Synthesis of alkoxystannanes by reactions of O-(organylstannyl) carbamates with alcohols

Article abstract of DOI:10.1023/B:RUCB.0000037867.28725.b6

Reactions of O-(organylstannyl) carbamates with alcohols afford alkoxystannanes and proceed most completely on heating in an excess of alcohol. The reactions provide a new approach to the synthesis of difficultly accessible alkoxystannanes.

Full text of DOI:10.1023/B:RUCB.0000037867.28725.b6

936
Russian Chemical Bulletin, International Edition, Vol. 53, No. 4, pp. 936—938, April, 2004
Brief Communications
Synthesis of alkoxystannanes by reactions of
Oꢀ(organylstannyl) carbamates with alcohols
N. V. Komarov, N. A. Ryzhkova,ꢀ and A. A. Andreev
Kuban State University,
149 ul. Stavropol´skaya, 350040 Krasnodar, Russian Federation.
Fax: +7 (861 2) 69 9502. Eꢀmail: silan@chem.kubsu.ru
Reactions of Oꢀ(organylstannyl) carbamates with alcohols afford alkoxystannanes and
proceed most completely on heating in an excess of alcohol. The reactions provide a new
approach to the synthesis of difficultly accessible alkoxystannanes.
Key words: organotin carbamates, Oꢀorganylstannyl N,Nꢀdialkylcarbamates, organylꢀ
alkoxystannanes, diorganyldialkoxystannanes.
Earlier,1—5 we have described the reactions of
OHꢀacids, such as alkanols. The starting Oꢀdi(tri)organylꢀ
Oꢀorganostannyl N,Nꢀdialkylcarbamates with alkꢀ1ꢀynes,
βꢀdicarbonyl compounds, secondary amines, sodium
borohydride, and organochlorosilanes. The reactivity of
organotin carbamates differs from that of alkyltin carbꢀ
oxylates due to the influence of the amino group on carꢀ
boxyl. Based on this fact, new approaches to the conꢀ
struction of the Sn—C, Sn—H, Sn—O, etc. bonds were
proposed, which hold promise for organometallic syntheꢀ
sis. We have also developed new procedures for the prepaꢀ
ration of organotin carbamates, which makes these comꢀ
pounds more accessible.3,6
stannyl carbamates were prepared by the reactions of Oꢀtriꢀ
methylsilyl carbamates with organotin oxides and hexaꢀ
organyldistannoxanes6 (Eqs (1) and (2), respectively).
Compound 3b was synthesized in the present study for the
first time.
In the present study, we examined the reactions of
organotin carbamates with alcohols as an alternative apꢀ
proach to the synthesis of alkoxyorganylstannanes. Reacꢀ
tions with aliphatic alcohols are untypical of organotin
carboxylates. However, the structural features of organotin
derivatives of N,Nꢀdialkylcarbamic acids as well as the
data on their reactivity obtained earlier1—5 give grounds
to expect that these compounds would react with weak
NR12 = NEt2 (1a, 3a, 3b), N(CH2)5 (1b, 3c);
R
2 = Et (2a, 3a), Bu (2b, 3b, 3c)
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 898—900, April, 2004.
1066ꢀ5285/04/5304ꢀ0936 © 2004 Plenum Publishing Corporation

Synthesis of alkoxystannanes
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 4, April, 2004
937
Results and Discussion
Alkoxystannanes 5 were identified by elemental analyꢀ
sis and IR spectroscopy as well as by comparing their
physicochemical parameters with the published data
(Table 2).
The IR spectra of the compounds synthesized have a
broad absorption band at 1075—1070 cm–1 correspondꢀ
ing to C—O stretching vibrations.
The reaction under consideration can be used as a
convenient procedure for the preparation of various
organylalkoxystannanes. This method is free from the
known drawbacks, in particular, there is no need to sepaꢀ
rate finely dispersed precipitates of sodium halides,
which presents difficulties, in the case of the synthesis
of organylalkoxystannanes from sodium alkoxides and
alkyltin halides12 or to use difficultly accessible stannylated
amines.13
We found that Oꢀorganylstannyl carbamates 3 effiꢀ
ciently react with alcohols 4 on heating above 100 °C.
Apparently, the reaction proceeds through the mechansim
of nucleophilic substitution at the Sn atom to form the
corresponding organylalkoxystannanes 5 and N,Nꢀdialkylꢀ
carbamic acids, which decompose under the conditions
of reaction (3) with elimination of secondary amine
and CO2.
Experimental
n = 1 (3a—c, 5a,b,d—f,g,h), 2 (3d, 5c,i);
R
R
1 = Et (3a, 5a,b,d,e,g), Bun (3b,c, 5c,f,h,i);
3 = Pr (4a, 5d), Bun (4b, 5a,f,i), Bui (4с, 5е), But (4d, 5e),
The solvents and starting compounds were thoroughly dried
and purified by distillation.
The IR spectra were recorded on an IKSꢀ29 spectrometer
(LOMO) in the frequency range of 4200—400 cm–1 (accuracy
was +5 cm–1).
The 1H NMR spectra were measured on a Tesla BS 587a
instrument (80 MHz) in CDCl3 with HMDS as the internal
standard.
OꢀTrimethylsilyl carbamates 1a,b were synthesized by carꢀ
boxylation of trimethylchlorosilane in the presence of the correꢀ
sponding secondary amines in anhydrous benzene according to
a known procedure.12
Carbamates 3a,c,d were prepared from silyl carbamates 1
according to a procedure described in our earlier study.6
Tributylstannyl N,Nꢀdiethylcarbamate (3b). A mixture of carꢀ
bamate 1a (3.4 g, 0.018 mol) and hexabutylstannoxane (5.36 g,
0.009 mol) was heated at 160—180 °C (oil bath) for 0.5 h.
Vacuum distillation afforded compound 3b in a yield of 5.33 g
(73%), b.p. 129—130 °C/2 Torr, nD 1.4748, d4 1.1233.
Found (%): C, 50.68; H, 8.88; N, 3.71; Sn, 29.73. C17H37NO2Sn.
Calculated (%): C, 50.27; H, 9.18; N, 3.45; Sn, 29.22. IR (in
a thin layer), ν/cm–1: 1628 (C=O). 1H NMR, δ: 3.14
(m, >N—CH).
Bn (4e, 5h), cycloꢀC6H11 (4f, 5b,c);
NR22 = NEt2 (3a,b,d), N(CH2)5 (3c)
The yields of triorganylalkoxystannanes may be as high
as 95%. Diorganyldialkoxystannanes were prepared in
somewhat lower yields (60—75%) due to their lower therꢀ
mal stability and partial decomposition in the course of
vacuum distillation.
Primary, secondary, and tertiary alcohols differ slightly
in reactivity. The temperature is of decisive importance in
these reactions. The use of higherꢀboiling alcohols makes
it possible to decrease the reaction time and prepare the
reaction products in higher yields. The use of an excess of
alcohol also increases the conversion of the starting
Oꢀorganylstannyl carbamates. The reaction conditions and
the yields of the products are given in Table 1.
20
20
Organylalkoxystannanes are colorless liquids, which
are readily hydrolyzed with water, including atmospheric
moisture, and can be involved in various transformations
at the Sn—O bond.
Table 1. Conditions of the synthesis of alkoxystannanes 5a—i
Reaction product 5
Yield
(%)
Starting
Oꢀstannyl carbamate
Starting
alcohol
Reaction conditions
Molar
T/°C
τ/h
ratio 3 : 4
BunOSnEt3 (5a)
cycloꢀC6H11OSnEt3 (5b)
(cycloꢀC6H11O)2SnBu2 (5c) 69
PrnOSnEt3 (5d)
BuiOSnEt3 (5e)
BunOSnBu3 (5f)
ButOSnEt3 (5g)
BnOSnBu3 (5h)
(BunO)2SnBu2 (5i)
86
84
Et3SnOC(O)NEt2 (3a)
BunOH (4b)
cycloꢀC6H11OH (4f)
4f
15 : 80
10 : 90
14 : 30
13 : 126
4 : 12
9.5 : 31
11 : 110
3.2 : 16
7.2 : 72
100
120
120
100
110
130
90
0.5
1.0
0.5
1.0
0.5
0.75
1.0
1.0
0.25
3a
Bu2Sn[OC(O)NEt2]2 (3d)
58
70
93
34
95
60
3a
3a
PrnOH (4a)
BuiOH (4c)
4b
Bu3SnOC(O)NEt2 (3b)
3a
ButOH (4d)
BnOH (4e)
4b
Bu3SnOC(O)N(CH2)5 (3c)
120
100
3d

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Russ.Chem.Bull., Int.Ed., Vol. 53, No. 4, April, 2004
Komarov et al.
Table 2. Physicochemical parameters of alkoxystannanes 5a—i
20
20
Comꢀ
pound
M.p./°C
(p/Torr)
nD
d4
Found
Calculated
Published data
(%)
20
20
B.p./°C
(p/Torr)
nD
d4
Referꢀ
ence
C
H
Sn
5a
5b
5c
95—97 (7)
81—82 (2)
128 (0.5)
1.4680
1.4913
1.4812
1.1922
1.2208
1.1138
42.70
43.05
47.95
47.25
55.12
55.70
—
42.85
43.05
—
9.04
8.67
8.79
8.59
9.22
9.35
—
8.90
8.67
—
42.14
42.54
38.26
38.91
27.17
27.52
—
42.38
42.54
—
—
120—124 (5)
—
—
—
1.4923
—
—
—
7
8
5d
5e
76 (6)
76—77 (1)
1.4687
1.4660
1.2258
1.1007
83—84 (8)
—
1.4660 1.2019
—
—
5f
5g
139—141 (4)
113 (36)
1.4670
1.4630
1.0854
1.1632
124—128 (3)
132—135
(112)
1.4688
1.4672
—
—
9
10
—
—
—
5h
5i
138—140 (1)
132—134 (1)
1.5106
1.4699
1.1449
1.2159
57.24
57.45
50.85
50.68
9.02
8.63
9.41
9.56
30.03
29.88
31.09
31.30
—
—
—
160 (3)
1.2056
11
Butoxytriethylstannane (5a). Carbamate 3a (5 g, 15.5 mmol)
3. N. A. Boldyreva, N. V. Komarov, and A. A. Andreev,
Zh. Obshch. Khim., 1987, 57, 2801 [J. Gen. Chem. USSR,
1987, 57 (Engl. Transl.)].
4. N. A. Boldyreva, A. A. Andreev, and N. V. Komarov,
Zh. Obshch. Khim., 1988, 58, 1181 [J. Gen. Chem. USSR,
1988, 58 (Engl. Transl.)].
5. N. V. Komarov, N. A. Ryzhkova, and A. A. Andreev, Izv.
Akad. Nauk, Ser. Khim., 1994, 313 [Russ. Chem. Bull., 1994,
43, 293 (Engl. Transl.)].
and nꢀbutyl alcohol (6 g, 0.08 mol) were placed in an apparatus
for vacuum distillation. The reaction mixture was heated at
100 °C (temperature of an oil bath) for 0.5 h. After removal of a
lowꢀboiling fraction by vacuum distillation, compound 5a was
isolated in a yield of 3.72 g (86%), b.p. 95—97 °C/7 Torr,
20
20
d4 1.1922, nD 1.4680. Found (%): C, 42.70; H, 9.04;
Sn, 42.14. C10H24OSn. Calculated (%): C, 43.05; H, 8.67;
Sn, 42.54. IR, ν/cm–1: 1070 (Sn—O—C).
Cyclohexyloxytriethylstannane (5b). A mixture of carbamate
3a (3.2 g, 0.01 mol) and cyclohexanol (10 g, 0.09 mol) was
heated at 120 °C for 1 h on an oil bath with protection from
atmospheric moisture. Excess alcohol was removed by vacuum
distillation and compound 5b was obtained in a yield of 2.56 g
6. N. A. Boldyreva, N. V. Komarov, and A. A. Andreev,
Zh. Obshch. Khim., 1988, 58, 1932 [J. Gen. Chem. USSR,
1988, 58 (Engl. Transl.)].
7. G. A. Razuvaev and N. S. Vyazankin, Zh. Obshch. Khim.,
1960, 30, 2498 [J. Gen. Chem. USSR, 1960, 30 (Engl. Transl.)].
8. I. F. Lutsenko and S. V. Ponomarev, Zh. Obshch. Khim.,
1961, 31, 2025 [J. Gen. Chem. USSR, 1961, 31 (Engl. Transl.)].
9. R. K. Ingam, C. D. Rosenberg, and M. Gilman, Chem. Rev.,
1960, 60, 510.
10. G. A. Razuvaev, N. S. Vyazankin, and E. S. D´yachkovskaya,
Zh. Obshch. Khim., 1962, 32, 2161 [J. Gen. Chem. USSR,
1962, 32 (Engl. Transl.)].
11. C. I. Zhivukhin, E. D. Dudikova, and TerꢀSarkisyan,
Zh. Obshch. Khim., 1962, 32, 3059 [J. Gen. Chem. USSR,
1962, 32 (Engl. Transl.)].
20
20
(84%), b.p. 81—82 °C/2 Torr, d4 1.2208, nD 1.4913 (cf. lit.
20
data7: b.p. 120—124 °C/5 Torr, nD 1.4923).
Dicyclohexyloxydibutylstannane (5c) was prepared analoꢀ
gously by heating a mixture of dibutylstannyl bis(N,Nꢀdiethylꢀ
carbamate) 3d (6.57 g, 0.014 mol) and cyclohexanol (3.31 g,
0.03 mol) at 100—120 °C (temperature of an oil bath) for 0.5 h
under argon. Vacuum distillation afforded compound 5c in a
20
yield of 4.15 g (68.7%), b.p. 128 °C/0.5 Torr, d4 1.1138,
20
nD 1.4812. Found (%): C, 55.12; H, 9.22; Sn, 27.17.
C
20H40O2Sn. Calculated (%): C, 55.70; H, 9.35; Sn, 27.52. IR,
ν/cm–1: 1075 (Sn—O—C).
12. D. Knausz, A. Meszticzky, L. Szakacs, B. Csakvari, and
K. Ujszaszy, J. Organomet. Chem., 1983, 256, 11.
13. J. C. Pommier and M. Pereyre, in Organotin Compounds:
New Chemistry and Applications, Ed. J. J. Zuckerman, Adv.
Chem. Ser., American Chemical Society, Washington, 1976,
No. 157, p. 82.
References
1. A. A. Andreev, N. A. Boldyreva, and N. V. Komarov,
Zh. Obshch. Khim., 1986, 56, 1664 [J. Gen. Chem. USSR,
1986, 56 (Engl. Transl.)].
14. J. D. Kennedy, W. McFarlane, P. J. Smith, R. F. M. White,
and L. Smith, J. Chem. Soc., Perkin Trans. 2, 1973, 1785.
2. N. A. Boldyreva, N. V. Komarov, and A. A. Andreev,
Zh. Obshch. Khim., 1988, 58, 1179 [J. Gen. Chem. USSR,
1988, 58 (Engl. Transl.)].
Received April 12, 2003;
in revised form December 3, 2003