Wurtz-type reductive coupling reaction of primary alkyl iodides and haloorganotins in cosolvent/H2O(NH4Cl)/Zn media as a route to mixed alkylstannanes and hexaalkyldistannanes

Article abstract of DOI:10.1016/S0022-328X(00)00388-0

Mixed tetra-alkylstannanes R₃SnR′ (R = Et, n-Pr, n-Bu and R′= Me, Et, n-Pr, n-Bu, n-Pent) and R₂SnR′₂ (R = n-Bu and R′ = Me, Et, n-Pr, n-Bu) can be easily prepared in a one-pot synthesis via coupling reaction of alkyl iodides R′I with R₃SnX (X = Cl, I) and R₂SnCl₂ compounds in cosolvent-H₂O(NH₄Cl) medium mediated by zinc dust. Coupling also occurs with (Bu₃Sn)₂O. It has been verified that reactions are possible only with primary alkyl iodides; with secondary alkyl iodides the coupling reaction fails. When alkyl chlorides and bromides are used ditin compounds are obtained instead of the unsymmetrical tetra-alkylstannanes. This represents a route to hexaalkyldistannanes.

Full text of DOI:10.1016/S0022-328X(00)00388-0

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 612 (2000) 78–84
Wurtz-type reductive coupling reaction of primary alkyl iodides
and haloorganotins in cosolvent/H2O(NH4Cl)/Zn media as a route
to mixed alkylstannanes and hexaalkyldistannanes
Daniele Marton *, Massimo Tari
Dipartimento di Chimica Inorganica, Metallorganica ed Analitica, Uni6ersita` di Pado6a, Via Marzolo 1, I-35131 Padua, Italy
Received 28 February 2000; received in revised form 14 June 2000
Abstract
Mixed tetra-alkylstannanes R3SnR% (R=Et, n-Pr, n-Bu and R%=Me, Et, n-Pr, n-Bu, n-Pent) and R2SnR%2 (R=n-Bu and
R%=Me, Et, n-Pr, n-Bu) can be easily prepared in a one-pot synthesis via coupling reaction of alkyl iodides R%I with R3SnX
(X=Cl, I) and R2SnCl2 compounds in cosolvent–H2O(NH4Cl) medium mediated by zinc dust. Coupling also occurs with
(Bu3Sn)2O. It has been verified that reactions are possible only with primary alkyl iodides; with secondary alkyl iodides the
coupling reaction fails. When alkyl chlorides and bromides are used ditin compounds are obtained instead of the unsymmetrical
tetra-alkylstannanes. This represents a route to hexaalkyldistannanes. © 2000 Elsevier Science B.V. All rights reserved.
Keywords: Alkyltin; Coupling; Distannane
1. Introduction
This methodology has been now recognized to be
useful for coupling reactions between saturated alkyl
iodides and organotin halides in forming SnꢀCalkyl
bonds.
The Wurtz-type reductive coupling reaction mediated
by zinc powder, depicted in Eq. (1),
THF/H O(NH Cl)/Zn
2
4
Thus, the work deals with the preparation of mixed
nR%Br+R4−nSnClnꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢁ R4−nSnR%
(1)
n
alkyltin derivatives of the type R3SnR% or R2SnR%
room temperature, stirring
2
(R%=allyl, crotyl, allenyl, benzyl groups; n=1, 2)
(R=Et, n-Pr, n-Bu; R%=Me, Et, n-Pr, n-Bu, n-Pent),
as well as of hexaalkylditins R3SnSnR3 (R=Et, n-Pr,
n-Bu).
has been successfully employed when R%=allyl, crotyl,
allenyl and benzyl groups [1–4].
The stereochemical pathways of these reactions, to-
gether with those dealing with the allylation of alde-
2. Results and discussion
hydes [5], seem to be determined by the structure of the
−
’
radical anions [R%Br] adsorbed on the zinc particles,
2.1. Coupling reactions of tri- and diorganotins and
alkyl iodides
not on the geometry of the organic halides, cosolvents
or salt [3,5].
This procedure has been adopted in SnꢀSn forming
Table 1 shows the results obtained from reactions of
mono- or dichloro alkyltins R3SnCl and R2SnCl2 (R=
Et, n-Pr, n-Bu) and tributyltin oxide, (Bu3Sn)2O, with
primary alkyl iodides R%I, with R%=Me, Et, n-Pr, n-Bu
and n-Pent.
bond reactions [3], as well as depicted in Eq. (2):
THF/H O(NH Cl)/Zn
R3SnClꢀꢀꢀꢀꢀꢀꢀ2ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢁ R3SnꢀSnR3
(2)
4
room temperature, stirring
(R=phenyl, o-, m-, p-toly group)
The feasibility of these reactions is the same as those
previously reported for the formation of the SnꢀCallyl
bond [1] where both organotin chlorides and oxide have
been used. Nevertheless, in the present cases, a different
* Corresponding author. Tel.: +39-49-8275221; fax: +39-49-
8275179.
E-mail address: marton@chin.unipd.it (D. Marton).
0022-328X/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00388-0

Table 1
Preparation of mixed alkylstannanes from tri- and diorganotin derivatives and alkyl iodides in H2O(NH4Cl)/THF/Zn medium
Entry no.
Reagent
Amount of
Reaction time c
(h)
Product
Amount of product (g
(yield%))
H2O b/THF (ml)
Organotin
Amount (g
(mmol))
Alkyl iodide
Amount (g
(mmol))
Amount Zn (g
(mmol)) a
1
2
Et3SnCl
Et3SnCl
7.3 (30.1)
7.4 (30.5)
MeI
n-BuI
17.1 (120.5)
22.6 (119.9)
8.0 (122.4)
8.5 (130.2)
50/25
50/25
1.5
1.0
Et3SnMe
Et3Sn(n-Bu)
4.9 (74)
6.8 (85)
3
4
5
n-Pr3SnCl
n-Pr3SnCl
n-Pr3SnCl
5.6 (19.8)
6.0 (21.0)
5.2 (18.4)
MeI
EtI
n-PrI
8.5 (59.9)
9.5 (60.6)
10.1 (60.6)
4.0 (61.2)
4.2 (61.8)
4.2 (61.8)
50/25
50/25
50/25
0.5
1.0
1.0
n-Pr3SnMe
n-Pr3SnEt
n-Pr3Sn(n-Pr)
3.9 (75)
4.7 (82)
4.2 (79)
/
6
7
8
9
n-Bu3SnCl
n-Bu3SnCl
n-Bu3SnCl
n-Bu3SnCl
n-Bu3SnCl
9.8 (30.2)
9.8 (30.2)
9.8 (30.2)
9.8 (30.2)
9.9 (30.5)
MeI
EtI
n-PrI
n-BuI e
n-PentI e
17.1 (120.5)
18.7 (120.0)
20.2 (120.0)
22.1 (120.0)
23.8 (120.3)
7.9 (121.2)
8.1 (123.7)
8.0 (122.4)
8.0 (122.4)
8.5 (129.9)
50/25
50/25
50/25
50/25
50/25
1.0
1.5
1.5
3.0
5.0
n-Bu3SnMe
n-Bu3SnEt
n-Bu3Sn(n-Pr)
n-Bu3Sn(n-Bu)
n-Bu3Sn(n-Pent)
7.7 (84)
7.6 (79)
6.8 (68) d
4.8 (46) d
4.8 (44) d
10
11
12
13
14
(n-Bu3Sn)2O
(n-Bu3Sn)2O
(n-Bu3Sn)2O
(n-Bu3Sn)2O
11.9 (20.0)
11.9 (20.0)
11.9 (20.0)
11.9 (20.0)
MeI
EtI
n-BuI
n-PentI
22.7 (160.0)
24.9 (160.0)
29.4 (160.0)
31.7 (160.0)
10.5 (160.0)
10.5 (160.0)
10.5 (160.0)
10.5 (160.0)
100/50
100/50
100/50
100/50
1.5
1.5
5.5
4.5
n-Bu3SnMe
n-Bu3SnEt
n-Bu3Sn(n-Bu)
n-Bu3Sn(n-Pent)
11.9 (88)
12.8 (80)
6.9 (50) d
5.4 (37) d
612
15
16
17
18
19
n-Bu2SnCl2
n-Bu2SnCl2
n-Bu2SnCl2
n-Bu2SnCl2
n-Bu2SnCl2
4.5 (14.9)
9.2 (30.3)
9.1 (30.0)
9.1 (30.0)
9.1 (30.0)
MeI
MeI
EtI
n-PrI
n-BuI
17.1 (120.5)
34.1 (240.1)
39.2 (251.0)
40.8 (240.0)
44.2 (240.0)
7.8 (119.6)
15.8 (241.9)
16.4 (250.2)
15.7 (240.0)
15.7 (249.0)
50/25
100/50
100/50
100/50
100/50
1.0
1.0
1.0
3.5
3.5
n-Bu2SnMe2
n-Bu2SnMe2
n-Bu2SnEt2
2.5 (64)
5.0 (62)
4.8 (55)
5.1 (52) d
0
n-Bu2Sn(n-Bu)2
7
n-Bu2Sn(n-Pent)2 4.4 (42) d
a Zinc dust,B10 mm.
b Deionized water saturated with NH4Cl.
c This time has been evaluated looking at the disappearance of the 119Sn-NMR or GLC signals of the starting organotin. In some cases, two identical gas-chromatographic profiles in two
consecutive GLC tests marked the end of the reaction.
d Yield was calculated with reference to the product obtained by elution through a chromatographic column (see Section 4).
e In this case, after 1.5 h, a further addition of 15 mmol of alkyl iodide was carried out.

Table 2
Halogen and solvent effect a
Entry no.
Reagent
Cosolvent
Reaction time c
(h)
Product
Amount of product (g (yield%))
/
Organotin
Amount (g
(mmol))
Alkyl iodide
Amount (g
(mmol))
Amount Zn (g
(mmol)) b
20
21
22
23
24
25
n-Bu3SnI
n-Bu3SnCl
n-Bu3SnI
n-Bu3SnCl
n-Bu3SnI
n-Bu3SnCl
12.5 (30.0)
9.4 (29.0)
12.5 (30.0)
11.1 (34.2)
12.5 (30.0)
10.0 (30.8)
MeI
MeI
MeI
MeI
n-BuI
n-BuI
17.0 (120.0)
17.1 (120.5)
17.3 (120.7)
17.3 (120.7)
22.1 (120.0)
22.3 (120.0)
8.0 (122.4)
8.1(123.1)
8.0 (122.4)
8.0 (122.4)
8.0 (122.4)
8.1 (123.1)
THF
THF
Cyclohexane 1.0
Cyclohexane 3.0
THF
THF
1.0
1.0
n-Bu3SnMe
n-Bu3SnMe
n-Bu3SnMe
n-Bu3SnMe
n-Bu3Sn(n-Bu)
n-Bu3Sn(n-Bu)
7.8 (85)
7.3 (82)
7.1 (77)
5.4 (52) d
7.3 (70)
5.2 (48) d
1.0
3.5
a Comparison between the results obtained using tributyltin chloride and tributyltin iodide in coupling reactions with alkyl iodides in H2O(NH4Cl)/cosolvent/Zn medium. All runs were
performed using 50 ml of deionized water saturated with NH4Cl and 25 ml of cosolvent.
612
b Zinc dust,B10 mm.
(
c This time has been evaluated looking at the disappearance of the 119Sn-NMR or GLC signals of the starting organotin. In some cases, two identical gas-chromatographic profiles in two
consecutive GLC tests marked the end of the reaction.
d Yield was calculated with reference to the product obtained by elution through a chromatographic column (see Section 4).
7

D. Marton, M. Tari / Journal of Organometallic Chemistry 612 (2000) 78–84
81
Table 3
Preparation of hexaalkyldistannanes from trialkyltin halides in H2O(NH4Cl)/THF/Zn medium a
Entry no.
Reagent
Reaction time c (h) Amount of product (g (yield%))
Amount organotin (g (mmol)) Amount Zn (g
(mmol)) b
26
27
28
29
30
Et3SnCl
10.9 (45.0)
n-Pr3SnCl
11.8 (41.3)
n-Bu3SnCl
9,8 (30.0)
n-Bu3SnI
25.0 (60.0)
5.8 (90.0)
5.5 (83.6)
3.9 (60.2)
7.8 (120.0)
7.8 (120.0)
17
24
22
20
22
(Et3Sn)2
5.0 (54)
(n-Pr3Sn)2
6.0 (58)
(n-Bu3Sn)2
3.9 (45)
(n-Bu3Sn)2
8.1 (47)
d
n-Pr3SnCl, n-Bu3SnCl
8.5 (30.0) 9.8 (30.0)
(n-Pr3Sn)2, (n-Pr3)Sn-Sn(n-Bu3), (n-Bu3Sn)2
2.2 (15) 4.5 (28) 2.3 (13)
a All runs were performed under nitrogen flow using 50 ml of deionized water saturated with NH4Cl and 25 ml of THF.
b Zinc dust,B10 mm.
c This time has been evaluated looking at the disappearance of the 119Sn-NMR or GLC signals of the starting organotin halide.
d The composition of the mixture of the three distannanes was calculated by integration of the corresponding 119Sn-NMR resonance lines.
behavior is observed, because coupling is only possible
when organic iodides are employed: the use of alkyl
chorides and bromides give rise to ditin compounds (see
below).
are highly reactive compounds in Zn/THF/H2O
(NH4Cl) medium: the main reaction is the reduction of
the iodides by zinc and, under these conditions, n-
Bu3SnCl is converted in n-Bu3SnI (61–87%). The for-
mation of n-Bu3SnI is due to an exchange reaction
between n-Bu3SnCl and the iodide ions1. By contrast, in
the runs performed with i-PrBr or n-BuCl, the reduc-
Yields fall in the range 42–88%, and many reactions
are characterized by high exothermicity (entries 1–7,
11, 12 and 15–17); the end of the reactions is reached in
0.5–5.5 h. These reactions seem to be affected by steric
hindrance from both R and R% groups; the larger is the
bulkiness of the alkyl group the lower is the yield: e.g.
see on passing from methyl to n-pentyl iodides (entries
6–10), or from Et3SnCl to n-Bu3SnCl (entries 2, 5 and
9). This behavior is similar to that found for the
nucleophilic electrochemical alkylation of Bu3SnCl with
MeI, EtI and n-PrI to form Bu3SnMe, Bu3SnEt and
Bu3SnPr [6]: the corresponding yields are 100, 82 and
40% respectively. Steric effects have also been found to
be important in related coupling reactions between
R3SnCl derivatives (R=Et, n-Pr, n-Bu) and benzyl
bromides [3]. In the coupling reactions between
Bu2SnCl2 and alkyl iodides (see Table 1 entries 15–19),
steric effects are also operating.
tion of organic halides has been never observed and the
−
’
main reaction is the coupling of [Bu3SnX]
Bu3SnX to form hexabutylditin.
with
2.2. Halogen and sol6ent effects
Table 2 shows the results obtained using Bu3SnI in
comparison with those obtained with Bu3SnCl. Com-
parison must be made inside the pair of runs of entries
20–21, 22–23 and 24–25 respectively, where the same
cosolvent has been employed.
Yields are in the range 48–85% and the best results
have been obtained, independent of the employed co-
solvent (THF or cyclohexane), when n-Bu3SnI is used
instead of n-Bu3SnCl. This result may be explained by
two factors: (i) owing to the lesser polarity of the SnꢀI
bond with respect of that of SnꢀCl bond [11], n-Bu3SnI
will be present in the organic phase at higher concentra-
tions than n-Bu3SnCl, so that the trapping of the
Reactions performed using (n-Bu3Sn)2O yield the
same results as those obtained using (n-Bu3SnCl (com-
pare entries 6–10 with entries 11–14).
The small amount of organic solvent used, the short
reactions time and the fairly good yields obtained in
many cases, have the adopted procedure offers some
advantages with respect to those based for instance on
the Grignard reagent [7,8] or on the use of organostan-
nylmetal [9] and organostannyl hydrides substrates [7].
Attempts to carry out coupling reactions between
n-Bu3SnCl and secondary organic iodides RI (R=i-
propyl, sec-butyl, cyclohexyl) or i-PrBr or n-BuCl (a
primary organic halide) failed. The secondary iodides
1 The formation of Bu3SnI has been verified to occur when
Bu3SnCl is allowed to react in H2O/THF in the presence of the sole
NH4I. On the contrary, a metathetic reaction was not observed when
equimolar amounts of Bu3SnCl and organic iodide were allowed to
react in H2O(NH4Cl)/THF medium in the absence of zinc. Indeed, an
exchange reaction between Bu3SnCl and RI in an organic medium is
only possible at high temperature in the presence of catalysts [10].

82
D. Marton, M. Tari / Journal of Organometallic Chemistry 612 (2000) 78–84
−
’
radicals ions [R%I]
by n-Bu3SnI species will be
reaction observed is the reduction of the organic iodides
favored2; (II) the iodide is a better leaving group than
chloride in nucleophilic substitution reactions [12].
(Eqs. (3) and (4)). When organic bromides or chlorides
are used, the main reaction is the formation of ditin
compounds (Eq. (5)). Formation of SnꢀCalkyl bonds
may be carried out only by employing primary alkyl
2.3. Preparation of hexa-alkyldistannanes
iodides.
−
’
So far, this methodology has been applied in the past
[3,4] only for the preparation of hexaaryldistannanes,
because these compounds are fairly stable in water and
towards the oxygen of the air. The same conditions can
not be adopted for the preparation of hexaalkyldistan-
nanes, because, as it is known, these are oxidized in air
to give the oxide, (R3Sn)2O [13]. We succeeded in
preparing some hexa-alkyldistannanes (see Table 3) by
working under nitrogen atmosphere.
Even though the yields are not high (45–58%), this
very simple methodology may be preferred to other
procedures that give higher yields but need long work-
up [14–16].
The formation of radical ions [R%X]
on a metal
surface seems to be characterized by two reaction steps
[17]: (i) a molecular absorption occurs with the initial
attachment of the halogen atom to the metal surface;
(ii) the adsorbed halide can simply desorb (released
unchanged) or undergo dissociation of the carbon-halo-
gen bond. Thus, the formation of these ion radicals
depends both on the nature of the organic group, which
can allocate the unpaired electron or upon the tendency
of the carbon-halogen bond to dissociate. This is in the
order IꢀBr\Cl, as it can be formulated on taking
into account for the electron affinities of the organic
halides [18]. Analogously, the formation of the ion
radicals [R3SnX] still depends upon the tendency of
−
’
the tinꢀhalogen bond to dissociate. This is in the order
R3SnI\R3SnBr\R3SnCl as it can be argue from the
electrochemical potential reduction of these substrates,
which are more negative in the order R3SnCl\
R3SnBr\R3SnI [19].
3. General comments
Exhaustive explanation of the obtained results re-
quires recognition that competitive reactions occur into
the system together with the main reaction (Eq. (1)).
The following reactions deal with the reduction (medi-
ated by zinc) of alkyl iodides to alkanes3.
4. Experimental
H3O++[R%I]−Zn+“R%ꢀH+ZnI++H2O
H2O+[R%I]−Zn+“R%ꢀH+ZnI++HO−
(3)
(4)
All manipulations were carried out under air atmo-
sphere at room temperature. Nitrogen atmosphere was
only used for preparations of distannanes. THF was
distilled before use; other solvents, salts and zinc dust
(B10 mm), commercially available, were used as
received.
Tripropyltin chloride, tributyltin chloride, tributyltin
iodide and bis(tributyltin) oxide, commercially available
(Aldrich), were distilled under vacuum before use. Tri-
ethyltin chloride was prepared by redistribution reac-
tion between tetraethylstannane and tin tetrachloride
[20]. Bu2SnCl2 was recrystallized before use. All the
alkyl iodides, commercially available, were employed as
received.
Reaction 4 is especially important for secondary and
tertiary alkyl halides which react with water more
rapidly than their primary counterparts [17].
Finally, the coupling reaction:
R3SnX+[R3SnX]−Zn+“R3SnꢀSnR3+ZnX2
(5)
dealing with the formation of the tin-tin bond [2–5]
must be considered.
Only when primary alkyl iodides are used, the trap-
−
’
ping of the radical ions [R%I] by the organotin species
occurs to form of SnꢀC bond in competition with
reactions 3 and 4. Since the coupling reaction seems to
be greatly affected by steric effects, the reduction of the
organic iodides (Eqs. (3) and (4)) became prevalent as
the steric hindrance of both R and R% groups increases
(see Table 1, compare entry 2 with entries 9 and entries
6–10). Indeed, with secondary organic iodides the sole
Boiling points, infrared spectra [21], as well as 13C-
and 119Sn-NMR [8,22–26] were in agreement with
those reported in literature. Infrared spectra were regis-
tered as pure liquid (CsI optics) using a Perkin–Elmer
599B spectrophotometer. The NMR spectra, registered
as pure liquid using Me4Sn and Me4Si as external and
internal standard respectively, were obtained with a
JEOL FX90Q instrument Fourier Transform NMR
2 For our previous mechanistic considerations about these reactions
see Ref. [2].
spectrometer. GLC analyses were made using
a
3 Reactions 3 and 4 are prevalent with respect to both dimerization
and dismutation reactions. Indeed, the reaction between the sole
n-pentyl iodide and zinc in H2O(NH4Cl)/THF medium gives rise only
n-pentane with traces of n-decane. Formation of 3,4-dimethyloctane
is not observed.
Perkin–Elmer gas-chromatograph model 8310
equipped with a flame-ionization detector (DB1 non-
polar column, 15 m, 0,25 mm i.d., Ti=200°C, Td=
320°C, Tc=80–300°C, 10°C min−1, nitrogen as carrier

D. Marton, M. Tari / Journal of Organometallic Chemistry 612 (2000) 78–84
83
gas at 10 psi, 1/35 split). Additional GC–MS character-
ization of the products was made using a Carlo Erba
gas-chromatograph model HRGC 800 EC-WAX
column, 30 m, 0.25 mm i.d., Ti=250°C, helium as
carrier gas at 1 ml min−1, 1/30 split) combined with a
Fisons mass spectrometer model 800 equipped with an
electron impact ionization source (−70 eV) and a
quadrupole mass analyzer.
The progress of the reactions was monitored by
means of 119Sn-NMR or GLC. The complete disap-
pearance of the related signals (or peaks) or their
standing at a constant value marked the end of the
reactions. In such a way, we have had the possibility to
make a rough comparison between the rates of the
various processes here considered.
air, the system was always maintained under nitrogen
flow. Reactions required 17–22 h for completion. After
this time, the unreacted zinc was removed by filtration
and the aqueous phase was extracted with n-pentane.
Removal of the solvent left a slurry residue, which was
distilled under vacuum to afford pure ditin compounds.
Entry 30 of Table 3 deals with the attempt to prepare
the mixed ditin Pr3SnSnBu3. Its 119Sn- and 13C-NMR
chemical shifts are as follows:
Acknowledgements
4.1. Preparation of R3SnR% and R2SnR% compounds
2
(entries 1–25)
The authors are grateful for financial support from
the Ministero dell’ Universita` e della Ricerca Scientifica
e Tecnologica (MURST, Rome). They thank Professor
Giuseppe Tagliavini, University of Padua, for helpful
suggestions and for critical reading of the manuscript.
In a round bottom two-necked flask (100 ml)
equipped with a condenser and dropping funnel and
magnetic stirrer, the appropriate alkyl tin halide was
added at room temperature into the system organic
cosolvent/H2O (NH4Cl saturated)/Zn dust (the quanti-
ties are given in Table 1). Under stirring, the appropri-
ate alkyl iodide (generally in 1:1 stoichiometric ratio
with respect to the zinc) was added dropwise over
about 15 min, a rate sufficient to maintain a gentle
reflux due to the exothermicity of many reactions. At
the end of the reaction, the unreacted zinc was filtered
off and the aqueous phase was extracted three times
with n-pentane (10 ml each). The separated organic
layer was washed with saturated aqueous NaCl solution
and dried over MgSO4. Removal of the solvent left a
crude oil, which was distilled under vacuum to afford
the pure alkyltin compound. In a few cases (see Table
1, entries 8–10, 13,14, 18 and 19) the distilled product
contained unreacted starting organotin halide. A fur-
ther purification by elution on a chromatographic
column (22 cm length, filled with silica gel 70–230
mesh) using n-hexane as eluent was carried out to
ensure a pure compound. Yields, listed in Table 1, were
calculated from the amount of pure compound.
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(1992) 2961.
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13 (1992) 906.
[3] D. Marton, U. Russo, D. Stivanello, G. Tagliavini, P. Ganis,
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[4] D. Marton, G. Tagliavini, in: V.G. Kumar Das (Ed.), Main
Group Element and Their Compounds, Narosa, New Delhi,
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4.2. Preparation of hexa-alkyldistannanes (entries
26–30)
In a round bottom two-necked flask (100 ml), an
appropriate amount of zinc powder was added under
stirring to 25 ml of THF and 50 ml of a solution
saturated with NH4Cl, kept under nitrogen atmosphere.
Then, the trialkyltin halide (the quantities are indicated
in Table 3) was added. In order to avoid the presence of

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D. Marton, M. Tari / Journal of Organometallic Chemistry 612 (2000) 78–84
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