipso-C-Sn
bonds on the chemical shift time scale. The 13C NMR spectrum
presents the same complexity with nonequivalence not only of
the isopropyl groups but also of the carbon atoms of the phenyl
rings of the Tip groups. The complete assignment of all these
signals was obtained from homonuclear (COSY) and hetero-
nuclear (HSQC and HMBC) experiments.
In mass spectrometry, besides the molecular peak, fragments
corresponding to stannylene Tip2Sn - 1, to starting Tip2SndCR2
- 1, and to Tip2SnO - 1 were also found.
1,4-Naphthoquinone and 9,10-Anthraquinone. In order to
extend our study on the reactivity of stannenes with other para-
quinones, we decided to use fused aromatic quinones. Ef-
fectively, a different reaction occurred by addition of 0.5 equiv
of 1,4-naphthoquinone to an ethereal solution of 1, involving
the oxygen and the ortho carbon atoms of the adjacent aromatic
ring system. This reaction afforded nearly quantitatively hexahy-
drodioxadistannapyrene 3, which was purified by crystallization
as an air-stable compound (Scheme 1). In contrast to the case
of 1,4-benzoquinone, the formal [2+3] cycloadditions of the
SndC double bond to the C-CdO units of the quinonic ring
were not observed. Suitable crystals for structure determination
were obtained by slow evaporation of an ethereal solution at
room temperature. The X-ray analysis showed the presence of
The observed regiochemistry leading to five-membered rings
with the very bulky 2,7-di-tert-butylfluorenylidene units on
(14) Pirio, N.; Bredeau, S.; Dupuis, L.; Schu¨tz, P.; Donnadieu, B.; Igau,
A.; Majoral, J.-P.; Guillemin, J.-C.; Meunier, P. Tetrahedron 2004, 60, 1317.
(15) (a) Mahon, M. F.; Molloy, K. C.; Waterfield, P. C. J. Organomet.
Chem. 1989, 361, C5. (b) Gielen, M. Appl. Organomet. Chem. 2002, 16,
481.
(16) Yang, P.; Guo, M. Coord. Chem. ReV. 1999, 185, 189.

2296 Organometallics, Vol. 28, No. 7, 2009
Ghereg et al.
Figure 2. Molecular structure of 3 (thermal ellipsoids at the 50%
probability level). Hydrogen atoms and noncoordinated solvent
molecules are omitted; Tip and CR2 groups are simplified for clarity.
Selected bond lengths (Å) and angles (deg): Sn1-O1 2.009(2);
Sn1-C1 2.241(3); C1-C2 1.585(3); C2-C8 1.524(4); C8-C9
1.403(4); O1-C9 1.371(3); C2-C3 1.505(4); C3-C4 1.321(4);
C7-C81.410(4);C9-C101.389(4);C10-C111.382(4);O1-Sn1-C1
92.6(8); C2-C1-Sn1 106.9(2); C8-C2-C1 116.1(2); C9-C8-C2
118.4(2); O1-C9-C8 121.5(2); C9-O1-Sn1 119.4(2).
Figure 3. Molecular structure of 5 (thermal ellipsoids at the 50%
probability level). Hydrogen atoms are omitted and Tip and CR2
groups are simplified for clarity. Selected bond lengths (Å) and
angles (deg): Sn1-O1 2.032(2); Sn1-C1 2.225(2); O2-C1
1.446(2); O1-C22 1.353(2); O2-C23 1.397(2); C22-C23 1.359(3);
C23-C24 1.435(3); C24-C29 1.415(3); C29-C30 1.451(3);
C30-C35 1.416(3); C22-C35 1.449(3); O1-Sn1-C1 91.97(6);
C22-O1-Sn1 122.27(12); C23-O2-C1 116.31(15); O2-C1-Sn1
101.69(12); O1-C22-C23 124.39(18); C22-C23-O2 121.50(18).
Scheme 1
The loss of aromaticity in the fused benzene ring of the
quinones carries a high thermodynamic cost, partially negating
the energy release from the formation of the strong Sn-O bond.
This a priori surprising behavior of 1 can also be explained by
the formation of two thermodynamically stable six-membered-
ring heterocycles and by the aromatization of the previous
quinonic ring system.
Compounds 3 and 4 have been clearly characterized by
physicochemical methods. The presence of two stereogenic
centers and the large steric hindrance around the Sn atom,
leading to slow rotation around the Sn-C bonds and conse-
1
quently broad signals, complicated the assignment of the H
and 13C signals. Once the hydrogen atoms of compounds 3 and
4 were assigned by COSY spectra, they were correlated with
the 13C resonances by HSQC and HMBC experiments. Ortho-
isopropyl groups and meta-hydrogen atoms of two 2,4,6-
a tetracyclic compound. A view of the molecule 3 with the
atomic labeling scheme is shown in Figure 2. The ring
containing C7-C12 atoms has been converted into an aromatic
ring, as confirmed by C-C distances: C7-C8 1.410(4); C8-C9
1.403(4); C9-C10 1.389(4); C10-C11 1.382(4) Å. The former
aromatic ring of the 1,4-naphthoquinone is no longer aromatic,
retaining only one double bond (C3-C4 1.321(4) Å), whereas
C2-C8 (1.524(4) Å) and C2-C3 (1.505(4) Å) are typical single
bonds. Because of the rigid planar C2-C8dC9-O1 and
C5-C7dC12-O2 units, only one conformer (boat form) has
been observed for both formed six-membered tin heterocycles.
Their bond lengths and angles are very similar to those reported
previously for the structurally close 1-oxa-2-stanna-5-cyclo-
hexene obtained from 1 and crotonaldehyde.11
1
triisopropylphenyl units are no longer equivalent in their H
NMR spectra. The corresponding signals for the two other 2,4,6-
triisopropylphenyl units are too broad to be observed. By
contrast, the methyl groups of para-isopropyl units appear as
sharp doublets with very similar chemical shifts (for exemple,
at 1.10, 1.11, 1.15, and 1.17 ppm in the case of 3) since they
are not influenced by the slow rotation around the Sn-C bond.
The 13C NMR spectra of compounds 3 and 4 display signals at
62.77 ppm (with 1J117/119Sn-C coupling constant of 366.0/383.1
Hz) and 61.88 ppm for quaternary CR2 carbon atoms. It is worth
noting that the carbon resonances of methyl groups in 3 and 4
all appear within the range 22.81-28.82 ppm and 22.84-28.39
ppm, respectively.
Compounds 3 and 4 showed some similarities in their mass
spectra: the molecular peak and the cleavage leading to
Tip2SndCR2 were observed.
(b) Reaction of 1 with ortho-quinones: 9,10-Phenanthrene-
quinone. When a purple solution of 1 in diethyl ether was
treated with 1 equiv of 9,10-phenanthrenequinone, a white
powder was isolated from the reaction mixture in 68% yield.
Although the mass spectrum confirmed the 1:1 stoichiometry
The reaction of 9,10-anthraquinone with 1 proceeded in a
similar fashion to 1,4-naphthoquinone, leading to hexahy-
drodioxadistannabenzopyrene 4 (Scheme 1), according to two
[2+4] cycloadditions.
In both cases, only one isomer (with trans disposition of CR2
groups) was observed: 119Sn NMR spectra: -31.00 and -24.48
ppm for 3 and 4, respectively.

Tin-Containing Heterocycles
Organometallics, Vol. 28, No. 7, 2009 2297
of the reaction, the 1H and 13C NMR spectra performed at room
temperature did not provide much conclusive information about
the structure of the formed compound. In fact, due to an
vacuum-line, Schlenk, and cannula techniques, with solvents being
distilled over standard drying agents and degassed before use. 1,4-
Naphthoquinone was recrystallized from diethyl ether prior to use.
All other reagents were purchased from Aldrich and were used
without further purification. Deuterated solvents were dried and
stored over 4 Å molecular sieves. NMR spectra were recorded in
CDCl3 on a Bruker Avance 300 instrument at the following
frequencies: 300.13 MHz (1H, reference TMS), 75.47 MHz
(13C{1H}, reference TMS), 111.92 MHz (119Sn{1H}, reference
Me4Sn). 1H and 13C{1H} NMR assignments were confirmed by 1H
COSY, HSQC (1H-13C), and HMBC (1H-13C) experiments. Mass
spectra were measured on a Nermag R10-10 spectrometer by CI
(NH3 or CH4). Melting points were determined on a Leitz
microscope heating stage 250 or Electrothermal apparatus (capil-
lary). Elemental analyses were performed by the “Service de
Microanalyse de l’Ecole de Chimie de Toulouse”. The yields were
calculated from the starting precursor Tip2Sn(F)-CHR2.
1
important steric congestion in 5 (eq 2), the H NMR spectrum
displayed broad signals in the area of aliphatic groups. The
unequivocal structural elucidation of the dioxastannacyclohexene
5 was provided by the X-ray analysis (Figure 3). This study
clearly showed that 9,10-phenanthrenequinone binds to the
SndC double bond of 1 through oxygen atoms of the
O)C-CdO unit, as generally observed in the case of various
double-bonded compounds of group 14 (>GedC<17 and
>MdP-,18 M ) Ge, Sn) with ortho-quinones, such as tetra-
chloro-o-benzoquinone, 3,5-di-tert-butyl-o-benzoquinone, and
1,2-naphthoquinone. In addition, a similar [2+4] cycloaddition
has also been reported between this quinone and a stable fused
bicyclic disilene.19 The X-ray structure of 5 displayed a
tetracyclic compound with two oxygen and one tin atom; the
phenanthrene fragment is perfectly planar, whereas the diox-
astannacyclohexene ring adopts a slightly distorted sofa con-
formation with the C1 atom being 0.733 Å out of the mean
planeO2-C23-C22-O1-Sn1.ThetorsionangleC23-C22-O1-Sn1
is 27.3°. Noteworthy is also the elongation of the Sn1-C1 bond
(2.225(2) Å) due to the high steric hindrance of the bulky Tip
and CR2 groups.20
All data for structures were collected at low temperature using
an oil-coated shock-cooled crystal on a Bruker-AXS Apex II
diffractometer with Mo KR radiation (λ ) 0.7107 Å) and are
summarized in Table 1. The structures were solved by direct
methods21 and all non-hydrogen atoms were refined anisotropically
using the least-squares method on F2.22
For the 1H and 13C NMR study, the carbon atoms of the fluorenyl
group are numbered as shown in Chart 1. Some signals of
o-CHMeMe′ and m-CH of 2,4,6-triisopropylphenyl groups were
not observed because of the coalescence caused by their hindered
rotation. Due to many, in part, overlapping signals, or to low
solubility of compounds in deuterated solvents, JSnC coupling
constants cannot be given in some cases.
Synthesis of Stannene 1. Stannene 1 was prepared as previously
described11 by dropwise addition of 1 equiv of tert-butyllithium
(1.7 M in pentane) to a solution of fluorostannane Tip2Sn(F)CHR2
(1.65 g, 2.00 mmol) in Et2O (20 mL) cooled to -78 °C. Warming
to room temperature afforded a purple solution; a 119Sn NMR
analysis showed the nearly quantitative formation of stannene 1.
Thus, all reactions were performed on the crude reaction mixture
of 1 containing LiF.
1
A dynamic H NMR experiment between 213 and 313 K in
toluene-d8 allowed the determination of the rotation barrier
(18.34 kcal/mol, Tc ) 303 K) of one Tip group around the ipso-
C-Sn bond from the evolution of the methyl signals; this rather
high rotation barrier reflects the great steric hindrance caused
by the large Tip and CR2 groups. The signals in the aliphatic
zone appear clearly defined around 263 K, showing 12 doublets
between 0.29 and 1.78 ppm for all nonequivalent methyl groups.
The high steric hindrance is also probably responsible for the
air and moisture stability of 5: addition of water to its THF
solution does not cleave the Sn-O bond.
Again, the well-known oxophilic character of tin and the
formation of the strong C-O bond should be involved as driving
forces in this reaction. Furthermore, the formation of six-
membered heterocycle 5 induces aromaticity on the central
quinonic ring.
Synthesis of 2. To a crude solution of 1 (2 mmol) in Et2O (20
mL) cooled to -78 °C was added 1 mmol of 1,4-benzoquinone
dissolved in 5 mL of Et2O. The reaction mixture was allowed to
warm to room temperature, and its color slowly turned from purple
to yellow. After overnight stirring and filtration of LiF, the solvent
was removed in vacuo and replaced by 10 mL of pentane.
Crystallization at -20 °C afforded pure 2 as a crystalline yellow
1
compound (1.47 g, 86%, mp 321 °C). H NMR: -0.34 and 0.60
(2d, 3JHH ) 6.0 Hz, 2 × 6H, o-CHMeMe′), -0.09, 0.51, 1.09, and
1.24 (4d, 3JHH ) 6.6 Hz, 4 × 6H, o-CHMeMe′), 0.27 and 0.61 (2d,
3JHH ) 6.3 Hz, 2 × 6H, o-CHMeMe′), 0.42 and 1.48 (2s, 2 × 18H,
3
tBu), 0.87, 0.89 and 3.57 (3sept, 3 × 2H, JHH ) 6.6 Hz,
In conclusion, depending on the para-quinone used, stannene
1 reacts in two different fashions, whereas in the case of ortho-
quinones the expected [2+4] cycloadduct is observed. The high
reactivity of 1 will allow further investigations on the potential
synthetic applications of this powerful building block.
3
o-CHMeMe′), 1.02 and 1.04 (2d, JHH ) 6.6 Hz, 2 × 6H,
p-CHMeMe′), 1.06 (d, 3JHH ) 6.6 Hz, 12H, p-CHMeMe′), 2.55-2.72
(m, 6H, o- and p-CHMeMe′), 2.95 (s, 2H, CH-CR2), 5.28 (s, 2H,
CHdC-O), 6.05 and 8.78 (2d, 4JHH ) 1.5 Hz, 4JSnH ) 13.2 Hz, 2
× 2H, H1 and H8), 6.33, 6.69, 6.77, and 6.88 (4d, 4JHH ) 1.5 Hz,
4JSnH ) 22.2 Hz, 4 × 2H, m-CH of Tip), 6.84 and 7.46 (2dd, 3JHH
) 8.1 Hz, 4JHH ) 1.5 Hz, 2 × 2H, H3 and H6), 7.47 and 7.72 (2d,
3JHH ) 8.1 Hz, 2 × 2H, H4 and H5). 13C NMR: δ 22.89, 22.92,
22.99, 23.43, 24.51, 24.81, 25.55, and 29.37 (o-CHMeMe′), 23.70,
23.81, 23.86, and 23.93 (p-CHMeMe’), 31.48 and 31.84 (CMe3),
Experimental Section
General Experimental Details. All experiments were performed
in flame-dried glassware under an argon atmosphere using standard
32.38 (3JSnC ) 21.0 Hz), 38.05 (3JSnC ) 26.2 Hz), 40.29 (3JSnC
)
(17) Meiners, F.; Haase, D.; Koch, R.; Saak, W.; Weidenbruch, M.
Organometallics 2002, 21, 3990.
(18) Kandri-Rodi, A.; Declercq, J.-P.; Dubourg, A.; Ranaivonjatovo, H.;
Escudie´, J. Organometallics 1995, 14, 1954.
(19) Kobayashi, H.; Iwamoto, T.; Kira, M. J. Am. Chem. Soc. 2005,
127, 15376.
31.7 Hz) and 40.42 (3JSnC ) 47.8 Hz) (o-CHMeMe), 34.04 (p-
CHMeMe), 34.11 and 35.34 (CMe3), 51.59 (2JSnC ) 67.8 Hz, 3JSnC
) 17.5 Hz, CH-CR2), 68.72 (CR2), 98.74 (3JSnC ) 27.0 Hz,
(20) MacKay, K. M. In The Chemistry of Organic Germanium, Tin and
Lead Compounds; Patai, S., Ed.;Wiley: Chichester, 1995; Vol. 1, Chapter
2.
(21) Sheldrick, G. M. SHELXS-97. Acta Crystallogr. 1990, A46, 467.
(22) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure
Refinement; University of Go¨ttingen, 1997.

2298 Organometallics, Vol. 28, No. 7, 2009
Ghereg et al.
Table 1. Crystal Data for 2, 3, and 5
2 · 2C5H12 3 · 1.5Et2O
5
empirical formula
fw
temperature (K)
cryst syst
space group
a (Å)
C118H168Sn2O2
1855.90
193(2)
monoclinic
C2/c
39.301(19)
12.990(7)
23.583(12)
118.413(8)
10 590(9)
4
C118H161Sn2O3.5
1872.85
193(2)
monoclinic
P21/n
21.4073(3)
14.5881(2)
34.8664(6)
102.277(1)
10 639.5(3)
4
C65H78SnO2
1010.02
193(2)
monoclinic
P21/c
22.8146(5)
10.7060(2)
23.4538(5)
101.133(1)
5620.9(2)
4
0.496
50 877
11 414 [R(int) ) 0.0387]
multiscans
11 414/0/631
1.007
b (Å)
c (Å)
ꢀ (deg)
volume (Å3)
Z
absorp coeff (mm-1
reflns collected
indep reflns
absorp corr
)
0.519
27 669
0.518
129 813
6394 [R(int) ) 0.3610]
multiscans
6394/183/639
0.936
R1 ) 0.0712,
wR2 ) 0.1104
R1 ) 0.2107,
wR2 ) 0.1553
0.759, -0.654
21 591 [R(int) ) 0.0733]
multiscans
21 591/253/1268
1.015
R1 ) 0.0386,
wR2 ) 0.0805
R1 ) 0.0635,
wR2 ) 0.0916
0.559, -0.710
data/restraints/params
goodness-of-fit on F2
final R indices (I > 2σ(I))
R1 ) 0.0288,
wR2 ) 0.0616
R1) 0.0461,
wR2 ) 0.0682
0.431, -0.283
R indices (all data)
largest diff peak, hole (e Å-3
)
Chart 1
4.95 (s, 2H, CHCR2), 6.48 (s, 2H, H1 or H8 of CR2), 6.70 (s, 2H,
m-CH of Tip), 6.90 (s, 4H, H1 or H8 of CR2 and 2 m-CH of Tip),
3
6.95 (s, 2H, CHdC-O), 7.15 and 7.34 (2d, JHH ) 8.1 Hz, 2 ×
3
2H, H3 and H6 of CR2), 7.66 and 7.71 (2d, JHH ) 8.1 Hz, 2 ×
2H, H4 and H5 of CR2). 13C NMR: δ 22.81, 23.13, 25.98, and
28.82 (o-CHMeMe′), 23.74, 23.87, 23.91, and 23.98 (p-CHMeMe′),
31.17 and 32.32 (CMe3), 34.09 (p-CHMeMe′), 34.46 and 35.03
(CMe3), 37.35 (3JSnC ) 27.0 Hz) and 40.39 (3JSnC ) 32.3 Hz) (o-
CHMeMe′), 39.38 (2JSnC ) 27.7 Hz, CH-CR2), 62.77 (1J119
)
SnC
383.1 Hz, J117 ) 366.0 Hz, CR2), 118.35 and 118.88 (C4 and
1
SnC
C5 of CR2), 119.51 (3JSnC ) 12.8 Hz, CHdC-O), 121.87 (m-CH
of Tip), 122.02, 122.63, and 123.17 (m-CH of Tip, C1 and C8),
123.34 and 123.68 (C3 and C6), 123.84 (CH-CHCR2), 125.25 (3JSnC
) 23.4 Hz, C-C-O), 136.54 (3JSnC ) 22.6 Hz) and 137.51 (3JSnC
) 25.6 Hz) (C12 and C13 of CR2), 140.85 and 145.28 (ipso-C of
Tip), 145.57 and 146.69 (2JSnC ) 19.6 Hz, C10 and C11 of CR2),
148.12 (4JSnC ) 13.6 Hz) and 149.05 (4JSnC ) 12.8 Hz) (C2 and
C7 of CR2), 149.68 (4JSnC ) 11.3 Hz) and 150.07 (4JSnC ) 12.1
CHdC-O), 117.91 and 118.61 (4JSnC ) 11.2 Hz, C4 and C5),
120.42 (3JSnC ) 27.5 Hz) and 124.14 (3JSnC ) 20.2 Hz) (C1 and
C8), 121.87, 122.04, 122.39, 123.44 (m-CH of Tip), 123.53 and
123.90 (5JSnC ) 16.1 Hz, C3 and C6), 135.37 (3JSnC ) 21.3 Hz)
and 137.37 (3JSnC ) 22.8 Hz) (C12 and C13), 141.44 and 144.45
(ipso-C of Tip), 145.40 (2JSnC ) 21.7 Hz) and 147.68 (2JSnC ) 35.2
Hz) (p-C of Tip), 152.41 (2JSnC ) 72.4 Hz) and 155.03 (2JSnC
)
37.7 Hz) (o-C of Tip), 153.02 (2JSnC ) 29.4 Hz, C-O). 119Sn NMR:
δ -31.00. MS m/z (% relative intensity): 1761 (M + 1, 100), 1558
(M - Tip + 1, 35), 1236 (M - Tip2Sn, 40), 801 (Tip2SndCR2 -
1, 12), 525 (Tip2Sn - 1, 65), 323 (TipSn, 80). Anal. Calcd for
C112H146Sn2O2 (1761.770): C, 76.36; H, 8.35. Found: C, 76.84; H,
Hz) (C10 and C11), 146.89 (4JSnC ) 14.7 Hz) and 149.22 (4JSnC
)
8.16.
21.3 Hz) (C2 and C7), 149.57 (4JSnC ) 11.2 Hz) and 149.98 (4JSnC
) 12.2 Hz) (p-C of Tip), 152.37, 152.80, 154.68 (2JSnC ) 37.6 Hz)
and 155.71 (2JSnC ) 39.8 Hz) (o-C of Tip), 153.30 (C-O). 119Sn
NMR: δ -17.90. MS m/z (% relative intensity): 1711 (M + 1,
15), 1508 (M - Tip + 1, 6), 1187 (M - Tip2Sn + 1, 5), 801
(Tip2SndCR2 - 1, 3), 541 (Tip2SnO - 1, 7), 525 (Tip2Sn - 1,
50), 323 (TipSn, 100). Anal. Calcd for C108H144Sn2O2 (1711.758)
C, 75.78; H, 8.48. Found: C, 75.61; H, 8.83.
1
4 (1.40 g, 77%, mp 348 °C): H NMR: δ 0.28 and 1.64 (2d,
3
3JHH ) 6.3 Hz, 2 × 6H, o-CHMeMe′), 0.46 and 0.48 (2d, JHH
)
6.6 Hz, 2 × 6H, o-CHMeMe′), 0.60 and 3.46 (2sept,3JHH ) 6.6
Hz, 2 × 2H, o-CHMeMe′), 0.83 and 0.94 (2s, 2 × 18H, tBu), 1.09,
3
1.10, 1.15, and 1.17 (4d, JHH ) 6.6 Hz, 4 × 6H, p-CHMeMe′),
3
2.71 and 2.76 (2sept, 2 × 2H, JHH ) 6.9 Hz, p-CHMeMe′), 4.95
3
(s, 2H, dCH-CHCR2), 5.17 (s, CHCR2 JSnH ) 75.9 Hz), 6.03 and
4
4
6.85 (2d, JHH ) 1.5 Hz, JSnH ) 9.9 Hz, 2 × 2H, H1 and H8),
Synthesis of 3 and 4. To a solution of stannene 1 (2 mmol) in
Et2O (20 mL) cooled to -78 °C was slowly added 1 mmol of 1,4-
naphthoquinone or 9,10-anthraquinone, respectively, dissolved in
10 mL of diethyl ether. The reaction mixture progressively turned
brown after 2 h of stirring at room temperature. After filtration of
lithium salts and crystallization from pentane, white crystals of 3
or 4 were obtained.
6.65 and 6.90 (2d, 4JHH ) 1.5 Hz, 4JSnH ) 27.4 Hz, 2 × 4H, m-CH
3
4
of Tip), 7.16 and 7.24 (2dd, JHH ) 8.4 Hz, JHH ) 1.5 Hz, 2 ×
2H, H3 and H6), 7.32-7.34 and 8.50-8.54 (2m, 2 × 2H, arom
H), 7.65 and 7.67 (2d, JHH ) 8.1 Hz, 2 × 2H, H4 and H5). 13C
3
NMR: δ 22.84, 24.12, 25.96, and 28.39 (o-CHMeMe′), 23.72, 23.83,
23.90, and 24.02 (p-CHMeMe′), 31.16 and 31.89 (CMe3), 34.04
and 34.13 (p-CHMe2), 34.45 and 34.61 (CMe3), 37.46 and 40.37
(o-CHMeMe′), 38.96 (CH-CR2), 61.88 (CR2), 118.20 and 118.96
(C4 and C5), 122.03 and 122.72 (m-CH of Tip), 122.37 (C1 or
C8), 123.27 and 123.45 (C3 and C6), 123.36 and 123.84 (arom
CH, C1 or C8), 123.93 (CH-CHCR2), 128.50 and 140.56 (CC-O),
136.86 and 137.55 (C12 and C13), 145.31 (ipso-C of Tip), 145.47
1
3 (1.31 g, 74%, mp 332 °C): H NMR: δ 0.43, 0.52, 0.54 and
1.50 (4d, 3JHH ) 6.6 Hz, 4 × 6H, o-CHMeMe′), 0.72 (br sept, 2H,
3JHH ) 7.0 Hz, o-CHMeMe′), 0.82 and 1.31 (2s, 2 × 18H, tBu),
1.10, 1.11, 1.15, and 1.17 (4d, 3JHH ) 6.6 Hz, 4 × 6H, p-CHMeMe′),
3
2.73 and 2.75 (2sept, JHH ) 7.2 Hz, 2 × 2H, p-CHMeMe′), 3.27
(sept, 2H, 3JHH ) 7.0 Hz, o-CHMeMe′), 4.81 (s, 2H, dCH-CHCR2),

Tin-Containing Heterocycles
Organometallics, Vol. 28, No. 7, 2009 2299
and 146.44 (C10 and C11), 148.00 and 148.98 (C2 and C7), 148.41
(C-O), 149.91 and 150.19 (p-C of Tip), 152.37 and 154.89 (o-C
of Tip). 119Sn NMR: δ -24.48. MS m/z (% relative intensity): 1811
(M + 1, 100), 1608 (M - Tip + 1, 30), 801 (Tip2SndCR2 - 1,
20), 525 (Tip2Sn - 1, 50), 323 (TipSn, 50). Anal. Calcd for
C116H148Sn2O2 (1811.820): C, 76.90; H, 8.23. Found: C, 76.51; H,
8.32.
Synthesis of 5. A solution of 9,10-phenanthrenequinone (0.42
g, 2 mmol) in toluene (30 mL) was added by syringe to the crude
solution of 1 (2 mmol) cooled to -78 °C. The initially purple
reaction mixture turned green on warming to room temperature.
After removal of LiF by filtration, diethyl ether was evaporated
under vacuum and replaced by pentane (25 mL). The fractional
crystallization at -20 °C afforded white crystals of 5 (1.38 g, 68%,
mp 262 °C). 1H NMR: δ 0.54-1.67 (m, 56H, CMe3, o- and
p-CHMeMe′ and 2 o-CHMeMe′), 2.83, 3.52, and 4.01 (br signals,
4H, 2 o- and 2 p-CHMeMe′), 6.79 (br s, 3H, m-CH of Tip), 7.05
(br s, 1H, m-CH of Tip), 7.19-7.35 (m, 6H), 7.54-7.70 (m, 5H)
and 8.67-8.73 (m, 2H) (arom H of CR2 except H4 or H5, arom H
of phenanthrenic moiety), 8.57 (d, 3JHH ) 8.1 Hz, 1H, H4 or H5).
13C NMR: δ 23.96, 30.93, 34.32 (CMe3, o- or p-CHMeMe′), 92.52
(CR2), 119.19, 121.74, 122.02, 122.07, 122.47, 122.96, 123.49,
125.34, 125.72, 126.08 (arom CH), 129.00, 130.26, 131.32, 134.30,
143.21, 143.39, 145.53, 149.63, 150.92 (arom C). 119Sn NMR: δ
-67.57. MS m/z (% relative intensity): 1010 (M, 100), 995 (M -
CH3, 12), 803 (Tip2SndCR2 + 1, 42), 735 (M - CR2 + 1, 30),
525 (Tip2Sn - 1, 10). Anal. Calcd for C65H78SnO2 (1010.020): C,
77.30; H, 7.78. Found: C, 77.83; H, 7.36.
Acknowledgment. We are grateful to the CNRS (contract
CNRS/JSPS no. PRC 450), the Agence Nationale pour la
Recherche (contract ANR-08-BLAN-0105-01), and the ME-
NESR for financial support of this work.
Supporting Information Available: CIF files for 2, 3, and 5.
This material is available free of charge via the Internet at
http://pubs.acs.org.
OM801198Y