A facile synthesis of 1-H-2,2-difluorovinylphosphorus compounds from 2,2,2-trifluoroethyl trifluoromethanesulfonate and substitutions of their vinylic fluorines

Article abstract of DOI:10.1016/S0022-1139(99)00037-8

2,2-Difluorovinylphosphine as well as its oxide and borane-complex are synthesized in high yields via the P-trifluoroethylation of lithium diphenylphosphide with 2,2,2-trifluoroethyl trifluoromethanesulfonate, followed by dehydrofluorination with potassiu

Full text of DOI:10.1016/S0022-1139(99)00037-8

Journal of Fluorine Chemistry 97 (1999) 109±114
A facile synthesis of 1-H-2,2-di¯uorovinylphosphorus compounds
from 2,2,2-tri¯uoroethyl tri¯uoromethanesulfonate and
substitutions of their vinylic ¯uorines
Junji Ichikawa*, Hideharu Jyono, Satoshi Yonemaru, Tatsuo Okauchi, Toru Minami1
Department of Applied Chemistry, Kyushu Institute of Technology, Sensui-cho, Tobata, Kitakyushu 804-8550, Japan
Received 17 December 1998; received in revised form 25 January 1999; accepted 25 January 1999
Dedicated to Professor Emeritus Yoshiro Kobayashi with deep respect on the occasion of his 75th birthday
Abstract
2,2-Di¯uorovinylphosphine as well as its oxide and borane-complex are synthesized in high yields via the P-tri¯uoroethylation of lithium
diphenylphosphide with 2,2,2-tri¯uoroethyl tri¯uoromethanesulfonate, followed by dehydro¯uorination with potassium tert-butoxide. The
reactions of 2,2-di¯uorovinylphosphine oxide and borane-complex with hydride, S- and N-nucleophiles proceed via an addition±
elimination process to afford mono- or non¯uorovinylphosphorus compounds and carbamoylmethylphosphine oxides. # 1999 Elsevier
Science S.A. All rights reserved.
Keywords: Fluorovinylphosphorus compound; Tri¯uoroethylation; Tri¯ate; Dehydro¯uorination; Substitution; Vinylic ¯uorine
1. Introduction
sulfonate and substitution reactions of the resulting vinylic
¯uorines.
Vinylphosphorus compounds such as phosphonium salts,
phosphonates, and phosphine oxides have received signi®-
cant attention as versatile intermediates in the syntheses of
heterocyclic, carbocyclic, and chain-extended systems [1±
4]. In this sense, ¯uorine-containing vinylphosphorus spe-
cies are potential building blocks for the synthesis of
selectively ¯uorinated compounds. Fluorine substitution
provides the unique advantage of markedly affecting elec-
tron density distribution and related properties. Only a
limited number of methods have been available for the
preparation of ¯uorinated vinylphosphorus compounds
despite the utility of these species [2,5±8].
In our recent publication we have illustrated a new route
to 2,2-di¯uorovinyl- and 2-¯uorovinylphosphorus com-
pounds bearing a substituent at the 1-position of the vinyl
group [9]. To the best of our knowledge, there have been no
reports of synthetic methods for 2,2-di¯uorovinylpho-
sphorus compounds bearing no 1-substituent. We describe
here a route to these simple di¯uorovinylphosphorus com-
pounds starting from 2,2,2-tri¯uoroethyl tri¯uoromethane-
2. Syntheses of 1-nonsubstituted 2,2-
difluorovinylphosphorus compounds
Our synthetic plan for 2,2-di¯uorovinylphosphine (3) was
(i) the introduction of a 2,2,2-tri¯uoroethyl group on phos-
phorus, followed by (ii) dehydro¯uorination, which would
furnish the phosphorus atom with the di¯uorovinyl substi-
tuent, as shown in Scheme 1. Although tri¯uoroethylating
reagents (CF3CH2X) are generally poor electrophiles
because of the electronegativity of the CF3 group [10±
14], the reaction depicted in Scheme 1 proceeded in high
yield. Use of the potent tri¯ate (XˆOSO2CF3) leaving group
(O-tri¯uoroethylation [15,16], N-tri¯uoroethylation [17,18],
C-tri¯uoroethylation [19]) in conjunction with the strongly
nucleophilic diphenylphosphide ion effectively promoted
the rarely observed P-tri¯uoroethylation we desired. Dehy-
dro¯uorination of the resulting tri¯uoroethylphosphine with
base afforded the 2,2-di¯uorovinylphosphine.
Lithium diphenylphosphide, generated in situ from diphe-
nylphosphine and butyllithium, readily reacted with tri¯uor-
oethyl tri¯ate (1) in tetrahydrofurane (THF) even at 788C
to afford the desired diphenyl(tri¯uoroethyl)phosphine (2)
*Corresponding author. Tel.: +81-93-884-3314; fax: +81-93-884-3314;
e-mail: ichikawa@che.kyutech.ac.jp
1Co-corresponding author
0022-1139/99/$ ± see front matter # 1999 Elsevier Science S.A. All rights reserved.
PII: S 0 0 2 2 - 1 1 3 9 ( 9 9 ) 0 0 0 3 7 - 8

110
J. Ichikawa et al. / Journal of Fluorine Chemistry 97 (1999) 109±114
Scheme 1.
in 83% yield. Minimal tri¯uoroethylation occurred with
tri¯uoroethyl iodide (XˆI), con®rming the potent tri¯uor-
oethylating ability of 1 [15±19]. Next, conditions employing
several bases were examined to effect dehydro¯uorination
of 2. Lithium diisopropylamide (LDA) and butyllithium
caused the replacement of the CF3CH2 group at the phos-
phorus center. In order to prevent such nucleophilic attack,
less nucleophilic bases were examined. Among lithium
2,2,6,6-tetramethylpiperidide, tert-butyllithium, and potas-
sium tert-butoxide, only the last successfully achieved the
deprotonation in THF to give (2,2-di¯uorovinyl)diphenyl-
phosphine (3) in 75% yield.
Scheme 2.
Thus obtained, 3 was transformed to several phosphorus
derivatives. Treatment of 3 with hydrogen peroxide or
borane provided phosphine oxide (4) and phosphine-borane
(5) in 89% and 91% yields, respectively (Scheme 2).
3. Vinylic fluorine substitution of 1-H-2,2-
difluorovinylphosphorus compounds
Scheme 3.
4 and 5 have a highly electrophilic carbon±carbon double
bond doubly activated by either a P(O)Ph2 or P(BH3)Ph2
group and two ¯uorine atoms [20±23]. Reaction of these
activated ole®ns with nucleophiles effects the substitution of
the ¯uorines via an addition±elimination process, leading to
mono- and/or non¯uorovinylphosphorus compounds [9].
On treatment with lithium aluminum hydride, 4 was selec-
tively converted into the expected mono¯uorinated com-
pound (6) in 73% yield (Z/Eˆ95/5).2,3 Examination of
several hydride reagents revealed that LiAlH(OtBu)3
brought about better results for the reduction of both 4
and 5 to give 6 (92%, E/Zˆ96/4) and 7 (87%, E/Zˆ82/18),
respectively (Scheme 3).1,2 When benzenethiolate was
employed as a nucleophile, a similar substitution of the
¯uorines took place to yield the mono- or di-substituted
product 8 (83%, E/Zˆ90/10) or 9 (84%), depending on the
amount of the added thiolate. This result indicates that the
substitution of the two vinylic ¯uorines can be controlled in
a stepwise fashion.
Scheme 4.
with tert-butylamine, aqueous workup gave an 85% yield of
N-tert-butyl(diphenylphosphinoyl)acetamide (11), prob-
ably by addition of water to the ketenimine (Scheme 4).4
In the case of secondary amines, the same reaction followed
by treatment with aqueous sodium hydroxide afforded N,N-
disubstituted (carbamoylmethyl)phosphine oxides (12) in
high yields (Scheme 4). This sequence of reactions
effectively affords phosphinoylacetylation of primary and
secondary amines to provide the corresponding a-phosphi-
noylamides.
We also investigated the reaction of 4 with primary
amines to produce phosphinoylketenimines (10) [24]
through double dehydro¯uorination. While 4 readily reacted
4. Conclusions
2The E/Z ratio was determined by GLC analysis of the reaction mixture.
The configuration was assigned by 1H and 19F NMR measurement on the
basis of the vinylic 1H±1H, 1H±31P, 1H±19F, and 19F±31P coupling
The reactions described herein provide novel 1-H-2,2-
di¯uorovinylphosphorus compounds such as free phosphine
constants to bear the relationship of Jtrans>Jcis
.
3The reaction should be quenched under acidic conditions to prevent
E/Z isomerization.
4Ketenimine 10 was detected by 1H NMR measurement after nonaqu-
eous workup.

J. Ichikawa et al. / Journal of Fluorine Chemistry 97 (1999) 109±114
111
(3), phosphine oxide (4), and phosphine-borane (5). Further-
more, 2-¯uorovinylphosphorus compounds (6±8), 2-substi-
tuted vinylphosphine oxide (9), and (carbamoyl-
methyl)phosphine oxides (11, 12) are also readily obtained
from the reaction of 4 or 5 with appropriate nucleophiles.
The vinylic substitutions demonstrate that ¯uorine acts as a
powerful functional group for further synthetic elaborations
as well as an electronically unique substituent.
the mixture was stirred for 30 min at 788C, the reaction
was quenched with degassed water. Organic materials were
extracted with dichloromethane three times. The combined
extracts were washed with brine, and then dried over
Na2SO4. After removal of the solvent under reduced pres-
sure, the residue was puri®ed by column chromatography on
silica gel (chloroform) to give 3 as a colorless solid (346 mg,
75%). m.p. 32±348C. IR (KBr) 3060, 1695, 1440, 1300,
1
1150, 955, 740, 695 cm . 1H NMR (500 MHz, CDCl3) ꢀ:
4.84 (1H, ddd, JHFˆ28.0, 5.3 Hz, JHPˆ3.3 Hz), 7.32±7.42
(10H, m). 13C NMR (126 MHz, CDCl3) ꢀ: 74.8 (ddd, JCF or
JCPˆ21, 16, 10 Hz), 128.6 (d, JCPˆ6 Hz), 128.9, 132.4 (d,
JCPˆ20 Hz), 137.6 (d, JCPˆ7 Hz), 160.0 (ddd, JCFˆ302,
294 Hz, JCPˆ33 Hz). 19F NMR (470 MHz, CDCl3) 86.9
(1F, ddd, JFPˆ44 Hz, JFHˆ28 Hz, Jˆ12 Hz), 96.2 (1F,
ddd, Jˆ12 Hz, JFPˆ7 Hz, JFHˆ5 Hz) ppm. 31P NMR
(202 MHz, CDCl3) 33.3 (dd, JPFˆ43, 8 Hz) ppm. MS
5. Experimental details
General: IR spectra were recorded on a Shimadzu IR-408
spectrometer. NMR spectra were obtained on JEOL JNM-
FX-60, JNM-FX-100, JNM-EX-270, or JNM-A-500 spec-
trometers. Chemical shift values were given in ppm relative
1
to internal Me4Si (for H and 13C NMR : ꢀ-value), H3PO4
‡
(for 31P NMR), or C6F6 (for 19F NMR). Mass spectra were
taken with a JEOL JMS-DX-300 spectrometer. Elemental
analyses were performed with a YANAKO MT-3 CHN
Corder apparatus. THF was distilled from sodium benzo-
phenone ketyl prior to use.
(70 eV) m/z (rel. intensity) 248 (M ; 52), 164 (63), 122
‡
(100), 91 (53). HRMS calcd. for C14H12F3P 248.0566 (M );
found 248.0560.
5.3. (2,2-Difluorovinyl)diphenylphosphine oxide (4)
5.1. Diphenyl(2,2,2-trifluoroethyl)phosphine (2)
To a solution of (2,2-di¯uorovinyl)diphenylphosphine (3,
30 mg, 0.12 mmol) in THF (2 ml) was added 30% hydrogen
peroxide (0.2 ml) at 08C. After the mixture was stirred for
10 min at 08C, the reaction was quenched with water.
Organic materials were extracted with dichloromethane
three times. The combined extracts were washed with brine,
and then dried over Na2SO4. After removal of the solvent
under reduced pressure, the residue was puri®ed by thin
layer chromatography on silica gel (chloroform±ethyl ace-
tate 1:1) to give 4 as a colorless solid (31 mg, 97%). m.p.
108±1108C. IR (KBr) 2980, 1705, 1440, 1325, 1195, 1120,
To a solution of diphenylphosphine (80 mg, 0.43 mmol)
in THF (2 ml) was added butyllithium (0.31 ml, 1.53 M in
hexane, 0.47 mmol) at 788C over 10 min under an argon
atmosphere. After the reaction mixture was stirred for
30 min at 788C, 2,2,2-tri¯uoroethyl tri¯uoromethanesul-
fonate (1, 100 mg, 0.39 mmol) in THF (1 ml) was added to
the mixture. The reaction was quenched with degassed
water after stirring for 2 h. Organic materials were extracted
with dichloromethane three times. The combined extracts
were washed with brine, and then dried over Na2SO4. After
removal of the solvent under reduced pressure, the residue
was puri®ed by column chromatography on silica gel
(chloroform), and then Kugelrohr distillation gave 2 as a
colorless liquid (86 mg, 83%). IR (neat) 1295, 1260, 1230,
1
970, 795, 755, 720, 695 cm . 1H NMR (270 MHz, CDCl3)
ꢀ: 5.04 (1H, ddd, JHFˆ28.4, 5.3 Hz, JHPˆ5.3 Hz), 7.21±7.60
(6H, m), 7.60±7.88 (4H, m). 13C NMR (126 MHz, CDCl3)
ꢀ: 74.4 (ddd, JCPˆ106 Hz, JCFˆ18, 13 Hz), 128.8 (d,
JCPˆ13 Hz), 131.0 (d, JCPˆ10 Hz), 132.3 (d, JCPˆ3 Hz),
132.4 (dd, JCPˆ112 Hz, JCFˆ2 Hz), 160.4 (ddd, JCFˆ308,
303 Hz, JCPˆ5 Hz). 19F NMR (94 MHz, CDCl3) 98.9 (1F,
ddd, JFHˆ28 Hz, Jˆ8 Hz, JFPˆ7 Hz), 102.2 (1F, ddd,
JFPˆ22 Hz, Jˆ8 Hz, JFHˆ5 Hz) ppm. 31P NMR
(202 MHz, CDCl3) 19.3 (dd, JPFˆ22, 7 Hz) ppm. MS
1
1110, 1045, 735, 695 cm . 1H NMR (500 MHz, CDCl3) ꢀ:
2.89 (2H, q, JHFˆ11.6 Hz), 7.33±7.45 (10H, m). 13C NMR
(126 MHz, CDCl3) ꢀ: 35.1 (qd, JCFˆ28 Hz, JCPˆ23 Hz),
126.6 (qd, JCFˆ275 Hz, JCPˆ16 Hz), 128.8 (d, JCPˆ7 Hz),
129.4, 132.7 (d, JCPˆ21 Hz), 136.4 (d, JCPˆ11 Hz).
19F NMR (94 MHz, CDCl3) 103.0 (dt, JFPˆ15 Hz, JFHˆ12
Hz) ppm. 31P NMR (202 MHz, CDCl3) 26.9 (q, JPFˆ
‡
(70 eV) m/z (rel. intensity) 264 (M ; 84), 263 (100), 77
(66), 51 (37). Anal. calcd. for C14H11F2OP: C, 63.64; H,
4.20. Found C, 63.62; H, 4.36.
‡
15 Hz) ppm. MS (70 eV) m/z (rel. intensity) 268 (M ; 53),
201 (87), 183 (92), 77 (100). HRMS calcd. for C14H12F3P
‡
268.0628 (M ); found 268.0589.
5.4. (2,2-Difluorovinyl)diphenylphosphine-borane (5)
5.2. (2,2-Difluorovinyl)diphenylphosphine (3)
To a solution of (2,2-di¯uorovinyl)diphenylphosphine (3,
333 mg, 1.34 mmol) in THF (5 ml) was added borane±THF
(1.48 ml, 1.0 M in THF, 1.48 mmol) at 08C. After the
mixture was stirred for 15 min at 08C, the reaction was
quenched with phosphate buffer (pH 7). Organic materials
were extracted with dichloromethane three times. The
To a solution of potassium tert-butoxide (440 mg,
3.92 mmol) in THF (10 ml) was added dropwise diphe-
nyl(2,2,2-tri¯uoroethyl)phosphine (2, 500 mg, 1.87 mmol)
in THF (3 ml) at 788C under an argon atmosphere. After

112
J. Ichikawa et al. / Journal of Fluorine Chemistry 97 (1999) 109±114
combined extracts were washed with brine, and then dried
over Na2SO4. After removal of the solvent under reduced
pressure, the residue was puri®ed by thin layer chromato-
graphy on silica gel (hexane±ether 5:1) gave 5 as a colorless
solid (308 mg, 88%). m.p. 32±348C. IR (neat) 3070, 2420,
JCFˆ281 Hz, JCPˆ7 Hz). 19F NMR (470 MHz, CDCl3)
70.6 (ddd, JFHˆ83, 48 Hz, JFPˆ9 Hz) ppm. 31P NMR
(202 MHz, CDCl3) 19.8 (d, JPFˆ9 Hz) ppm. MS (70 eV)
‡
m/z 246 (M ), 245, 77 (base peak). HRMS calcd. for
‡
C14H12FOP 246.0609 (M ); found 246.0570. Anal. calcd.
for C14H12FOP: C, 68.29; H, 4.91. Found C, 68.22; H, 5.06.
1710, 1490, 1440, 1320, 1175, 1110, 1060, 980, 735,
1
695 cm
.
1H NMR (500 MHz, CDCl3) ꢀ: 0.78±1.50
(3H, m), 4.82 (1H, ddd, JHFˆ28.3, 5.1 Hz, JHPˆ2.7 Hz),
7.43±7.53 (6H, m), 7.64±7.70 (4H, m). 13C NMR
(126 MHz, CDCl3) ꢀ: 70.2 (ddd, JCPˆ61 Hz, JCFˆ17,
17 Hz), 128.7 (d, JCPˆ61 Hz), 129.0 (d, JCPˆ10 Hz),
131.6 (d, JCPˆ3 Hz), 132.2 (d, JCPˆ10 Hz), 159.8 (ddd,
JCFˆ305, 303 Hz, JCPˆ7 Hz). 19F NMR (470 MHz,
CDCl3) 97.9 (1F, br d, JFHˆ28 Hz), 102.7 (1F, ddd,
JFPˆ9 Hz, JFHˆ5 Hz, Jˆ5 Hz) ppm. 31P NMR
(202 MHz, CDCl3) 9.2 (m) ppm. MS (70 eV) m/z (rel.
5.6. (2-Fluorovinyl)diphenylphosphine-borane (7)
To a solution of (2,2-di¯uorovinyl)diphenylphosphine-
borane (58 mg, 0.22 mmol) in THF (2 ml) was added
LiAlH(OtBu)3 (0.33 ml, 1.0 M in THF, 0.33 mmol) at
788C. After the mixture was stirred for 3.5 h at room
temperature, the reaction was quenched with 2 M HCl.
Organic materials were extracted with ethyl acetate three
times. The combined extracts were washed with brine, and
then dried over Na2SO4. After removal of the solvent under
reduced pressure, the residue was puri®ed by thin layer
chromatography on silica gel (hexane±ethyl acetate 5:1) to
give 7 as a colorless solid (47 mg, 87%, E/Zˆ68/32).5
(E)-7: m.p. 52±548C. IR (KBr) 2400, 1625, 1490, 1440,
‡
intensity) 248 (M ±BH3; 52), 183 (20), 127 (44), 108
(100), 77 (18). HRMS calcd. for C14H11F2P 248.0565
‡
(M ±BH3); found 248.0551.
5.5. (2-Fluorovinyl)diphenylphosphine oxide (6)
1
1320, 1105, 1055, 940, 865, 825, 735, 690 cm . 1H NMR
To a solution of (2,2-di¯uorovinyl)diphenylphosphine
oxide (4, 50 mg, 0.19 mmol) in THF (2 ml) was added
LiAlH(OtBu)3 (0.21 ml, 1.0 M in THF, 0.21 mmol) at
788C. After the mixture was stirred for 10 min at
788C, the reaction was quenched with 2 M HCl. Organic
materials were extracted with ethyl acetate three times. The
combined extracts were washed with brine, and then dried
over Na2SO4. After removal of the solvent under reduced
pressure, the residue was puri®ed by thin layer chromato-
graphy on silica gel (ethyl acetate) to give 6 as a colorless
solid (43 mg, 92%, E/Zˆ93/7).
(500 MHz, CDCl3) ꢀ: 0.70±1.40 (3H, m), 5.95 (1H, dd,
JHFˆ20.9 Hz, Jˆ11.8 Hz), 7.13 (1H, ddd, JHFˆ83.2 Hz,
Jˆ11.8 Hz, JHPˆ6.9 Hz), 7.42±7.52 (6H, m), 7.59±7.64
(4H, m). 13C NMR (126 MHz, CDCl3) ꢀ: 101.3 (dd,
JCPˆ60 Hz, JCFˆ7 Hz), 129.0 (d, JCPˆ10 Hz), 129.0 (d,
JCPˆ61 Hz), 131.5 (d, JCPˆ2 Hz), 132.1 (d, JCPˆ10 Hz),
161.7 (dd, JCFˆ287 Hz, JCPˆ28 Hz). 19F NMR (470 MHz,
CDCl3)70.6(ddd,JFHˆ83 Hz,JFPˆ28 Hz,JFHˆ21 Hz)ppm.
‡
MS(70 eV)m/z230(M ±BH3;basepeak),108.HRMScalcd.
‡
for C14H12FP 230.0661 (M ±BH3); found 230.0682.
(Z)-7: IR (KBr) 2400, 1635, 1490, 1440, 1110, 1060,
1
(E)-6: IR (KBr) 1665, 1620, 1440, 1320, 1190, 1120,
1030, 740, 700 cm . 1H NMR (500 MHz, CDCl3) ꢀ: 0.80±
1
1090, 970, 720, 700 cm . 1H NMR (500 MHz, CDCl3) ꢀ:
1.75 (3H, m), 5.45 (1H, ddd, JHFˆ47.6 Hz, JHPˆ8.6 Hz,
Jˆ5.9 Hz), 7.07 (1H, ddd, JHFˆ82.7 Hz, JHPˆ20.5 Hz,
Jˆ5.9 Hz), 7.42±7.52 (6H, m), 7.68±7.73 (4H, m).
13C NMR (126 MHz, CDCl3) ꢀ: 101.2 (dd, JCPˆ54 Hz,
JCFˆ5 Hz), 128.8 (d, JCPˆ10 Hz), 128.9 (d, JCPˆ60 Hz),
131.4 (d, JCPˆ3 Hz), 132.3 (d, JCPˆ10 Hz), 158.8 (dd,
JCFˆ280 Hz, JCPˆ6 Hz). 19F NMR (470 MHz, CDCl3)
70.3 (dd, JFHˆ83, 47 Hz) ppm. MS (70 eV) m/z (rel.
6.02 (1H, ddd, JHFˆ21.6 Hz, Jˆ11.9 Hz, JHPˆ11.9 Hz),
7.07 (1H, ddd, JHFˆ83.2 Hz, Jˆ11.9 Hz, JHPˆ7.4 Hz),
7.45±7.57 (6H, m), 7.66±7.75 (4H, m). 13C NMR
(126 MHz, CDCl3) ꢀ: 104.7 (dd, JCPˆ104 Hz, JCF
ˆ
3 Hz), 128.7 (d, JCPˆ12 Hz), 131.1 (d, JCPˆ10 Hz),
132.3 (dd, JCPˆ110 Hz, JCFˆ2 Hz), 132.3 (d, JCPˆ3 Hz),
162.1 (dd, JCFˆ288 Hz, JCPˆ18 Hz). 19F NMR (470 MHz,
CDCl3) 67.0 (ddd, JFHˆ83 Hz, JFPˆ42 Hz, JFHˆ22 Hz)
ppm. 31P NMR (202 MHz, CDCl3) 22.2 (d, JPFˆ41 Hz)
‡
intensity) 230 (M ±BH3; 58), 183 (43), 152 (18), 127
(19), 108 (100). HRMS calcd. for C14H12FP 230.0661
‡
‡
ppm. MS (70 eV) m/z 246 (M ), 245, 105 (base peak), 77.
(M ±BH3); found 230.0643.
‡
HRMS calcd. for C14H12FOP 246.0609 (M ); found
246.0604. Anal. calcd. for C14H12FOP: C, 68.29; H;
4.91. Found C, 68.14; H, 5.02.
5.7. (2-Fluoro-2-phenylthiovinyl)diphenylphosphine oxide
(8)
(Z)-6: m.p. 61±638C. IR (KBr) 1630, 1440, 1180, 1120,
1
1025, 720, 700 cm . 1H NMR (500 MHz, CDCl3) ꢀ: 5.65
To a solution of (2,2-di¯uorovinyl)diphenylphosphine
oxide (4, 117 mg, 0.44 mmol) in THF (2 ml) was added
lithium benzenthiolate, generated from benzenethiol
(46 ml, 0.45 mmol) and butyllithium (0.27 ml, 1.61 M in
THF, 0.45 mmol) in THF (1 ml), at 788C. After the
(1H, ddd, JHFˆ48.3 Hz, JHPˆ7.1 Hz, Jˆ6.2 Hz), 7.05 (1H,
ddd, JHFˆ83.0 Hz, JHPˆ24.7 Hz, Jˆ6.2 Hz), 7.46±7.51
(4H, m), 7.53±7.58 (2H, m), 7.68±7.73 (4H, m).
13C NMR (126 MHz, CDCl3) ꢀ: 105.1 (dd, JCPˆ98 Hz,
JCFˆ5 Hz), 128.6 (d, JCPˆ12 Hz), 131.0 (d, JCPˆ11 Hz),
132.1 (d, JCPˆ3 Hz), 132.8 (d, JCPˆ110 Hz), 158.9 (dd,
5E/Z isomerization occurred after quenching the reaction.

J. Ichikawa et al. / Journal of Fluorine Chemistry 97 (1999) 109±114
113
mixture was stirred for 2 h at 788C, the reaction was
5.9. N-tert-butyl(diphenylphosphinoyl)acetamide (11)
quenched with phosphate buffer (pH 7). Organic materials
were extracted with ethyl acetate three times. The combined
extracts were washed with brine, and then dried over
Na2SO4. After removal of the solvent under reduced pres-
sure, the residue was puri®ed by thin layer chromatography
on silica gel (hexane±ethyl acetate 1:1) to give 8 as a
colorless solid (130 mg, 83%, E/Zˆ90/10).
To a solution of tert-butylamine (57 ml, 0.54 mmol) in
THF (2 ml) was added (2,2-di¯uorovinyl)diphenylphos-
phine oxide (4, 48 mg, 0.18 mmol) in THF (1 ml) at
08C. After the mixture was stirred for 30 min at 08C, the
reaction was quenched with phosphate buffer (pH 7).
Organic materials were extracted with ethyl acetate three
times. The combined extracts were washed with brine, and
then dried over Na2SO4. After removal of the solvent under
reduced pressure, the residue was puri®ed by thin layer
chromatography on silica gel (ethyl acetate) to give 11 as a
colorless solid (48 mg, 85%). m.p. 185±1868C. IR (KBr)
3250, 3070, 2960, 1660, 1565, 1440, 1325, 1225, 1190,
(E)-8: m.p. 89±918C. IR (KBr) 1610, 1575, 1445, 1210,
1
1
1190, 750, 700 cm . H NMR (60 MHz, CDCl3) ꢀ: 5.45
(1H, dd, JHFˆ41.0 Hz, JHPˆ6.8 Hz), 7.16±7.87 (15H, m).
13C NMR (68 MHz, CDCl3) ꢀ: 100.0 (dd, JCPˆ98 Hz,
JCFˆ16 Hz), 127.2, 128.5 (d, JCPˆ12 Hz), 129.9, 130.2,
130.9 (d, JCPˆ11 Hz), 131.9 (d, JCPˆ2 Hz), 133.2 (d,
JCPˆ109 Hz), 134.4, 169.3 (dd, JCFˆ305 Hz, JCPˆ4 Hz).
19F NMR (94 MHz, CDCl3) 98.5 (dd, JFHˆ41 Hz,
JFPˆ3 Hz) ppm. 31P NMR (202 MHz, CDCl3) 19.8 (d,
1
1130, 725, 695 cm . 1H NMR (270 MHz, CDCl3) ꢀ: 1.22
(9H, s), 3.29 (2H, d, JHPˆ12.9 Hz), 7.27 (1H, br s), 7.42±
7.58 (6H, m), 7.73±7.84 (4H, m). 13C NMR (68 MHz,
CDCl3) ꢀ: 28.4, 39.7 (d, JCPˆ60 Hz), 51.4, 128.7 (d,
‡
JPFˆ3 Hz) ppm. MS (70 eV) m/z 354 (M ; base peak),
261, 201, 77. HRMS calcd. for C20H16FOPS 354.0643
(M ); found 354.0660. Anal. calcd. for C20H16FOPS: C,
JCPˆ12 Hz), 130.7 (d, JCPˆ10 Hz), 131.7 (d, JCPˆ
‡
103 Hz), 132.2 (d, JCPˆ2 Hz), 163.7 (d, JCPˆ5 Hz). MS
‡
67.79; H, 4.55. Found C, 67.96; H, 4.69.
(70 eV) m/z 315 (M ), 300, 260, 243, 215, 201 (base peak),
77. HRMS calcd. for C18H22NO2P 315.1388 (M ); found
‡
(Z)-8: 1H NMR (60 MHz, CDCl3) ꢀ: 6.00 (1H, dd,
JHFˆ17.9 Hz, JHPˆ11.6 Hz), 7.12±7.97 (15H, m).
13C NMR (68 MHz, CDCl3; selected peaks) ꢀ: 103.3 (dd,
JCPˆ109 Hz, JCFˆ15 Hz), 168.0 (dd, JCFˆ326 Hz,
JCPˆ14 Hz). 19F NMR (94 MHz, CDCl3) 109.7 (dd,
315.1415. Anal. calcd. for C18H22NO2P: C, 68.56; H, 7.03;
N, 4.44. Found C, 68.64; H, 6.98; N, 4.38.
5.10. 1-(2-Diphenylphosphinoylacetyl)pyrrolidine (12)
‡
JFPˆ29 Hz, JFHˆ18 Hz) ppm. MS (70 eV) m/z 354 (M ),
261, 201, 77 (base peak). HRMS calcd. for C20H16FOPS
354.0643 (M ); found 354.0635.
To a solution of pyrrolidine (56 ml, 0.67 mmol) in THF
(2 ml) was added (2,2-di¯uorovinyl)diphenylphosphine
oxide (4, 59 mg, 0.22 mmol) in THF (1 ml) at 08C. After
the mixture was stirred for 10 min at 08C, the reaction was
quenched with 1 M NaOH. Organic materials were
extracted with ethyl acetate three times. The combined
extracts were washed with brine, and then dried over
Na2SO4. After removal of the solvent under reduced pres-
sure, the residue was puri®ed by thin layer chromatography
on silica gel (ethyl acetate±methanol 10:1) to give 12 as a
colorless solid (51 mg, 74%). m.p. 150±1528C. IR (KBr)
‡
5.8. [2,2-Bis(phenylthio)vinyl]diphenylphosphine oxide
(9)
To a solution of (2,2-di¯uorovinyl)diphenylphosphine
oxide (4, 84 mg, 0.32 mmol) in THF (2 ml) was added
lithium benzenthiolate, generated from benzenethiol
(77 ml, 0.75 mmol) and butyllithium (0.43 ml, 1.62 M in
THF, 0.70 mmol) in THF (1 ml), at 788C. After the
mixture was stirred for 1 h at 788C, the reaction was
quenched with phosphate buffer (pH 7). Organic materials
were extracted with dichloromethane three times. The
combined extracts were washed with brine, and then dried
over Na2SO4. After removal of the solvent under reduced
pressure, the residue was puri®ed by thin layer chromato-
graphy on silica gel (ethyl acetate) to give 9 as a colorless
solid (118 mg, 84%). m.p. 145±1478C. IR (KBr) 1520,
1
1630, 1440, 1205, 720 cm . 1H NMR (270 MHz, CDCl3)
ꢀ: 1.65±1.83 (4H, m), 3.31 (2H, t, Jˆ6.5 Hz), 3.47 (2H, t,
Jˆ6.6 Hz), 3.52 (2H, d, JHPˆ15.5 Hz), 7.41±7.57 (6H, m),
7.84±7.95 (4H, m). 13C NMR (68 MHz, CDCl3) ꢀ: 24.3,
25.9, 39.6 (d, JCPˆ61 Hz), 46.0, 47.7, 128.5 (d,
JCPˆ12 Hz), 131.2 (d, JCPˆ11 Hz), 132.0 (d, JCPˆ2 Hz),
132.4 (d, JCPˆ103 Hz), 163.5 (d, JCPˆ5 Hz). MS (70 eV)
‡
m/z 313 (M ), 215 (base peak), 201, 77. HRMS calcd. for
‡
1485, 1440, 1190, 1180, 1120, 900, 825, 750, 720,
1
C18H20NO2P 313.1232 (M ); found 313.1247. Anal. calcd.
for C18H20NO2P: C, 68.99; H, 6.43; N, 4.47. Found C,
68.77; H, 6.49; N, 4.40.
700 cm
.
1H NMR (270 MHz, CDCl3) ꢀ: 6.08 (1H, d,
JHPˆ11.6 Hz), 7.17±7.48 (16H, m), 7.65±7.79 (4H, m).
13C NMR (68 MHz, CDCl3) ꢀ: 117.4 (d, JCPˆ104 Hz),
128.4 (d, JCPˆ12 Hz), 128.7, 128.7, 128.8, 129.6, 129.6,
130.8, 131.6 (d, JCPˆ9 Hz), 131.4 (d, JCPˆ2 Hz), 134.0,
134.4 (d, JCPˆ107 Hz), 134.8, 159.7. MS (70 eV) m/z 444
Acknowledgements
We appreciate the ®nancial support by a grant from the
C.O.E. Research Fund of KIT and Central Glass Co. to J.I.
The analytical data given by Mr. Y. Wada, Mr. T. Kudo and
the Center for Instrumental Analysis KIT are greatly appre-
‡
(M ), 335, 201 (base peak), 77. HRMS calcd. for
‡
C26H21OPS2 444.0772 (M ); found 444.0796. Anal. calcd.
for C26H21OPS2: C, 70.25; H, 4.76. Found C, 70.20; H, 4.96.

114
J. Ichikawa et al. / Journal of Fluorine Chemistry 97 (1999) 109±114
[12] T. Hagiwara, K. Tanaka, T. Fuchikami, Tetrahedron Lett. 37 (1996)
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the preparation of 1.
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