Synthesis and properties of tert-butylphenylmethylene(chloro)phosphorane

Article abstract of DOI:10.1134/S1070363215070117

The synthesis and properties of tert-butylphenylmethylene(chloro)phosphorane were described. The prepared chlorophosphorane reacted with alcohols and phenol with the formation of the corresponding phosphonium salts. Its reaction with carbonyl compounds le

Full text of DOI:10.1134/S1070363215070117

ISSN 1070-3632, Russian Journal of General Chemistry, 2015, Vol. 85, No. 7, pp. 1639–1643. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © O.O. Kolodyazhna, E.V. Grishkun, S.Yu. Sheiko, A.O. Kolodyazhna, O.I. Kolodyazhnyi, 2015, published in Zhurnal Obshchei
Khimii, 2015, Vol. 85, No. 7, pp. 1115–1119.
Synthesis and Properties
of tert-Butylphenylmethylene(chloro)phosphorane
O. O. Kolodyazhna, E. V. Grishkun, S. Yu. Sheiko,
A. O. Kolodyazhna, and O. I. Kolodyazhnyi
Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine,
ul. Murmanskaya 1, Kiev, 02094 Ukraine
e-mail: olegkol321@rambler.ru
Received February 20, 2015
Abstract—The synthesis and properties of tert-butylphenylmethylene(chloro)phosphorane were described. The
prepared chlorophosphorane reacted with alcohols and phenol with the formation of the corresponding
phosphonium salts. Its reaction with carbonyl compounds led to the formation of 2-chloro-1,2λ5-oxaphos-
phetanes, which rearranged providing 2-chloroalkylphosphine oxides or alkenylphosphine oxides.
Keywords: 1,2λ5-oxaphosphetanes, alkylidenphosphoranes, phosphine oxides, alkenylphosphine oxides
DOI: 10.1134/S1070363215070117
The reactions of phosphorus ylides with carbonyl
compounds are of great practical importance [1–6]. An
interesting type of the phosphorus ylides are
practically accessible and highly reactive P-halogen
alkylidenphosphoranes [5–8]. In the course of our
investigations on the chemistry of P-halogen ylides [7–
10], we synthesized unsymmetrically substituted tert-
butylphenylmethylene(chloro)phosphorane II by the
reaction of tert-butylphenyl(methyl)phosphine I with
tetrahalomethane in diethyl ether at –70°C. Ylide II
proved to be comparatively stable and can be isolated
by vacuum distillation.
Ylide II can easily add alcohols and phenols to the P=C
bond with the formation of the corresponding phos-
phonium salts III and V. Ylide II is also interesting as
an active chiral reagent for asymmetric synthesis.
Thus, the reaction of ylide II with chiral phenol
BINOL and L-menthol proceeded stereoselectively
with the formation of scalemic phosphonium salts IV
and VII (Scheme 1).
Methoxyphosphonium salt VII, whose formation
we succeeded to register by the means of 31P NMR
spectroscopy (δP = 90 ppm), at room temperature
converted to phosphine oxide (S)-VI. The comparison
of the angle of optical rotation of the phosphine oxide
prepared by us with the value described earlier [12]
allowed the establishment of its absolute configuration
as well as absolute configuration of the alkoxyphos-
phonium salt.
t-Bu
t-Bu
Cl
CCl4
P
P
Ph
Me −CHCl3
Ph
CH2
I
II
tert-Butylphenylmethylene(chloro)phosphorane II
also reacted with carbonyl compounds. The reaction
with benzaldehyde proceeded at cooling providing
stable at low temperature chlorooxaphosphetane VIII
which at temperature about 0°C rearranged into 2-
chlorooxaphosphine oxide IX (Scheme 2).
The structure of tert-butylphenylmethylene(chloro)-
phosphorane II was confirmed by the data of NMR
spectroscopy. Thus, chemical shift δP 93.5 ppm
distinctively indicated phosphonium nature of the
phosphorus atom involved into the P=С→Р+–С– group.
In the 13C NMR spectrum the doublet signal at 23 ppm
with the coupling constant of spin-spin interaction of
95 Hz was observed that corresponded to the carbanion
nature of the carbon atom.
As we showed earlier [7, 8], 2-chlorooxaphosphe-
tanes might be easily ionized at Р–Cl bond with the
formation of the corresponding cyclic oxyphos-
1639

1640
KOLODYAZHNA et al.
Scheme 1.
Bu-t
t-Bu
OMe
CH3
t-Bu
O
Cl−
P+ Ph
Me
P+
P
O2NC6H4O
III
Ph
Ph
CH3
MeOH
4-NO2C6H4OH
(S/R)-VI
V
t-Bu
Cl
P
OH
Ph
OH
CH2
II
L-Menthol
Bu-t
Ph
P
+
O
Me
Cl−
OMnt
CH3
t-Bu
Ph
t-Bu
O
P
Cl−
OH
P+
Ph
CH3
(SP)-IV
(SP)-VII
(S)-VI
Scheme 2.
H
Ph
H
Ph
Cl
O
P
O
O
t-Bu
Ph
H
t-Bu
Cl
t-Bu
Ph
PhCHO
P+
Cl−
P
P
t-Bu
Ph
CH2
Ph
Cl
Ph
IX
VIII
II
Scheme 3.
OH
O
H2O
t-Bu
Ph
CF3
Ph
CF3
Ph
CF3
Ph
P
O
O
P
t-Bu
Cl
t-Bu
Ph
Ph(CF3)C=O
XI
P
P+
t-Bu
Ph
CH2
Ph Cl−
O
P
CF3
Cl
Δ
t-Bu
Ph
X
II
−HCl
Ph
XII
phonium salts, which underwent 2-chlorooxaphos-
phetane→2-chlorooxyphosphine oxide rearrangement
as a result of the attack of chloride ion on the β-carbon
atom.
with the formation of 2-hydroxyalkylphosphine oxide
XI; the thermolysis of X provided the corresponding
alkenylphosphine oxide XII (Scheme 3).
In the mass spectrum of 2-chlorooxaphosphetane X
the peak of molecular ion was observed that indicated
the covalent character of the P–Cl bond. It was found
that the chemical shift of phosphorus in X depended on
the polarity of the solvent. Thus, in nonpolar solvents
The reaction of P-halogenylide II with trifluoro-
acetophenone led to the formation of 2-chlorooxa-
phosphetane X stable at room temperature. The latter
can be easily hydrolyzed under air humidity condition
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SYNTHESIS AND PROPERTIES OF tert-BUTYLPHENYLMETHYLENE(CHLORO)PHOSPHORANE
1641
(diethyl ether, pentane) the signals of δP were in the
strong field of the 31P NMR spectrum (from –3 to
10 ppm) that corresponded to the pentacoordinated
state of the phosphorus atom [5]. In polar solvents and
especially in the presence of Lewis acids like AlCl3 the
values of δP were shifted downfield. For example, for
compound IV the chemical shift of phosphorus, δP was
as follows (ppm): 9 (pentane), 22 (СН2С12), 30
(СНС13), 35 (СН3СN), 45 (СНС13 + А1С13, traces).
With the increase in amount of aluminum chloride up
to equimolar level the value of δP 100 ppm was
registered for 2-chlorooxaphosphetane VII that was in
accordance with the values of chemical shifts for the
known alkoxyphosphonium salts [5, 6] and apparently
indicated complete ionization of chlorophosphorane
with the formation of phosphonium salt XVI. The
dependence of the chemical shift value of phosphorus
in 2-chlorooxaphosphetanes on the solvent polarity and
on the presence of Lewis acid is in accordance with the
published data showing that chlorophosphoranes are
able to be ionized with the formation of phosphonium
structures. Herewith in the 31P NMR spectrum the
resultant signal is registered due to fast exchange in the
phosphorus coordination P(V) ⇄ P(IV). The value of
δP is shifted downfield proportionally to the increase in
the phosphonium structure content, which in its turn
depends on the solvent polarity [10].
The structure of 2-halogen-1,2λ5-oxaphosphetane X
was confirmed by 1H NMR spectroscopy. A significant
downfield shift of δ value of oxaphosphetane ring
protons (4.5–6.35 ppm) is worth a special attention. In
the 1H NMR spectra of the compounds possessing asym-
metric carbon atom C4 the magnetic nonequivalence of
protons СНaНb in the four-membered ring became
apparent because the geminal spin-spin interaction
arose between them. Each of the signals СНa and СНb
was the double doublet with the coupling constant with
phosphorus nucleus 2JPH = 20–22 Hz and a constant of
geminal interaction 2JHH = 16–17 Hz.
and 126.16 (31P) MHz with TMS as a reference. Mass
spectra were registered on an Agilent 1100 LC/MSD
spectrometer. The reagents, silica gel, and plates
Polіgram SIL G/UV254 used in the work were
purchased from commercial suppliers Fluka and Merck.
The starting methyl(tert-butyl)phenylphosphine I was
synthesized by the known method [14].
tert-Butylphenylmethylene(chloro)phosphorane
(II). Carbon tetrachloride (4 mL) was added dropwise
under inert atmosphere to a cooled to –78°C solution
of methyl(tert-butyl)phenylphosphine I (3.6 g, 0.02 mol)
in 5 mL of anhydrous diethyl ether. Then temperature
was increased to ambient, and the mixture was stirred
for 20 min. The precipitate and solvent were removed,
and the residue was distilled in vacuum. Yield 3 g
(70%), bp 45–50°C (0.008 mmHg). 1Н NMR spectrum
(CDCl3), δ, ppm: 1.58 d (9H, CH3, 3JPH 15.0 Hz), 2.48
2
d (2H, PCH2, JPH 20.0 Hz), 7.47 m and 7.49 m (5H,
C6H5). 13С NMR spectrum (CDCl3), δС, ppm: 23.20 d
2
3
(P=CH2, JРС 95.0 Hz), 27.6 d (CH3, JРС 15.0 Hz),
1
41.90 d (PC, JPC 45.0 Hz), 124.01, 124.89, 126.94,
131.8, 132.0. 31P NMR spectrum (CDCl3): δР 93.50 ppm.
Found, %: C 62.14; H 7.79; P 14.03. C11H16ClP. Cal-
culated, %: C 61.54; H 7.51; P 14.43.
tert-Butyl(methyl)(4-nitrophenoxy)(phenyl)phos-
phonium chloride (III). A solution of 4-nitrophenol
(0.02 mol) in minimal amount of THF was added at
cooling (–70°C) to a solution of chloro(tert-butyl)-
phenyl(methylene)phosphorane II (2.1 g, 0.01 mol) in
10 mL of diethyl ether. The precipitate formed was
filtered off and washed with a little of diethyl ether.
1
Yield 0.27 g (75%), decomposes upon heating. Н
NMR spectrum (CDCl3), δ, ppm: 1.71 d (9H, CH3,
3JPH 18.0 Hz), 3.10 d (3H, CH3, 2JPH 10.0 Hz), 8.50 d.d
(4H, C6H4), 7.75 m and 8.50 m (С6H5). 31P NMR
spectrum (CDCl3): δР 93.50 ppm. Found, %: C 58.12;
H 6.02; P 8.50. C17H21ClNO3P. Calculated, %: C
57.72; H, 5.98; P 8.76.
tert-Butyl[2'-hydroxy-(1,1'-binaphth-2-yl)oxy]-
(methyl)(phenyl)phosphonium chloride (S)-IV. A
solution of (R)-BINOL (3.1 g, 0.11 mol) in THF was
added at cooling (–78°C) to a solution of tert-butyl-
phenylmethylene(chloro)phosphorane II (2.1 g, 0.01 mol)
in anhydrous toluene. The mixture was stirred at this
temperature for 10 min. The precipitate formed was
filtered off and washed with anhydrous ether (2 ×
In summary, chloro(tert-butyl)phenyl(methylene)
phosphorane II was found to be highly reactive com-
pound that participated in the reaction of asymmetric
synthesis, [2+2]-cycloaddition with carbonyl compounds
with the formation of 2-chloro-1,2λ5-oxaphosphetanes,
which then were converted to β-substituted tertiary
phosphine oxides or alkenylphosphine oxides.
1
20 mL). Yield 0.46 g (90%). Н NMR spectrum
EXPERIMENTAL
(CDCl3), δ, ppm: 1.84 d (9H, CH3, 3JPH 20.0 Hz), 3.18
2
NMR spectra were recorded on a Varіan VXR-300
d (3H, JPH 15.0 Hz), 5.50 s (OH), 7.00–7.50 m (5H,
instrument operating at 300 (1H), 60 (13C), 225.8 (19F),
C6H5), 8.80 m (12H, C10H12). 13C NMR spectrum
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 7 2015

1642
KOLODYAZHNA et al.
(CDCl3), δС, ppm: 9.1 d (1JPC 55.0 Hz), 24.5 d (JPC
15.0 Hz), 35.2 d (JPC 42.0 Hz), 116.0, 122.5, 127.0,
128.3, 130.4, 131.4, 132.5, 134.6, 150.5, 154. 31P
NMR spectrum (CDCl3): δР 93.7, 94.6 ppm (3 : 1).
Found Р, %: 6.09. C31H30ClO2P. Calculated Р, %: 6.18.
ketone (0.02 mol) was added at cooling (–70°C) to a
solution of tert-butylphenylmethylene(chloro)-
phosphorane II (2.1 g, 0.01 mol) in 10 mL of diethyl
ether. The reaction mixture was allowed to warm up to
room temperature. The precipitate was filtered off, the
filtrate was evaporated. The residue (yield 95% by
NMR data) was recrystallized from hexane at –70°C.
tert-Butylmethylphenylphosphine oxide (S/R)-
VI. Methanol (0.4 mL, 0.01 mol) was added dropwise
to a solution of tert-butylphenylmethylene(chloro)-
phosphorane II (1.05 g, 0.005 mol) in 5 mL of diethyl
ether at –70°C. Then the reaction mixture was stirred
at room temperature for 30 min and kept for the
following 30 min without stirring. After removing the
solvent the residue was distilled in a vacuum and
additionally purified by re-precipitation with methanol
from methylene chloride solution. Yield 0.65 g (65%),
bp 90 °С (0.05 mmHg), mp 97°C (mp 98–99°C [12–
1
Yield 2 g (50%). Н NMR spectrum (CDCl3), δ, ppm:
3
1.76 d (9H, CH3, JPH 20.0 Hz), 5.16 m and 5.23 m
(2H, PCH2), 7.20–7.60 m (5H, C6H5). 13C NMR
spectrum (CDCl3), δС, ppm: 25.7 d (PC, 2JPC 15.0 Hz),
1
40.8, 52.5 d (PC, JPC 61.0 Hz), 91 dq (2JCP 10.0 Hz,
2JCF 25.0 Hz), 127.0 q (CF3, JCF 270.0 Hz), 125.4,
129.2, 130.4, 131.8, 140.5. 31Р NMR spectrum
(CDCl3): δP 2.99, 4.93 ppm (4 : 1). 19F NMR spectrum
(CDCl3), δF, ppm: 78.4, 78.3. Mass spectrum (70 eV):
m/e 388 [M]+. Found, %: C 58.85; H 5.49; P 7.91.
C19H21ClF3OP. Calculated , %: C 58.70; H 5.44; P
7.97.
1
14]). Н NMR spectrum (CDCl3), δ, ppm: 1.07 d (9H,
3
2
CH3C, JPH 14.9 Hz), 1.66 d (3H, CH3, JPH 12.2 Hz),
7.47–7.37 m (3H, ArH), 7.69–7.62 m (2H, ArH). 31Р
NMR spectrum (CDCl3): δP 47.75 ppm.
tert-Butyl(phenyl)(3,3,3-trifluoro-2-hydroxy-2-
phenylpropyl)phosphine oxide (XI). An open flask
with the solution of 2-tert-butyl-2-chloro-2,4-diphenyl-
tert-Butylmethylphenylphosphine oxide (S)-(–)-
VI was prepared similarly from tert-butylphenyl-
methylene(chloro)phosphorane II (2.1 g, 0.01 mol) and
L-menthol (1.7 g, 0.11 mol). Yield 1.5 g (75%), bp 90°С
(0.1 mmHg), mp 97°C (mp 98–99°C [12–14]), [λ]D20
4-trifluoromethyl-1,2λ5-oxaphosphetane
X
(1.8 g,
0.0048 mol) in 10 mL of hexane was placed into the
desiccator on the bottom of which water was poured to
form a thin layer. The formed colorless product of the
reaction insoluble in hexane was filtered off and
additionally purified by column chromatography
eluting with a mixture ethyl acetate–chloroform, 1 : 1.
Yield 1.2 g (65%), colorless crystals, mp 149–152 °С.
1Н NMR spectrum (CDCl3), δ, ppm: 1.22 d (9H, CH3,
1
–10 (с = 2, МeOH). Н NMR spectrum (CDCl3), δ,
3
ppm: 1.07 d (9H, CH3C, JPH 14.9 Hz), 1.66 d (3H,
CH3, 2JPH 12.2 Hz), 7.47–7.37 m (3H, ArH), 7.69–7.62 m
(2H, ArH). 31Р NMR spectrum (CDCl3): δP 47.75 ppm.
tert-Butyl(2-chloro-2-phenylethyl)(phenyl)phos-
phine oxide (IX). Benzaldehyde (0.02 mol) was added
at cooling (–70°C) to a solution of tert-butylphenyl-
methylene(chloro)phosphorane II (2.1 g, 0.01 mol) in
10 mL of diethyl ether. After removing the precipitate
and the solvent, the residue was recrystallized from a
2
3JPH 15.0 Hz), 2.60 t (1H, CH2, JPH 15.0 Hz), 2.80 t
2
(1H, CH2, JРН 15.0 Hz), 6.8 m (1Н, ОН), 7.4–7.6 m
(10Н, C6H5). 13C NMR spectrum (CDCl3), δС, ppm:
23.4, 27.1 d (1JРС 62.0 Hz), 33.5 d (J 65.0 Hz), 82.0,
125.0 q (1JСF 275.0 Hz), 128.0, 129.0, 130.0, 132.0,
133.0, 144.0. 31P NMR spectrum (CDCl3): δР 52.5
ppm. 19F NMR spectrum (CDCl3): δF 82.16 ppm.
Found, %: C 61.73; H 5.99; P 8.11. C19H22F3O2P.
Calculated, %: C 61.62; H 5.99; F 15.39; P 8.36.
1
mixture hexane–Et2O at –70°C. Yield 75%. Н NMR
3
spectrum (CDCl3), δ, ppm: 1.10 d (9H, CH3, JPH
2
3
15.0 Hz), 2.71 d.d (1H, PCH, JHP = JHH = 10.0 Hz),
2.95 d.d (1H, PCH, 2JHP = 3JHH = 10.0 Hz), 5.42 d (1H,
3
CHPh, JHH 10.0 Hz), 7.3–7.6 m (5H,C6H5). 13C NMR
Z-tert-Butyl(phenyl)(3,3,3-trifluoro-2-phenylprop-
1-en-1-yl)phosphine oxide (XII). Oxaphosphetane X
was heated at 149–150°C to the end of hydrogene
chloride emission. Then the reaction mixture was
cooled and the product was isolated by column
chromatography on silica gel eluting with hexane–
spectrum (CDCl3), δC, ppm: 23.7 (PCCH3), 32.8 d (PC,
1
1JPC 66.0 Hz), 34.9 d (PCH2, JPC 57.0 Hz), 57.2,
127.5, 127.8, 131.2, 131.5, 130.9, 131.5, 132.3 d
2
(PCC, JCP 25.0 Hz), 140.1. 31Р NMR spectrum
(CDCl3): δP 57.90, 58.33 ppm (10:1). Mass spectrum
(70 eV): m/e 320 [M]+. Found, %: C 67.27; H 6.89; P
9.54. C18H22ClOP. Calculated, %: C 67.39; H 6.91; P 9.66.
1
ethyl acetate mixture (10 : 1). Yield 35%. Н NMR
3
spectrum (CDCl3), δ, ppm: 1.50 d (9H, CH3, JHH
15.0 Hz), 6.90 d.d (1H, CH=, 2JPH 25.0 Hz, 4JHF 1.0 Hz),
2-tert-Butyl-2-chloro-2,4-diphenyl-4-trifluoro-
methyl-1,2λ5-oxaphosphetane (X). Trifluoromethyl phenyl
7.30–7.60 m (10H, C6H5). 31P NMR spectrum
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SYNTHESIS AND PROPERTIES OF tert-BUTYLPHENYLMETHYLENE(CHLORO)PHOSPHORANE
1643
(CDCl3): δР 32.0 ppm. 19F NMR spectrum (CDCl3): δF
–68.1 ppm. Mass spectrum (70 eV): m/e 352 [M]+.
Found, %: C 64.66; H 5.62; P 8.91. C19H20F3OP.
Calculated, %: C 64.77; H 5.72; P 8.79.
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