878
IVANOVA et al.
O
H
1) Ph C
;
R1
R2
O
2) HCl/H2O
NaNH2/THF
Ia Id
P
IIa, IIb + IIIa IIId
(2)
R3
A
An even stronger anion-destabilizing effect is
characteristic by alkyl and phenylalkyl radicals, be-
cause of which we could involve triethyl- and tris-
(2-phenylethyl)phosphine oxides in reaction (1).
E-1,2-Diphenylethene (IIa), yield 88, 70, and
62% from phosphine oxides Ia, Ic, and Id, respec-
tively. The constants and spectral data of ethene IIa
agree with those reported in [1, 14].
These results complement the known data [13]
concerning the determining role of the nature of sub-
stituents in triorganylphosphine oxides in their de-
protonation under conditions of the Wittig Horner
reaction. The synthetic material presented in this work
considerably extends the range of application of the
Wittig Horner reaction for stereoselective synthesis
of substituted stylbenes and suggest that this strategy
can be succssfully extended to hetero analogs of
benzyl halides having substituents in the heteroring.
E-1-(5-Chloro-2-thienyl)-2-phenylethene (IIb),
1
yield 71%, mp 66-68 C. H NMR spectrum, , ppm:
3
6.79 s, 6.80 s (2H, H3, H4), 6.78 d (1H, H , JHH
3
15.8 Hz), 7.06 d (1H, H , JHH 15.8 Hz), 7.24 t (1H,
Hp), 7.33 t (2H, Hm), 7.43 d (2H, Ho). The H and H
1
signals were assigned on the basis of the 1H H
NOEZSY spectrum which showed a cross peak cor-
responding to H Ho coupling. Since the signals of
H3 and H4 protons and one of the components of the
1
H
doublet in the H NMR spectrum overlap, the
H,C-correlation (HMQC) experiment was performed
EXPERIMENTAL
for signal assignment. 13C NMR spectrum, C, ppm:
124.03 (C ), 128.02 (cross peak with the proton at
6.80, C3, or C4), 129.02 (Co), 129.40 (cross peak with
the proton at 6.79, C3, or C4), 130.54 (Cp), 131.22
The H and 31P NMR spectra were recorded on a
1
Bruker DPX-400 spectrometer in CDCl3 against in-
ternal HMDS and external 85% phosporic acid, res-
pectively. The IR spectra were recorded on a Specord
75-IR spectrometer.
(C ), 131.43 (Cm). Found, %: C 64.83; H 4.08; Cl
16.11; S 14.39. C12H9ClS. Calculated, %: C 65.30; H
4.11; Cl 16.06; S 14.53.
Synthesis of 1-organyl-2-phenylethenes IIa, IIb
and diorganylphosphinic acids IIIa IIId (general
procedure. Sodium amide, 6.6 mmol, was added to a
solution of 2.2 mmol of triorganylphosphine oxide in
40 ml of THF heated to 58 60 C. The resulting mix-
ture was stirred for 1 h at 58 60 C and, after
2.2 mmol of benzaldehyde had been added, refluxed
for 1 h, cooled, diluted with 35 ml of water, and
extracted with ether (3 10 ml). The ethereal extract
was washed with water (2 8 ml), dried over potas-
sium carbonate, the ether was removed, and the
residue was dried in a vacuum to obtain (E)-1-orga-
nyl-2-phenylethene IIa, IIb. The aqueous layers were
combined and acidified with 2 N HCl to pH 2 3. The
precipitate that formed was successively washed with
water, ethanol, ether, and dried in a vacuum to obtain
diorganylphosphinic acid IIIa, IIIb. In the case of
formation of water-soluble acids, the aqueous fraction
was acidified and extracted with chloroform to obtain
acid IIIc, IIId. Acid IIId was not isolated pure, and
is probably present in the aqueous fraction among four
organophosphorus compounds ( P 49.48, 46.20, 45.36,
and 38.09 ppm, integral intensity ratio the 31P NMR
signals 20:48:10:22).
Dibenzylphosphinic acid (IIIa), yield 65%, mp
189 190 C (from ethanol) (published data [15]: mp
1
191 C). H NMR spectrum, , ppm: 2.85 d (4H, CH2,
2JPH 16.9 Hz), 7.21 m (10H, C6H5), 9.02 s (1H, OH).
31P NMR spectrum, P, ppm: 49.48. Found, %: C
67.92; H 6.13; P 12.71. C14H15O2P. Calculated, %: C
68.29; H 6.14; P 12.58.
Bis[(5-chloro-2-thienyl)methyl]phosphinic acid
1
(IIIb), yield 39%, mp 168 170 C (from ethanol). H
2
NMR spectrum, , ppm: 3.16 d (4H, CH2P, JPH
3
16.3 Hz), 6.77 t (2H, H3), 6.99 d (2H, H4, JHH
4.0 Hz). 31P NMR spectrum, P, ppm: 46.6. Found,
%: C 36.83; H 2.73; Cl 21.68; P 9.56; S 19.43.
C10H9Cl2O2PS2. Calculated, %: C 36.71; H 2.77; Cl
21.67; P 9.47; S 19.60.
Diethylphosphinic acid (IIIc), yield 48%, bp
194 195 C (21 mm) [16]. 1H NMR spectrum, , ppm:
1.05 t (6H, CH3), 1.81 m (4H, CH2), 9.08 s (1H, OH).
31P NMR spectrum, P, ppm: 51.8. Found, %: C
39.87; H 9.23; P 25.66. C4H11O2P. Calculated, %: C
39.35, H 9.08, P 25.37.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 6 2003