66
CHEREDILIN et al.
iodide (3.04 g, 6.41 mmol) was dissolved in 50 mL of was evaporated, the reaction mixture was quenched
tetrahydrofuran in an argon flow, and 4 mL of a 1.6M with a saturated aqueous solution of ammonium chlo-
solution of n-BuLi in hexane was added dropwise to ride (30 mL), 50 mL of dichloromethane was added,
the obtained solution cooled down to −5°C. After the the organic layer was separated (the aqueous phase
was extracted with CH2Cl2), the combined organic
phase was dried over sodium sulfate, and the solvent
was evaporated. The pale yellow solid was dissolved in
CH2Cl2, 5 mL of hexane was added, and a white finely
dispersed precipitate was formed. The solution was fil-
tered from the precipitate through a Schlenk filter tube
in an argon flow, the solvent was evaporated, and a
pale yellow crystalline substance was obtained after
drying under high vacuum.
addition of all the solution of n-BuLi, the resulting
mixture was stirred for 1 h, and then a solution of 0.68
mL (5.83 mmol) of 2-bromobenzaldehyde in 10 mL of
tetrahydrofuran was added dropwise. The temperature
of the reaction mixture was maintained at −2 to +2°C.
The solution turned orange, and a white precipitate
was formed. The mixture was warmed up to room tem-
perature, and stirred for 3 h; then, 30 mL of a saturated
solution of NaCl 30 mL of ethyl acetate were succes-
sively added. The phases were separated, and the bot-
tom aqueous layer was twice extracted with 30 mL of
ethyl acetate. The combined organic phases were dried
over anhydrous sodium sulfate and evaporated. The
residue after evaporation was purified by column
chromatography (silica gel (Acros), 60–200 μm, hex-
The yield of [(2-diphenylphosphino)phenyl][2-
(vinyl)phenyl]phenylphosphine (7) was 92%. 31P{1H}
NMR (161.98 MHz, CDCl3): δ (ppm) −13.7 (d, 3JPP
=
=
3
160 Hz, P(C6H4CH=CH2)Ph), −21.2 (d, JPP
160 Hz, PPh2). 1H NMR spectrum (400 MHz,
CDCl3): δ (ppm) 6.76–7.62 (m, 24H, CH=CH2, Ar–
H), 5.54 (dt, 1H, JHH = 17 Hz, JHH = 1 Hz,
CH=CHAHB), 5.08 (dd, 1H, JHH = 12 Hz, JHH
1 Hz, CH=CHAHB).
1
ane as the eluent). Yield 1.4 g (95%). H NMR (400
MHz, CDCl3) (mixture of E- and Z-isomers at a
molar ratio of 1 : 2.5): δ (ppm) 7.61 (d, J = 7 Hz, 2.5H,
Ar–H), 7.56 (d, J = 7 Hz, 1H, Ar–H), 7.36–7.23 (a
set of m, 7H, Ar–H), 7.18–7.04 (a set of m, 3.5H, Ar–
H), 6.75 (br. dt, J = 16 Hz, 1H, CH=CH), 6.49 (br. dt,
J = 12 Hz, 2.5H, CH=CH), 6.21 (dt, J = 7 Hz, 1H,
CH=CH), 5.81 (dt, J = 7 Hz, 2.5H, CH=CH), 2.29
(dq, J = 7 Hz, J = 1.5 Hz, 2H, =CH–CH2), 2.21 (dq,
J = 7 Hz, J = 1.5 Hz, 5H, =CH–CH2), 1.59–1.24 (a
set of m, 21H, CH2), 0.95 (t, J = 7 Hz, 3H, CH3), 0.91
(t, J = 7 Hz, 7.5H, CH3).
=
1-Bromo-2-(2-methyl-1-propenyl)benzene was used
for the synthesis of [(2-diphenylphosphino)phenyl][2-(2-
methyl-1-propenyl)phenyl]phenylphosphine instead of
2-bromostyrene. The yield of [(2-diphenylphos-
phino)phenyl][2-(2-methyl-1-propenyl)phenyl]phenyl-
phosphine (8) was 91%. 31P{1H} NMR (161.98 MHz,
CDCl3): δ (ppm) −14.4 (d, 3JPP = 159 Hz, P(C6H4CH=
C(CH3)2)Ph), −19.7 (d, 3JPP = 159 Hz, PPh2). 1H NMR
spectrum (400 MHz, CDCl3): δ (ppm) 7.14–7.03 (m,
23H, Ar–H), 6.68 (m, 1H, CH=C(CH3)2), 1.55 (s, 3H,
CH=C(CH3)2), 1.38 (s, 3H, CH=C(CH3)2).
General procedure for the synthesis of diphosphine
ligands 7–11 exemplified by the synthesis of [(2-diphenyl-
phosphino)phenyl][2-(vinyl)phenyl]phenylphosphine (7).
Magnesium in amount of 0.28 g (11.54 mmol) was placed
into a 100-mL Schlenk flask, calcined in a vacuum, and
purged with argon, and 50 mL of absolute tetrahydrofuran
and a catalytic amount of iodine were added. A solution of
1.92 g (10.49 mmol) of 2-bromostyrene in 20 mL of tetra-
hydrofuran was separately prepared, and several drops
of the prepared solution were added to the reaction
flask. The mixture was heated to reflux without stir-
ring, the solution gradually became colorless, and the
remaining solution of 2-bromostyrene was slowly
added to the refluxing mixture. The solution turned
brown-yellow. The solution was refluxed with stirring
for 4 h. The mixture was cooled to room temperature.
An additional amount of tetrahydrofuran was added to
dilute the resulting thick brown solution. The prepared
solution of the Grignard reagent was filtered in an
argon flow. The solution was cooled to −30°C, and a
solution of 2.97 g (7.34 mmol) of [(2-diphenylphos-
phino)phenyl]phenylphosphine chloride {P–PCl} in
20 mL of tetrahydrofuran was added to it dropwise.
The temperature rose to −15°C. The cooling was
removed, and the reaction mixture was allowed to
warm up to room temperature, after which the mixture
was stirred at this temperature for one day. The solvent
2-Bromostilbene was used for the synthesis of
[(2-diphenylphosphino)phenyl][2-(2-phenyl-1-ethe-
nyl)phenyl]phenylphosphine instead of 2-bromosty-
rene. The yield of [(2-diphenylphosphino)phenyl][2-
(2-phenyl-1-ethenyl)phenyl]phenylphosphine (9) was
96%. 31P{1H} NMR (161.98 MHz, CDCl3): δ (ppm) (a
mixture of isomers of 1 : 0.7) −13.8 (d, 3JPP = 160 Hz,
3
1P, P(C6H4CH=CH2)Ph), −14.9 (d, JPP = 157 Hz,
0.7P, P(C6H4CH=CH2)Ph); −20.4 (d, 3JPP = 160 Hz,
1P, PPh2), −21.3 (d, 3JPP = 157 Hz, 0.7P, PPh2).
1-Bromo-2-(hept-1-enyl)benzene was used for the syn-
thesis of [(2-diphenylphosphino)phenyl][2-(2-n-pentyl-1-
ethenyl)phenyl]phenylphosphine instead of 2-bromosty-
rene. The yield of [(2-diphenylphosphino)phenyl][2-(2-n-
pentyl-1-ethenyl)phenyl]phenylphosphine (10) was 82%.
31P{1H} NMR (161.98 MHz, CDCl3): δ (ppm) (a mixture
of isomers of 1 : 2.5 (cis- and trans-isomers)) −13.8 (d,
3JPP = 160 Hz, 2.5P, P(C5H11CH=CH2)Ph), −14.2 (d,
3JPP = 158.5 Hz, 1P, P(C5H11CH=CH2)Ph), −20.4 (d,
3JPP = 158.5 Hz, 1P, PPh2), −20.5 (d, 3JPP = 160 Hz, 2.5P,
PPh2).
PETROLEUM CHEMISTRY
Vol. 60
No. 1
2020
Afanas’ev, V. V.
