Reactions of elemental phoshorus and phosphine with electrophiles in superbasic systems: XIX. Formation of the C-P bond with participation of elemental phosphorus under microwave assistance

Article abstract of DOI:10.1134/S1070363207030140

Microwave irradiation facilitates phosphorylation of aryl methyl chlorides and styrene with red phosphorus in the presence of strong bases and increases the yield of the main products, tertiary phosphine oxides. Nauka/Interperiodica 2007.

Full text of DOI:10.1134/S1070363207030140

ISSN 1070-3632, Russian Journal of General Chemistry, 2007, Vol. 77, No. 3, pp. 415 420.
Pleiades Publishing, Ltd., 2007.
Original Russian Text S.F. Malysheva, N.K. Gusarova, V.A. Kuimov, B.G. Sukhov, A.A. Kudryavtsev, O.G. Sinyashin, Yu.G. Budnikova, Z.P. Pai,
A.G. Tolstikov, B.A. Trofimov, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 3, pp. 449 454.
Reactions of Elemental Phosphorus and Phosphine
with Electrophiles in Superbasic Systems:
XIX.1 Formation of the C P Bond with Participation
of Elemental Phosphorus under Microwave Assistance
S. F. Malyshevaa, N. K. Gusarovaa, V. A. Kuimova, B. G. Sukhova,
A. A. Kudryavtseva, O. G. Sinyashinb, Yu. G. Budnikovab,
Z. P. Paic, A. G. Tolstikovc, and B. A. Trofimova
a Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul Favorskogo 1, Irkutsk, 664033 Russia
b Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center,
Russian Academy of Sciences, Kazan, Tatarstan, Russia
c Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Received December 19, 2006
Abstract Microwave irradiation facilitates phosphorylation of aryl methyl chlorides and styrene with red
phosphorus in the presence of strong bases and increases the yield of the main products, tertiary phosphine
oxides.
DOI: 10.1134/S1070363207030140
Synthesis of organophosphorus compounds based
on elemental phosphorus is actively developing. It
attracts the attention of researchers by its evident
simplicity and technological feasibility [1 6]. Sub-
stantial contribution to elaboration of the method of
direct phosphorylation of organic substrates was made
by new approach to activation of elemental phos-
phorus based on the use of heterogeneous superbasic
catalytic media and reagents [7 12] as well as by elec-
trochemical transformation of elemental phosphorus
under the action of organic and organometallic com-
pounds [6, 13, 14]. It opened nontraditional approaches
to formation of the P C, P O, P N bonds and al-
lowed to realize direct reactions of elemental phos-
phorus with readily available organic compounds such
as alkenes, acetylenes, alkene oxides, organyl halides,
aldehydes, etc. Further activation of the electrophile
phosphorylation processes with elemental phosphorus
by ultrasound [9, 15, 16] and radiation assistance [1,
4, 17] was also reported. At the same time, the data
on microwave activation of these reactions are limited
to a short communication on the reaction of red phos-
phorus with vinyl pyridines in the system KOH DMSO
(an increase of the reaction rate was observed [18]).
In the present paper we report on new data of suc-
cessful application of microwave irradiation for acti-
vation of phosphorylation of electrophiles, in parti-
cular, of aryl methyl chlorides and styrene, with red
phosphorus in the presence of strong bases. As the
source of microwave irradiation we used a domestic
microwave oven (90, 360 and 600 Wt).
The experiments showed that 10 min action of
microwave irradiation of 90 Wt power on the system
red phosphorus benzyl chloride KOH dioxane H2O
phase transfer catalyst (benzyl triethylammonium
chloride) allows one to prepare tribenzyl phosphine
oxide (I) in high yield (78%) along with small amounts
of the products of incomplete benzylation: secondary
phosphine oxide (II), benzylphosphonous (III), ben-
zylphosphonic (IV) and dibenzylphosphinic (V) acids
in total yield of 15%; the conversion of phosphorus
and benzyl chloride were 65 and 85%, respectively
(see the table, no. 1). Phosphinic acids III V were
isolated after acidification of the reaction mixture.
Heating of the above reagents to 90 95 C for 3 h
without microwave assistance was reported to lead to
full conversion of red phosphorus and benzyl chloride
with the formation of tribenzyl and dibenzyl phos-
phine oxides in 61 and 12%, respectively [19] (see the
table, no. 2).
1
For communication XVIII, see [1].
415

416
MALYSHEVA et al.
Upon the increase of the microwave oven power to
tion of the phosphorus crystal lattice under the action
of microwave irradiation, that increases the phos-
phorus-centered nucleophiles concentration in the
reaction medium and, therefore, the yield of the
products of their incomplete benzylation.
360 and 600 Wt with simultaneous decrease of dura-
tion of reaction (1) to 2.5 5 min the yield of the ter-
tiary phosphine oxide I is slightly reduced but the
total yield of compounds II V is increased (see the
table, nos. 3 5). This is due to more effective destruc-
O
O
Cl
KOH/H2O
MW
P
P
+
+ Pn
H
I
II
+
(1)
+
+
O
O
O
P
P
P
OK
KO
OK
H
KO
HCl/H2O
+
+
O
O
O
P
P
P
OH
H
OH
HO
HO
III
IV
V
1-Chloromethylnaphthalene is known to react with
red phosphorus in the system KOH dioxane H2O
benzyl triethylammonium chloride upon heating (90
95 C, 3 h) [1] to afford tris(1-naphthylmethyl)phos-
phine oxide (VI), bis(1-naphthylmethyl)phosphine
oxide (VII), (1-naphthylmethyl)phosphonous (VIII),
and bis(1-naphthylmethyl)phosphinic acids in 69, 18,
6 and 7% yield, respectively (see the table, no. 6).
Microwave irradiation (90 Wt) of these reagents
allows one to reduce the reaction time to 10min, that
is, by more than one order of magnitude, and to obtain
compounds VI VIII in 68, 8, and 17% yield, respec-
tively (see the table, no. 7).
microwave irradiation (600 Wt, 4 min) and results
mainly in tris(2-phenylethyl)phosphine oxide (IX) in
83% yield, the conversion of styrene and red phos-
phorus being 88 and 100%, respectively (see the table,
no. 9). Small amounts of bis(2-phenylethyl)phosphine
oxide (X), 2-phenylethyl phosphinous (XI) and bis-
(2-phenylethyl) phosphinic (XII) acids are also
formed under these conditions (see the table, no. 9).
The use of microwave irradiation of lower power
(360 Wt), in spite of some increase of the reaction
time (6 min), results in a decrease of the yield of
tertiary phosphine oxide IX to 69% (see the table,
no. 10). At the same time, without microwave assis-
tance, upon heating of the above reaction mixture to
90 95 C for 3 h the effectiveness of phosphorylation
Phosphorylation of styrene with red phosphorus
effectively proceeds in the system KOH DMSO under
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REACTIONS OF ELEMENTAL PHOSPHORUS AND PHOSPHINE... : XIX.
417
Phopshorylation of arylmethyl chlorides and styrene with red phosphorus under the conditions of phase transfer catalysis
and microwave irradiationa
Yield, b
%
Conversion, %
Irradiation
duration,
min
Run
no.
W,
Wt
Electrophile
electro-
phile
phos-
phorus
R3P=O R2P(O)Hc RP(O)H(OH) RP(O)(OH)2 R2P(O)OH
1
2
3
4
5
6
7
8
9
PhCH2Cl
PhCH2Cl
PhCH2Cl
PhCH2Cl
PhCH2Cl
1-C10H7CH2Cl
1-C10H7CH2Cl
1-C10H7CH2Cl 600
PhCH=CH2
90
10
78
61
72
62
62
69
68
66
83
69
34
8
12
5
2
traces
8
85
100
77
92
94
100
89
74
88
90
65
100
64
76
67
100
64
61
100
100
100
d
d
e
e
e
360
360
3
5
5
13
5
6
17
6
9
5
2
5
traces
600
2.5
17
18
8
16
6
traces
d
d
e
7
e
e
e
e
e
e
90
10
2.5
4
e
12
600
traces
traces
3
2
2
2
10 PhCH=CH2
11 PhCH=CH2
360
6
2
3
d
d
91
a
All experiments were carried out in an argon atmosphere. In nos. 1 5 100 mmol of red phosphorus, 20 mmol of benzyl chloride,
625 mmol of KOH, 15 ml of water, 2.2 mmol of TEBAC and 40 ml of dioxane was used; in nos. 6 8 32.6 mmol of red phosphorus,
6.5 mmol of 1-chloromethylnaphthalene, 208 mmol of KOH, 5 ml of water, 0.75 mmol of TEBAC and 20 ml of dioxane was used;
in nos. 9 11 100 mmol of red phosphorus, 104 mmol of styrene, 178 mmol of KOH, 1.5 ml of water, 0.1 g of hydroquinone and
b
c
40 ml of DMSO was used. Yield of products is given with respect to the reacted electrophile. Yield of the secondary phosphine
31
d
oxide in nos. 1, 3, 4, 7, 9 11 was calculated taking into account the data of P NMR spectra. nos. 2, 6, and 11 were performed
e
upon heating of the reagents to 90 95 C during 3 h without microwave irradiation.
Not formed.
Cl
H
O
KOH/H2O
+
+ Pn
P
P
MW
O
VI
VII
(2)
HCl/H2O
+
H
H
P
P
O
KO
O
HO
VIII
of styrene substantially decreases: the yield of com-
pounds IX XII is 34, 3, 3, and 2%, respectively
(see the table, no. 11).
styrene with red phosphorus a novel method of com-
bined activation of activation of electrophile phos-
phorylation that includes simultaneous action of
superbases and microwave irradiation is elaborated.
As a result, the corresponding tertiary phosphine
Therefore, on the example of direct reactions of
benzyl chloride, 1-chloromethylnaphthalene and
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 3 2007

418
MALYSHEVA et al.
O
KOH/DMSO (H2O)
MW
+ Pn
P
IX
O
H
O
O
H
(3)
+
+
+
P
P
P
OK
OK
X
HCl/H2O
O
O
H
+
P
P
OH
OH
XI
XII
oxides are prepared in high yield. These organophos-
phorus compounds are the compounds of choice for,
e.g., the design of nanomaterials [20, 21]. In addition,
tribenzylphosphine oxide was successfully used in the
Horner Wittig reaction of synthesis of substituted
alkenes of various structure [11, 22 25]. It was also
shown to be an effective antipyrene for polyvinyl
chloride plastisols [26, 27]. Catalytic systems based
on nickel complexes with tris(2-phenylethyl)phos-
phine oxide exert high activity and selectivity in the
reactions of dimerization and oligo-merization of
olefins (in particular, ethylene and styrene) [12, 28].
Tris(1-naphthylmethyl)phosphine oxide was proposed
as a luminophore for preparation of special liquid and
solid scintillators [1], which can be used for solving
of such a fundamental problem as detection of
neutrino [29].
LG Electronics Ins. MS-192 A equipped with con-
denser. GC analysis was performed on a PAKhV-07
chromatograph, column 1200 10 mm, 15% of
Carbowax-6000 on Chromaton N-AW-DMGS (0.25
0.36mm), gas-carrier is helium. All experiments were
run in an argon atmosphere. Parameters of NMR
spectra for compounds I XII are identical to the
earlier obtained spectral characteristics [1, 19, 30 33].
The yield of compounds I XII was calculated with
respect to the reacted electrophile.
Tribenzylphosphine oxide (I) (no. 1). Mixture of
3.10 g of red phosphorus, 2.53 g of benzyl chloride,
0.5g of benzyl triethylammonium chloride, 35 g of
KOH, 15ml of water and 40 ml of dioxane was ir-
radiated in the microwave oven (90 Wt) for 10 min.
The reaction mixture was cooled, diluted with water,
the unreacted phosphorus was filtered off, washed
with water to neutral reaction and dried in air to
recover 1.1 g of phosphorus (conversion 65%). The
filtrate was extracted with chloroform, combined
chloroform extract washed with water, dried over
K2CO3, the solvent and unreacted benzyl chloride
were removed to recover 0.38 g of benzyl chloride
(conversion 85%). The amount of benzyl chloride was
determined by GC with octane as a standard. The
EXPERIMENTAL
IR spectra were recorded on a Specord IR-75 in-
1
strument. H, 13C, and 31P NMR spectra were regis-
tered on a Bruker DPX 400 spectrometer (400, 100,
and 161.98 MHz, respectively), internal standard
HMDS, solvent CDCl3. Microwave irradiation was
performed in a modified domestic microwave oven
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 3 2007

REACTIONS OF ELEMENTAL PHOSPHORUS AND PHOSPHINE... : XIX.
419
residue was dried under vacuum to afford 1.6 g of
white powder. Its 31P NMR spectrum contains the
signals at 40.1 ppm (phosphine oxide I) and 35.5
as a standard. The residue was dried under vacuum to
afford 10 g of white powder. Its31P NMR spectrum
contains the signals at 45.19 ppm (phosphine oxide
1
1
ppm, JPH 468 Hz (phosphine oxide II) [19] in the
IX) [30] and 30.56 ppm, JPH 455 Hz (phosphine
ratio of 9:1. The reaction product was washed with
benzene (3 2 ml), dried in vacuum, obtained 1.42 g
(78%) of phosphine oxide I, mp 214 215 C (mp 216
217 C [19]). Found, %: C 78.64; H 6.70; P9.56.
C21H21OP. Calculated, %: C 78.73; H 6.61; P9.67.
oxide X) [31] in the ratio of 93:7. This mixture was
dissolved in 40 ml of ethanol, added 0.23 ml of H2O2
(35.5%,
1.135) and stirred for 1h at 50 C. The
solvent was removed, the residue dissolved in 70 ml
of benzene, added 0.5 g of KOH and stirred at room
temperature for 0.5 h. The suspension obtained was
filtered through NaHCO3, benzene distilled off, the
residue dried in vacuum to obtain 9.3 g of phosphine
oxide IX, mp 159 C (mp 157 C [30]). Found, %: C
78.4; H 7.69; P 8.20. C24H27OP. Calculated, %:
C 79.56; H 7.46; P 8.56.
The aqueous layer was acidified with HCl to pH
4 5, extracted with chloroform, chloroform extract
dried over CaCl2 and removed the solvent to obtain
0.27 g of the product containing, according to 31P
NMR, phosphine oxide II and acids III V in the
ratio of 8:24:7:61.
The aqueous layer was acidified with HCl to pH
5, extracted with chloroform, chloroform extract dried
over CaCl2 and removed the solvent to obtain 0.45 g
of the product containing, according to 31P NMR,
phosphine oxide X and acids XI and XII [32, 33] in
the ratio of 12:38:50.
Tris(1-naphthylmethyl)phosphine oxide (VI)
(run 7). Mixture of 1.01 g of red phosphorus, 1.15 g
of 1-chloromethylnaphthalene, 0.17 g of benzyl tri-
ethylammonium chloride , 11.67 g of KOH, 5 ml of
water and 20 ml of dioxane was irradiated in the
microwave oven (90 Wt) for 10 min. The reaction
mixture was cooled, diluted with water, the unreacted
phosphorus was filtered off, washed with water to
neutral reaction and dried in the air to recover 0.36 g
of phosphorus (conversion 64%). The filtrate was
extracted with chloroform, combined chloroform ex-
tract washed with water, dried over K2CO3, the sol-
vent removed, the residue evacuated to obtain 0.88 g
of beige powder. Its 31P NMR spectrum contains the
signals at 42.51 ppm (phosphine oxide VI) and
ACKNOWLEDGMENTS
This work was performed with financial support
from Russian Foundation for Basic Research (Grant
no. 05-03-32859) and Siberian Branch of Russian
Academy of Sciences (Integration Project no. 32).
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