New Method of Synthesis of Phosphinobenzenes and 1,2-Diphosphinobenzenes [3]

Full text of DOI:10.1023/A:1024725012685

Russian Journal of General Chemistry, Vol. 73, No. 2, 2003, pp. 319 320. Translated from Zhurnal Obshchei Khimii, Vol. 73, No. 2, 2003,
pp. 343 344.
Original Russian Text Copyright
2003 by Tverdomed, Dogadina, Ionin.
LETTERS
TO THE EDITOR
New Method of Synthesis of Phosphinobenzenes
and 1,2-Diphosphinobenzenes
S. N. Tverdomed, A. V. Dogadina, and B. I. Ionin
St. Petersburg State Institute of Technology, St. Petersburg, Russia
Received October 28, 2002
Reactions leading to formation of a carbon phos-
phorus bond, especially of two such bonds in the
same molecule, are of special interest in coordination
and organoelement chemistry [1]. It is very attractable
to find synthetic routes to 1,2-disubstituted benzene
derivatives capable of forming chelate complexes with
transition metals [2 4]. Earlier we showed that ace-
tylenic phosphonates and -diphosphonates readily
react with donor 1,3-alkadienes to form carbocyclic
compounds whose subsequent aromatization gives rise
to ortho-substituted benzenephosphonates and ortho-
benzenediphosphonates [5]. In this communication
we present a general method for synthesis of benzene-
phosphines and 1,2-benzenediphosphines.
Benzenediphosphonates Ia and Ib and 2-chloroben-
zenephosphonate Ic are hardly reduced with lithium
aluminum hydride. We succeeded in the reduction
using LiALH4 in the presence of AlCl3 in diethyl
ether to obtain substituted benzene-1,2-diphosphines
IIa and IIb and 2-chlorobenzenephosphine Ic.
R2
R1
R2
R1
(MeO)2(O)P
(MeO)2(O)P
R2
R1
H2P
X
(MeO)2(O)P
Cl
SiHCl3/C6H6
yield 60%
LiAlH4/(C2H5)2O
yield 50 55%
Ib
IIa IIc
Ib, Ic
R1 = R2 = CH3, X = PH2 (a), Cl (b); R1 = CH3, R2 = H, X = PH2 (c).
1
Trichlorosilane in benzene reduces dimethyl 2-
chloro-4,5-dimethylbenzenephosphonate (Ib) to phos-
103 106 C (1 mm). H NMR spectrum, , ppm :
3
1
7.34 m (2H, JHP 4.8 Hz), 4.01 d.d (4H, JHP 207.5,
phine IIb with a higher yield, and the product is purer. 4JHP 22.8 Hz), 2.21 s (6H). 13C NMR spectrum,
,
C
2
ppm: 136.93 d (C3,6, JCP 9.1 Hz), 136.73 d (C4,5,
3JCP 10.2 Hz), 130.99 d.d (C1,2, JCP 6.6 Hz), 19.07 s
1
4,5-Dimethyl-1,2-diphosphinobenzene (IIa). To a
suspension of 0.15 mol of LiALH4 in 100 ml of ab-
solute ether cooled to 70 C, we added quickly with
vigorous stirring 0.06 mol of anhydrous AlCl3. The
suspension was cooled to 60 C, and a solution of
0.03 mol of tetramethyl 4,5-dimethylbenzene-1,2-di-
phosphonate (Ia) in 50 ml of ether was added drop-
wise. The reaction mixture was stirred for 4 h at room
temperature and 1 h under reflux, cooled to 30 C,
and 0.15 mol of water distilled under argon was added
dropwise. The mixture was allowed to warm to room
temperature, then it was refluxed for 2 h, filtered, and
the filtrate was dried over Na2SO4 and evaporated.
The residue was distilled in vacuo. Yield 55%, bp
(C7,8). 31P NMR spectrum, P, ppm: 126.11 m.
2-Chloro-4,5-dimethyl-1-phospinobenzene (IIb).
a. Prepared similarly to IIa with halved reagent
amounts. Yield 53%.
b. To a solution of 0.1 mol of SiHCl3 in 70 ml of
anhydrous benzene cooled to 0 C we added quickly
a solution of 0.03 mol of dimethyl 2-chloro-4,5-di-
methylbenzene-1-phosphonate (Ib) in 50 ml of ben-
zene. The solution was refluxed with stirring for 12 h,
then cooled to 0 C, and a solution of 0.3 mol of
NaOH in 100 ml of water distilled under argon was
added to it dropwise. The reaction mixture was kept
1070-3632/03/7302-0319$25.00 2002 MAIK Nauka/Interperiodica

320
TVERDOMED et al.
at 60 C until the amorphous precipitate had dissolved,
the organic layer was separated, and the aqueous layer
was twice extracted with benzene. The organic ex-
tracts were combined, dried over Na2SO4, the solvent
was removed, and the residue was distilled in vacuo.
The synthesis of phospines and all experiments
were performed under argon (special purity grade).
1
The H, 13C and 31P NMR spectra of solutions were
registered on a Varian XL200 spectrometer, operating
frequencies 200.05 (1H), 50.328 (13C) and 81 MHz
(31P), solvents C6D6 and CDCl3. The chemical shifts
1
Yield 60%, bp 98 102 C (1 mm). H NMR spectrum,
3
4
, ppm: 7.29 d (1H, JHP 6.2 Hz), 7.13 d (1H, JHP
1
are given relatively to internal TMS (13C, H) and
1
2.7 Hz), 3.98 d (2H, JHP 209.0 Hz ), 2.20 s (6H).
external 85% H3PO4 (31P).
13C NMR spectrum, C, ppm: 138.39 s (C4), 136.25 d
(C3, JCP 10.8 Hz), 134.90 d (C2, JCP 4.6 Hz),
3
2
134.77 d (C5, JCP 7.9 Hz), 129.62 s (C6), 126.64 d
3
REFERENCES
(C1, 1JCP 9.6 Hz), 18.99 s (C7), 18.60 s (C8). 31P NMR
spectrum, P, ppm: 129.19 s.
1. Schlosser, M. and Keller, H., Justus Liebigs Ann. Chem.,
1995, 1587.
3,4-Diphosphinotoluene (IIc) was prepared si-
milarly to IIa. Yield 50%, bp 86 90 C (1 mm). H
1
2. Kyba, E.P. and Steven, P.R., Tetrahedron Lett., 1981,
3
3
NMR spectrum, , ppm: 7.44 d.d (1H, JHP 9.6, JHH
vol. 22, no. 20, p. 1875.
3
3
3.0 Hz), 7.38 d (1H, JHH 3.7 Hz), 7.02 d (1H, JHP
8.0 Hz), 4.04 d.d (4H, 1JHP 208.1, 4JHP 6.0 Hz), 2.31 s
(3H). 13C NMR spectrum, C2, ppm: 138.07 d (C5, 3JCP
3. Kyba, E.P. and Liu Shiuh-Tzung, Organometallics,
1983, vol. 2, no. 12, p. 1877.
3
4.7 Hz), 135.89 d.d (C3, JCP 3.9, JCP 3.5 Hz),
4. Seyferth, D. and Paetsch, J.D.H., J. Org. Chem., 1969,
135.40 d.d (C6, JCP 3.9, JCP 13.6 Hz), 134.42 d.d
2
3
vol. 34, no. 5, p. 1483.
(C1, 1JCP 15.1, 2JCP 6.8 Hz), 130.29 d.d (C2, 1JCP 14.9,
2JCP 6.9 Hz), 128.98 d (C4, 3JCP 5.4 Hz), 20.70 s (C7).
5. Tverdomed, S.N., Dogadina, A.V., and Ionin, B.I., Zh.
Obshch. Khim., 2001, vol. 71, no. 11, p. 1926.
31P NMR spectrum, P, ppm: 124.47 m.
6. Issleib, K., Liessring, F., and Meyer, H., Tetrahedron
Lett., 1981, no. 22, p. 4475.
The earlier described unsubstituted diphosphino-
benzene [6] was prepared similarly.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 2 2003