Russian Journal of General Chemistry, Vol. 75, No. 2, 2005, pp. 319 320. Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005,
pp. 349 350.
Original Russian Text Copyright
2005 by Martynov, Amosova.
LETTERS
TO THE EDITOR
Formation of a Geminal Vinyl Selenide on Selenostannylation
of Phenylacetylene under the Action of Stannic Chloride
A. V. Martynov and S. V. Amosova
Favorskii Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
Received July 28, 2004
Earlier we found that selanylstannanes RSeSnR3
in the presence of SnCl4 add to terminal acetylenes
to form 1,2-bis(organylselanyl)ethenes [1] that regio-
selectively convert into organyl 1-alkyl selenides upon
heating at 180 C [2].
tion [3, 7 10], or in palladium(0)-catalyzed addition
to phenylacetylene of heteroatomic compounds
PhSeXMe3 (X = Si, Ge) and Me3GeSiMe2Ph [12].
However, unlike the adduct of trimethylsilyl phenyl
selenide with phenylacetylene 12], that is resistant to
alkali and converts into phenyl 1-phenylvinyl selenide
under the action of Bu4NF only, our proposed stan-
nylethenyl selenide MeSeCPh= CHSn(SeMe)3 under-
goes destannylation under the action of a dilute solu-
tion of KOH.
Further study of the reaction of selanylstannanes
with acetylenes gave an unexpected result. It was
found that treatment of the mixture resulting from the
reaction of phenylacetylene and triethyl(methylsela-
nyl)stannane (I) under the conditions described in [1]
with 5% KOH rather than water provides methyl
1-phenylvinyl selenide (II). In the absence of stannic
chloride, the reaction fails.
Methyl 1-phenylvinyl selenide (II). A mixture of
0.88 g of triethyl(methylselanyl)stannane and 1.30 g
of tin tetrachloride was stirred for 30 min at 78 C
under argon in 2 ml of chloroform, after which 0.40
g of phenylacetylene was added. The resulting mix-
ture was stirred for 6 h at room temperature, diluted
with 30 ml of chloroform, and treated with 200 ml of
5% KOH. The chloroform layer was separated, the
aqueous-alkaline layer was treated with ether, and the
combined were dried with CaCl2. The solvents were
removed to leave 0.62 g of a mixture containing,
1) SnCl4;
2) KOH/H2O
RSeSnEt3 + CH CR
RSeR =CH2.
I
II
R = Me, R = Ph.
Evidence for the formation of vinyl selenide II
comes from the 1H NMR spectrum that contains
characteristic signals of vicinal protons at 5.77 and
26 ppm (2JHH 0.58 Hz).
1
according to H NMR and GLC data, selenide II
(26%), as well as starting selanylstannane I (9.5%,
GLC data), chlorotriethylstannane (42%), and phenyl-
Taking account of the reaction scheme in [1] we
can explain the resulting data in terms of regioselec-
tive addition to phenylacetylene of the intermediate
tetra(methylselanyl)stannane (MeSe)4Sn which was
1
acetylene (6%). Selenide II. H NMR spectrum,
,
ppm: 7.57 7.66 m, 7.45 7.35 m (5H, C6H5), 5.75 d
2
(1H, cis-CPh=CH, JHH 0.58 Hz), 5.25 d (1H, trans-
2
2
CPh=CH, JHH 0.58 Hz), 2.12 s (3H, MeSe, JSeH
17 Hz) {published data [13]: 7.20 7.56 m (5H, C6H5),
5.68 s (1H, cis-CPh=CH), 5.20 s (1H, trans-CPh=CH),
2.01 s (3H, MeSe)}. 77Se NMR spectrum, Se, ppm:
223. Mass spectrum, m/z (80Se): [M]+ 198, [M
1
detected in the reaction mixture by H NMR [1]. Al-
kaline hydrolysis of the adduct formed leads to
geminal vinyl selenide II. Treatment of the reaction
mixture with water gives rise to dimethyl diselenide
whose reaction with the adduct provides 1,2-bis(me-
thylselanyl)-1-phenylethene [1].
Me]+ 183, [M
MeSe]+ 103.
1
Thus, the regioselectivity of the addition of sela-
nylstannanes II to phenylacetylene is similar to that
observed both in nucleophilic additions of arenetho-
lates [3 10] and selenolates [11] to terminal acety-
lenes, which occur mostly as anti-Markovnikov addi-
The H and 77Se NMR spectra were measured in
CDCl3 solutions on a Bruker DPX-400 spectrometer
at 400 MHz (1H) and 76.3 MHz (77Se). The mass
spectrum was obtained on an HP-5971A instrument,
ionizing energy 70 eV.
1070-3632/05/7502-0319 2005 Pleiades Publishing, Inc.
Martynov
