Russian Journal of General Chemistry, Vol. 72, No. 7, 2002, p. 1141. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 7, 2002,
p. 1220.
Original Russian Text Copyright
2002 by Trofimov, Sukhov, Gusarova, Malysheva, Mal’kina.
LETTERS
TO THE EDITOR
An Unexpected Redox Reaction
between Tris(Z-phenylethenyl)phosphine
and 4-Hydroxy-4-methyl-2-pentynonitrile
B. A. Trofimov, B. G. Sukhov, N. K. Gusarova, S. F. Malysheva, and A. G. Mal’kina
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received July 18, 2001
Tris(Z-phenylethenyl)phosphine I [1] is readily
oxidized with 4-hydroxy-4-methyl-2-pentynonitrile II
into tris(Z-phenylethenyl)phosphine oxide III (yield
98%). In the process, hydroxyalkyne II is reduced to
4-methylpenta-2,3-dienonitrile IV (yield 74%).
Allene IV was also prepared in 75% yield from II
and triphenylphosphine. Thus, the reaction is appar-
ently common for tertiary phosphines and can be used
for mild reduction of cyanoacetylenic alcohols into
allenes.
Reaction of tris(Z-phenylethenyl)phosphine with
4-hydroxy-4-methyl-2-pentynonitrile. A solution of
0.510 g of I and 0.147 g of II in 2 ml of diethyl ether
was kept at room temperature for 3 h. The crystalline
precipitate was filtered off and washed with pentane;
0.5 g (94%) of III was obtained. The product was
identified using an authentic sample [1]. From the
ether and pentane filtrates, the solvents were removed,
and the residue was vacuum-fractionated; allene IV
was collected in a cooled trap. Yield 0.18 g (78%).
IR spectrum, , cm : 2222, 1969, 781. 1H NMR spec-
trum, , ppm: 1.06 d (6H, Me), 4.39 septet (1H,
=CHCN). These characteristics are in agreement with
published data [2].
1
Apparently, the reaction starts with nucleophilic
addition of I across the triple bond in II to form zwit-
terion V, which transforms into zwitterion VI by in-
tramolecular proton transfer. Cyclization of VII into
phosphetane VII and its subsequent decomposition
yield phosphine oxide III and allene IV.
In the reaction with triphenylphosphine under
similar conditions, the yields of triphenylphosphine
oxide and allene IV were 95 and 75%, respectively.
The IR spectra were taken on a Specord IR-75
spectrometer (KBr pellets or thin films). The 1H
and 31P NMR spectra were recorded on a Bruker
DPX-400 spectrometer (400 MHz) in CDCl3, internal
reference HMDS.
REFERENCES
1. Trofimov, B.A., Malysheva, S.F., Rakhmatulina, T.N.,
Gusarov, A.V., and Gusarova, N.K., Zh. Obshch. Khim.,
1991, vol. 61, no. 3, p. 1955.
2. Greaves, P.M., Landor, S.R., and Laws, D.R.J.,
J. Chem. Soc. (C), 1968, no. 3, p. 291.
1070-3632/02/7207-1141$27.00 2002 MAIK Nauka/Interperiodica