Direct access to unsymmetrical tin hydrides through (hydridodiorganostannio)lithiums

Article abstract of DOI:10.1021/om960444x

Metalation of diorganostannanes R¹₂SnH₂ by lithium diisopropylamide afforded the corresponding (hydridodiorganostannio)lithiums, R¹₂SnHLi, which were stable at low temperature. Further reaction with alkyl halides led to functional unsymmetrically substituted alkyldiorganostannanes, R¹₂R²SnH. Tin hydrides with an ω-unsaturated substituent were stable at room temperature. With a 4-pentyl chain, they underwent a specific cyclization process, giving a stannacyclohexane under radical reaction conditions. A tin hydride with a tin-silicon bond could also be prepared.

Full text of DOI:10.1021/om960444x

Organometallics 1996, 15, 4469-4472
4469
Dir ect Access to Un sym m etr ica l Tin Hyd r id es th r ou gh
(Hyd r id od ior ga n osta n n io)lith iu m s
Marie-Franc¸oise Connil, Bernard J ousseaume,* and Michel Pereyre
Laboratoire de Chimie Organique et Organome´tallique, URA 35 CNRS, Universite´ Bordeaux I,
351, cours de la Libe´ration, 33405-Talence Cedex, France
Received J une 4, 1996X
Metalation of diorganostannanes R1 SnH2 by lithium diisopropylamide afforded the
2
corresponding (hydridodiorganostannio)lithiums, R1 SnHLi, which were stable at low
2
temperature. Further reaction with alkyl halides led to functional unsymmetrically
substituted alkyldiorganostannanes, R1 R2SnH. Tin hydrides with an ω-unsaturated
2
substituent were stable at room temperature. With a 4-pentyl chain, they underwent a
specific cyclization process, giving a stannacyclohexane under radical reaction conditions.
A tin hydride with a tin-silicon bond could also be prepared.
In tr od u ction
report here a new access to organotin hydrides involving
alkylation of novel (hydridodiorganostannio)lithiums.11
Organotin hydrides are an important class of orga-
notin compounds1 which have given rise to numerous
studies, as they are key intermediates in the prepara-
tion of tetraorganotins by hydrostannation and are very
convenient reducing agents in organic synthesis.2 Hy-
drostannation can be conducted under various condi-
tions involving different mechanisms. That allows, for
instance, from the same alkyne the selective preparation
of three isomeric adducts: the R-, the (Z)-â- and the (E)-
â-stannylalkenes,3 which are also very interesting re-
agents in organic synthesis for either transmetalation
with lithium compounds,4 or palladium-catalyzed cou-
pling reactions.5 Numerous applications in organic
synthesis have been developed for organotin hydrides
as reducing agents. These organotins are particularly
interesting, as they can operate under very mild condi-
tions in the presence of numerous functional groups and
are efficient not only with bromides and iodides but also
with alcohols.6
Almost all the applications of organotin hydrides are
conducted with tributyltin hydride, because its reactiv-
ity scope is wide enough for most studies. However,
recent works have shown that more sophisticated hy-
drides can be useful in organic synthesis either for an
improved selectivity or reactivity7,8 or for practical
convenience,9,10 indicating that research on methods of
preparation of organotin hydrides is still of interest. We
Resu lts a n d Discu ssion
The main route to triorganotin hydrides involves in
the last step the reaction of a tin-heteroatom bond,
usually a tin-halogen or a tin-oxygen bond, with
reducing agents such as silicon, aluminum, or boron
hydrides. This preparation is very convenient in the
synthesis of triorganotin hydrides with three identical
groups linked to the tin, as the starting materials are
easily available from tin tetrachloride in two steps,
tetraalkylation and redistribution. When unsymmetri-
cal triorganotin hydrides are required, the preparation
is longer, as the monoalkylation of dihalodiorganotins
is usually not selective enough to be of preparative use.12
It involves the alkylation of a diphenyltin dihalide, the
cleavage of one phenyl group of the resulting diorgano-
diphenyltin by hydrochloric acid or bromine, the alky-
lation of the resulting diorganophenyltin halide, the
cleavage of the phenyl group of the unsymmetrical
triorganophenyltin and then the reduction step. This
long, multistep route could be avoided if the alkylation
of (hydridodiorganostannio)lithiums by organic halides
were possible. In this method only two steps are
required to obtain an unsymmetrical triorganotin hy-
dride from a diorganotin dihalide: reduction of a dior-
ganotin dihalide in diorganotin dihydride and metala-
tion-alkylation. This route saves both time and cost.
Moreover, the coupling of a stannyllithium with an
organic halide is advantageous in that it avoids the
preparation of a Grignard reagent, which may be
difficult with some halides,13 and it is stereospecific,
which allows the preparation of optically active orga-
notins with very high enantiomeric excess from optically
active halides or tosylates.14
X Abstract published in Advance ACS Abstracts, September 15, 1996.
(1) Kupchik, E. J . In Organotin Compounds; Sawyer, A. K., Ed.;
Marcel Dekker: New York, 1971; p 7. Davies, A.; Smith, P. J . In
Comprehensive Organometallic Chemistry; Wilkinson, G., Stone, F. G.
A., Abel, E. W., Eds.; Pergamon Press: New York, 1979; p 584.
Neumann, W. P. Synthesis 1987, 665. Davies, A. In Comprehensive
Organometallic Chemistry, 2nd ed.; Wilkinson, G., Stone, F. G. A., Abel,
E. W., Eds.; Pergamon Press: New York, 1995; p 217.
(2) Pereyre, M.; Quintard, J . P.; Rahm A. In Tin in Organic
Synthesis; Butterworths: London, 1987. Wardell J . L. In Chemistry
of Tin; Harrison, P. G., Ed.; Blackie: Glasgow, Scotland, 1989; p 315.
(3) Omae, I. J . Organomet. Chem. Libr. 1989, 21, 171.
(4) Seyferth, D.; Weiner, M. A. J . Am. Chem. Soc, 1961, 83, 3583.
(5) Stille, J . K. Angew. Chem., Int. Ed. Engl. 1986, 25, 508. Mitchell,
T. N. Synthesis 1992, 803.
(6) Barton, D. H. R.; Motherwell, B. Pure Appl. Chem. 1981, 53, 15.
(7) Light, J .; Breslow, R. Tetrahedron Lett. 1990, 2957.
(8) Vedejs, E.; Duncan, S. M.; Haight, A. R. J . Org. Chem. 1993,
58, 3046.
Thus, the synthesis of (hydridodiorganostannio)lithi-
ums was attempted. (Triorganostannio)lithiums can be
(11) A preliminary account of this work was published in: Connil,
M. F.; J ousseaume, B.; Noiret, N.; Pereyre, M. Organometallics 1994,
13, 24.
(12) Wardell, J . L. In Chemistry of Tin; Harrison, P. G., Ed.;
Blackie: New York, 1989; p 146. See for instance: Marr, I. L.; Rosales,
D.; Wardell, J . L. J . Organomet. Chem. 1988, 349, 65.
(13) Wakefield, B. J . In Organomagnesium Methods in Organic
Synthesis; Academic Press: London, 1995.
(9) Ferkous, F.; Messadi, D.; De J eso, B.; Degueil-Castaing, M.;
Maillard, B. J . Organomet. Chem. 1991, 420, 315.
(10) Clive, D. L. J .; Yang, W. J . Org. Chem. 1995, 60, 2607.
S0276-7333(96)00444-X CCC: $12.00 © 1996 American Chemical Society

4470 Organometallics, Vol. 15, No. 21, 1996
Connil et al.
prepared by reaction of lithium with organotin chlo-
rides15 or organoditins,16 by reaction of lithium reagents
with organoditins,17 or by metalation of organotin
hydrides by lithium diisopropylamide.18 In our case, the
first two methods require the preparation of unstable
or unknown organotins, while the third one involves
easily available diorganotin dihydrides.19 Thus, di-
butyltin dihydride was treated with a THF-hexane
solution of lithium diisopropylamide, as in the procedure
developped by Still for the preparation of (triorga-
nostannio)lithiums18 (see Scheme 1). After a few min-
utes, methyl iodide was added. However, analysis of
the reaction mixture only revealed the presence of
tributyltin hydrides and cyclopolytins.20 The same
reaction was then conducted at lower temperature, and
its analysis was more gratifying, as it led to the isolation
of methyldibutyltin hydride in 45% yield. It was thus
possible to prepare an unsymmetrical triorganotin hy-
dride in this way.
recently, and in tin chemistry an example of a very
hindered reagent of the same type, [(2,4,6-tris(bis-
(trimethylsilyl)methyl)phenyl)(2,4,6-triisopropylphenyl)-
hydridostannio]lithium,23 has been independently11 ob-
tained by the metalation of the corresponding dihydride
by tert-butyllithium. The potential application of this
new (hydridodibutylstannio)lithium in the synthesis of
unsymmetrical triorganotin hydrides was tested with
other halides and extended to other diorganotin dihy-
drides. The coupling with a bromide, 1-bromopropane,
was attempted first. It gave the corresponding tin
hydride, propyldibutyltin hydride, in good yield (60%
yield). 1-Chloropropane gave equally good results (57%
yield).
The reaction was not limited to dibutyltin dihydrides.
It was general and could be extended to other hydrides,
such as dicyclohexyltin and diphenyltin dihydrides.
These (hydridostannio)lithiums coupled with 1-bro-
mopropane to give dicyclohexylpropyltin and diphenyl-
propyltin hydrides, respectively (Scheme 3).
Sch em e 1
Sch em e 3
Bu2SnH2 + iPr2NLi -iPr NH8
2
R2SnH2 + iPr2NLi -iPr NH8 R2SnHLi PrBr8
2
Bu2SnHLi MeI8 MeBu2Sn
PrR2SnH
R (% yield): c-C6H11 (63), Ph (50)
The existence of a (hydrodiorganostannio)lithium
intermediate was checked by its reaction with deute-
rium oxide. Addition of deuterium oxide to a solution
of dibutyltin dihydride which had been treated with
lithium diisopropylamide gave deuteriodibutylstannane,
which appeared as a statistical mixture of dibutyltin
dihydride, deuteriodibutyltin hydride and dibutyltin
dideuteride (70% yield) (Scheme 2). Deuterium incor-
poration was higher than 95%. This mixture was
characterized by 119Sn NMR. Three resonances at
-204.0, -205.2, and -206.4 ppm, corresponding to a
statistical distribution of dibutyltin dihydride, deuterio-
dibutyltin hydride, and dibutyltin dideuteride, respec-
tively, were recorded.
The usefulness of this preparation of tin hydrides was
exemplified in the synthesis of tin hydride supported
reagents by the coupling of (hydridodibutylstannio)-
lithium with halogenated polystyrene, which allowed a
direct grafting of tin hydride units.24
The coupling worked equally well with ω-alkenyl
bromides and gave previously unreported ω-alkenyldi-
butyltins in good yield with two, three, or four methyl-
ene units between the tin and the double bond (Scheme
4). Heating the unsaturated hydrides led to mixtures
of cyclized and oligomerized compounds.
Sch em e 4
Sch em e 2
Bu2SnH2 + iPr2NLi -iPr NH8
2
Bu2SnHLi D O8 Bu2SnHD
2
Both experiments established the existence of a new
(organostannio)lithium, (hydridodibutylstannio)lithium.
In germanium21 and silicon22 chemistry, (hydridoger-
manio) and (hydridosilicio)lithiums have been reported
This cyclization process was studied in detail, as it
could be a new entry to stannacycloalkanes. Orga-
nostannyl radicals are well-known to add to olefinic
double bonds. Free-radical addition to carbon-carbon
double bonds can also occur intramolecularly, resulting
in cyclic products. Reactions with ω-alkenyldibutyltins
were run in sealed, degassed tubes in benzene using
azobisisobutyronitrile (AIBN) as initiator at 110 °C for
12 h (Scheme 5). With 4-pentenyldibutyltin, the only
(14) J ensen, F. R.; Davies, D. D. J . Am. Chem. Soc, 1971, 93, 4047.
San Filippo, J .; Silbermann, J . J . Am. Chem. Soc. 1981, 103, 5588.
Lee, K. W.; San Filippo, J . Organometallics 1982, 1, 1496. San Filippo,
J .; Silbermann, J . J . Am. Chem. Soc. 1982, 104, 2831. Smith, G. F.;
Kuivila, H. G.; Simon, R.; Sultan, L. J . Am. Chem. Soc. 1981, 103,
833. Lucas, C.; Santini, C.; Printz, M.; Basset, J . M.; Connil, M. F.;
J ousseaume, B. J . Organomet. Chem., in press.
(15) Gilman, H.; Mars, O. L.; Sim, S. Y. J . Org. Chem. 1962, 27,
4232.
Sch em e 5
(16) Tamborski, C.; Ford, F. E.; Soloski, E. J . J . Org. Chem. 1963,
28, 237.
(17) Still, W. C. J . Am. Chem. Soc. 1977, 99, 4836.
(18) Still, W. C. J . Am. Chem. Soc. 1978, 100, 1481.
(19) Van der Kerk, G. J . M.; Noltes, J . G.; Luijten, J . G. A. J . Appl.
Chem. 1957, 7, 366.
(20) J ousseaume, B.; Noiret, M.; Pereyre, A.; Saux, A. Organome-
tallics 1994, 13, 1034.
cyclization product was 1,1-dibutyl-1-stannacyclohex-
(21) Castel, A.; Rivie`re, P.; Satge´, J .; Ko, Y. H. Organometallics 1992,
9, 205.
(22) Roddick, D. M.; Heyn, R. H.; Tilley, T. D. Organometallics 1989,
8, 324.
(23) Matsuhashi, Y.; Tokitoh, N.; Okazaki, R.; Goto, M.; Nagase, S.
Organometallics 1993, 12, 1351.
(24) Dumartin, G.; Ruel, G.; Kharboutli, J .; Delmond, B.; Connil,
M. F.; J ousseaume, B.; Pereyre, M. Synlett 1994, 952.

Direct Access to Unsymmetrical Tin Hydrides
Organometallics, Vol. 15, No. 21, 1996 4471
ane,25 obtained in quantitative yield. No 1,1-dibutyl-
2-methyl-1-stannacyclopentane was detected. In con-
trast, 3-butenyldibutyltin hydride and 5-hexenyl-
dibutyltin hydride gave the corresponding cyclized
compounds in low yields only, and large quantities of
uncyclized tin hydrides were recovered.
these new hydrides are prepared according to the
classical way: introduction of the substituted organic
group via its Grignard or lithium reagent and trans-
formation of the resulting organotin halide to the tin
hydride. The use of (hydridodibutylstannio)lithium
provides substituted triorganotin hydrides directly from
diorganotin dihydrides and methoxylated halides, 1-bro-
mo-4-methoxybutane and 1-bromo-5,8-dioxanonane, in
good yields (Scheme 6).
The present results of the ring closure reaction of the
4-pentenyldibutylstannyl radical are clearly different
from those of the corresponding 5-hexenyl- and 4-pen-
tenylsilyl and 4-pentenylgermyl radicals. The 5-hexenyl
radical26 cyclizes to give a mixture of five- and six-
membered rings. This process can be driven to give the
five-membered ring by varying the reaction conditions.
The silylated27 and germylated28 analogs show a differ-
ent behavior: they lead in only low yield to mixtures of
five-and six-membered rings where the six-membered
ring predominates. The larger atomic radius of tin and
the longer tin-carbon bonds could favor the formation
of the six-membered ring by changing the stability of
both transition states and cyclic radicals. The revers-
ibility of organotin radical attack on olefins29 could also
favor the isomerization of the five-membered radical to
the six-membered radical, leading to the stereospecific
formation of the six-membered ring. In contrast, the
addition of silyl and germyl radicals is an irreversible
process. This method provides an interesting alterna-
tive to the known preparation of stannacyclohexanes,30
involving the decomposition of R,ω-distannylalkanes in
the presence of zinc chloride25 or the use of dimagnesium
halide derivatives31 which give these cyclic derivatives
together with oligomers and polymers.
Organotin hydrides with an organic group substituted
by polar substituents recently had interesting applica-
tions in organic synthesis. Tributyltin hydride is widely
used in preparative free-radical chemistry. However,
product isolation is sometimes difficult because com-
pounds containing tin formed in these reactions are not
always easily separated from the organic products. To
overcome this difficulty, several organotin hydrides
substituted by heteroatoms have been prepared. Three
organic groups can be substituted by ethylene glycol
ether units, as in tris[3-(2-methoxyethoxy)propyl]tin
hydride.7 This results in a high water solubility of the
tin hydride and allows an easy separation from organic
compounds simply by water extraction. When one
organic group is substituted by ethylene glycol ether
units, as in dibutyl(4,7,10-trioxaundecyl)tin hydride,9 or
by a pyridyl group, as in diphenyl(2-pyridylethyl)tin
hydride,10 the corresponding hydride can be separated
from organic compounds by chromatography on silica
gel. Substitution by heteroatoms is useful for reasons
other than solving separation problems. The introduc-
tion of a heteroatom can modify the reactivity of the
corresponding tin hydride. A dimethylamino group in
the γ-position from the metal increases the reactivity
of [2-(dimethylamino)phenyl]dimethyltin hydride,8 which
can serve as a selective nucleophilic hydride source or
as a radical reducing agent at room temperature. All
Sch em e 6
Br(CH2)m
2
2 n
Bu2SnHLi
(OCH CH ) OMe8
[MeO(CH2CH2O)n(CH2)m]Bu2SnH
m ) 4, n ) 0, yield 45%; m ) 4, n ) 1, yield 67%
While silicon-tin-bonded derivatives were described
as early as 1933,32 a similar bimetallic hydride with a
silicon-hydrogen bond was prepared only recently by
the coupling of (tributylstannio)lithium with chlorodi-
methylsilane.33 To our knowledge, no similar bimetallic
hydride with a tin-hydrogen bond has been prepared.
Bimetallic hydrides are of interest in radical reactions,
as it was shown that, with silicon hydrides, substitution
of an organic group on silicon by a trimethylsilyl group
weakens the silicon-hydride bond and thus enhances
the hydrogen transfer process in radical reactions. Tris-
(trimethylsilyl)silane is a valuable reagent in free-
radical processes.34 The coupling of (hydridodicyclo-
hexylstannio)lithium with chlorotriisopropylsilane gave
(triisopropylsilyl)dicyclohexyltin hydride (Scheme 7).
This reaction has also been used by others to prepare
(trimethylsilyl)dibutyltin hydride,35 which again dem-
onstrates the preparative utility of (hydridodiorga-
nostannio)lithiums.
Sch em e 7
iPr3SiCl
Cy (iPr Si)SnH
Cy2SnHLi
8
2
3
42%
In conclusion, it has been shown that (hydridodior-
ganostannio)lithiums can be easily prepared from vari-
ous diorganotin dihydrides and lithium diisopropyl-
amide. They are stable at low temperature and decom-
pose on heating to the corresponding triorganotin hy-
drides and poly(diorganotins). The coupling with func-
tional organic and organosilicon halides gives new
functional unsymmetrical triorganotin hydrides in a
particularly direct way.
Exp er im en ta l Section
All reactions were carried out under a nitrogen atmosphere.
Pentane, THF, and diethyl ether were distilled from sodium
benzophenone ketyl prior to use. Diisopropylamine was
distilled from calcium hydride. Dibutyl- and diphenyltin
hydrides were prepared by reduction of the corresponding
dichlorides by lithium aluminum hydride.36 1-Bromo-3-butene,
1-bromo-4-pentene, and 1-bromo-5-hexene were obtained from
(25) Bulten, E. J .; Budding, H. A. J . Organomet. Chem. 1976, 110,
167.
(26) Lamb, R. C.; Ayers, P. W.; Toney, M. K. J . Am. Chem. Soc. 1963,
85, 3483. J ulia, M. Acc. Chem. Res. 1971, 4, 386.
(27) Sakurai, H. In Free Radicals; Kochi, J ., Ed.; Wiley: New York,
1973; p 793.
(28) Mochida, K.; Asami, K. J . Organomet. Chem. 1982, 232, 13.
(29) Kuivila, H. G.; Sommer, R. J . Am. Chem. Soc. 1967, 89, 5616.
(30) Pant, B. C. J . Organomet. Chem. 1974, 66, 321.
(31) Davies, A.; Tse, M. W.; Kennedy, J . D.; McFarlane, W.; Ladd,
M. F. C.; Povey, D. C. J . Chem. Soc., Perkin Trans. 2 1981, 369.
(32) Kraus, C. A.; Eatough, H. J . Am. Chem. Soc. 1933, 55, 5003.
(33) Ikenaga, K.; Hiramatsu, K.; Nasaka, N.; Matsumodo, S. J . Org.
Chem. 1993, 58, 5045.
(34) Ballestri, M.; Chatgilialoglu, C.; Clark, K. B.; Griller, D.; Giese,
B.; Kopping, B. J . Org. Chem. 1991, 56, 678. Chatgilialoglu, C. Acc.
Chem. Res. 1992, 25, 188.
(35) Mitchell, T. Private communication.
(36) Creemers, H. M. J . C. Dissertation, University of Utrecht, 1967.

4472 Organometallics, Vol. 15, No. 21, 1996
Connil et al.
the corresponding ω-dibromoalkane.37 1-Bromo-4-methoxy-
butane and 1-bromo-5,8-dioxanonane were prepared according
to known procedures.38 1H NMR spectra and 13C NMR spectra
were taken on a Bruker AC-250 spectrometer (solvent C6D6,
internal reference Me4Si); 119Sn NMR spectra were recorded
on a Bruker AC-200 spectrometer (solvent C6D6, internal
reference Me4Sn). 119Sn-H and 119Sn-C coupling constants
(in Hz) are given in brackets.
3-Butenyldibutyltin hydride: yield 72%; bp 60 °C (0.001 mm);
1H NMR δ 0.74 (m, 12H), 1.15 (m, 4H), 1.41 (m, 4H), 1.87 (q,
2H, [48]), 4.52 (m, 1H), 4.79 (dd, 1H), 4.82 (dd, 1H), 5.55-
5.62 (m, 1H); 13C NMR δ 7.8 [335], 8.7 [343], 14.0, 27.6 [54],
30.4 [21], 32.1 [19], 113.4, 141.5; 119Sn NMR δ -86.2. Anal.
Calcd for C12H26Sn: C, 49.87; H, 9.07. Found: C, 48.42; H,
8.84. 4-Pentenyldibutyltin hydride: yield 67%; bp 60 °C (0.001
mm); 1H NMR δ 0.88 (m, 12H), 1.29 (m, 4H), 1.48 (m, 6H),
2.25 (q, 2H, [49]), 4.67 (m, 1H), 4.96 (dd, 1H), 5.02 (dd, 1H),
5.87 (m, 1H); 13C NMR δ 8.2 [337], 8.5 [341], 14.0, 27.7 [53],
30.4 [22], 31.1 [24], 38.7 [55], 114.8, 138.5; 119Sn NMR δ -87.2.
Anal. Calcd for C13H28Sn: C, 51.52; H, 9.31.Found: C, 50.87;
H, 8.95. 5-Hexenyldibutyltin hydride: yield 71%; bp 85 °C
Dicycloh exyltin Dih yd r id e. In a three-necked flask was
placed chlorotrimethylsilane (100 g, 0.92 mol), and tricyclo-
hexyltin hydroxide (40 g, 0.11 mol) was slowly added. The
mixture was heated at reflux for 12 h. Chlorotrimethylsilane
and hexamethyldisiloxane were distilled off, and tricyclohexyl-
tin chloride was recrystallized from petroleum ether (mp 129
°C, 29.7 g, 67%). A solution of bromine (8.7 g, 54 mmol) in 25
mL of chloroform was slowly added to tricyclohexyltin chloride
(22 g, 54 mmol) in 75 mL of chloroform. The mixture was
heated at reflux for 4 h. After evaporation of the solvent,
bromodicyclohexyltin chloride was recrystallized from ethanol
(mp 68 °C, 10.8 g, 50%). To a slurry of lithium aluminum
hydride (4.4 g, 110 mmol) in 125 mL of dry diethyl ether under
nitrogen at 0 °C was added a solution of bromodicyclohexyltin
chloride (28 g, 70 mmol). The mixture was refluxed for 2 h.
After addition of 100 mL of petroleum ether, the mixture was
hydrolyzed slowly with a saturated solution of ammonium
chloride. The resulting solution was dried over anhydrous
MgSO4 and evaporated under reduced pressure. Dicyclohexyl-
tin dihydride was purified by distillation (12.6 g, 63%, bp 110
1
(0.001 mm); H NMR δ 0.89 (m, 12H), 1.33 (m, 6H), 1.52 (m,
6H), 1.99 (q, 2H), 4.67 (m, 1H), 4.96 (dd, 1H), 5.02 (dd, 1H),
5.85 (m, 1H); 13C NMR δ 8.5 [338], 14.1, 27.7 [54], 30.6 [21],
33.9 [53], 34.0, 114.5, 138.9; 119Sn NMR δ -87.9. Anal. Calcd
for C14H30Sn: C, 53.03; H, 9.54. Found: C, 53.15; H, 9.09.
(4-Methoxybutyl)dibutyltin hydride: yield 45%; bp 90 °C (0.001
1
mm); H NMR δ 0.90 (m, 12H), 1.28-1.69 (m, 12H), 3.13 (s,
3H), 3.24 (t, 2H), 5.04 (m, 1H); 119Sn NMR δ -66.0. Anal.
Calcd for C13H30OSn: C, 48.63; H, 9.42. Found: C, 49.47; H,
9.07. (5,8-Dioxanonyl)dibutyltin hydride: yield 43%; bp 125
1
°C (0.001 mm); H NMR δ 0.88 (m, 12H), 1.32 (m, 4H), 1.60
(m, 8H), 3.14 (s, 3H), 3.33 (m, 6H), 4.96 (m, 1H); 13C NMR δ
8.3 [337], 13.8, 24.7 [25], 27.4 [55], 30.2 [29], 34.6 [44], 58.7,
70.5, 70.9, 72.4. Anal. Calcd for C15H34O2Sn: C, 49.34; H,
9.39. Found: C, 48.75; H, 9.02.
°C (10-4 mm)). 1H NMR δ 1.20-1.82 (m, 22H), 4.97 (s, 2H,
Cou plin g of (Hydr idodibu tylstan n io)lith iu m with P oly-
styr en e-Su p p or ted Ch lor id e. Dibutyltin dihydride (7.75 g,
33 mmol) was slowly added to a THF (20 mL)-hexane (12 mL)
solution of lithium diisopropylamide (30 mmol) at -70 °C.
After 30 min at -50 °C this solution was transferred into a
Schlenk tube containing 5 g (11.15 mmol of Cl) of poly[(4-
chlorobutyl)styrene] in 20 mL of THF, at -70 °C. The mixture
was warmed to -10 °C over 12 h. The polymer was washed
with THF (50 mL), THF/H2O (4/1; 20 mL), THF (5 × 40 mL),
and ethanol (3 × 40 mL) and was dried under vacuum. IR:
119
[1591]). 13C NMR: δ 25.6 [390], 27.4, 29.1 [56], 33.6 [17].
Sn NMR: δ -180.9.
-
Cou p lin g of (Hyd r id od ior ga n osta n n io)lith iu m s w ith
Or ga n ic Ha lid es. In a Schlenk tube under nitrogen, a
solution of n-butyllithium (8.4 mL, 21 mmol, 2.5 M in hexanes)
was added to a solution of diisopropylamine (2.12 g, 21 mmol)
in 50 mL of anhydrous THF, at 0 °C. After the mixture was
stirred for 15 min, the temperature was lowered to -70 °C
and the diorganotin dihydride (20 mmol) was added dropwise.
The mixture was stirred for 30 min at -50 °C and the halide
(20 mmol) added. The mixture was warmed to 0 °C, diluted
with 50 mL of petroleum ether, and hydrolyzed by dropwise
addition of water. The aqueous layer was separated and
extracted twice with 20 mL of petroleum ether. The organic
layer was washed with water and dried over anhydrous
MgSO4. The solvents were evaporated, and the corresponding
triorganotin hydrides were purified by distillation in a Kugel-
rohr apparatus. Methyldibutyltin hydride:39 yield 40%; bp 45
°C (0.1 mm); 1H NMR δ 0.05 (d, 3H, [45]), 0.90 (m, 10H), 1.41
(m, 4H), 4.88 (m, 1H); 13C NMR δ -13.7 [317], 8.3 [362], 13.7,
27.1 [132], 30.0 [53]. Anal. Calcd for C9H22Sn: C, 43.37; H,
8.83. Found: C, 42.12; H, 8.47. n-Propyldibutyltin hydride:
yield 60%; bp 60 °C (0.1 mm);1H NMR δ 0.9 (m, 15H), 1.30
(m, 4H), 1.55 (m, 6H), 4.85 (m, 1H); 13C NMR δ 8.5 [326], 11.2
[328], 13.7, 18.4 [52], 21.3 [22], 27.9 [52], 30.3 [22]; 119Sn NMR
νSn-H 1800 cm-1
. The poly[(4-(dibutylstannyl)butyl)styrene]
contained 1.4 mmol of Sn/g (% Sn 17.01).
Alk en yltin Hyd r id e Cycliza tion s. Alkenyldiorganotin
hydride (2 mmol), AIBN (5 mg), and heptane (35 mL) were
placed in a glass tube. The tube was sealed after degassing
and placed in an oven (110 °C, 12 h). After evaporation of
heptane the residue was analyzed by 119Sn NMR spectros-
copy: dibutylstannacyclopentane,25 δ 54.5; dibutylstannacy-
clohexane,25 δ -50.1; dibutylstannacycloheptane,25 δ 0.2. Di-
butylstannacyclohexane: 1H NMR δ 1.8-1.2 (m, 14H), 0.8-
1.05 (m, 14H); 13C NMR δ 8.9 [138], 9.0 [153], 13.8, 27.8 [56],
28.7 [27], 29.9 [20], 32.5 [43].
(Tr iisop r op ylsilyl)d icycloh exylsta n n a n e. In a Schlenk
tube under nitrogen, a solution of n-butyllithium (8.4 mL, 210
mmol, 2.5 M in hexanes) was added to a solution of diiso-
propylamine (2.12 g, 21 mmol) in 50 mL of anhydrous THF at
0 °C. After the mixture was stirred for 15 min, the temper-
ature was lowered to -70 °C and dicyclohexyltin dihydride
(5.74 g, 20 mmol) was added dropwise. The mixture was
stirred for 30 min at -50 °C and the halide (3.84 g, 20 mmol)
added. This mixture was warmed to 0 °C. Petroleum ether
(50 mL) was added, and then the mixture was hydrolyzed by
dropwise addition of water. The organic layer was separated,
the solvents were evaporated, and chromatography of the
residue under nitrogen (alumina, petroleum ether) gave the
desired product. Yield: 42%. HRMS: m/z 443.2153 (M - H),
calcd 443.2156. 1H NMR: δ 1.11 (m, 21H), 1.30-1.68 (m,
22H), 4.50 (s, 1H). 13C NMR; δ 14.2, 20.7, 26.8 [277], 27.6,
30.1 [53], 30.2 [53], 34.7 [14], 35.4 [14]. 119Sn NMR: δ -196.6.
δ -89.0. Anal. Calcd for
C11H26Sn: C, 47.69; H, 9.46.
Found: C, 47.12; H, 9.14. n-Propyldiphenyltin hydride: yield
1
50%; bp 110 °C (0.001 mm); H NMR δ 0.90 (t, 3H), 1.21 (t,
2H, [54]), 1.62 (m, 2H, [55]), 6.34 (m, 1H), 7.29 (m, 10H); 13C
NMR δ 13.1 [380], 18.3 [60], 20.8 [22], 128.8, 129.1 [11], 129.2,
137.5 [36]; 119Sn NMR δ -137. Anal. Calcd for C15H18Sn: C,
56.83; H, 5.72. Found: C, 56.38;H, 5.27. n-Propyldicyclo-
1
hexyltin hydride: yield 63%; bp 120 °C (0.001 mm); H NMR
δ 0.93 (m, 2H), 1.02 (t, 3H), 1.25-1.90 (m, 24H), 5.15 (s, 1H);
13C NMR δ 10.0 [309], 19.2 [51], 21.8 [22], 25.8 [362], 27.4,
29.2 [54], 33.2 [16], 33.3 [16]; 119Sn NMR δ -87.9. Anal. Calcd
for C15H30Sn: C, 54.75; H, 9.19. Found: C, 54.98; H, 8.95.
(37) Kraus, G. A.; Landgrebe, K. Synthesis 1984, 885.
(38) Kirrmann, A.; Hamaide, N. Bull. Soc. Chim. Fr. 1957, 789.
(39) Martin-Lauda, I.; De Pablos, F.; Marr, I. L. Anal. Proc. 1989,
26, 16.
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