On the reactions of trialkyl(trifluorovinyl)silanes with isocyanates and isothiocyanates - Expected and surprising results

Article abstract of DOI:10.1016/j.jfluchem.2013.01.011

Conditions for the addition of trialkyl(trifluorovinyl)silanes to the carbonyl- and thiocarbonyl function of commercially available isocyanates and isothiocyanates in the presence of tetramethylammonium fluoride (TMAF) to give corresponding amides of 2,3,

Full text of DOI:10.1016/j.jfluchem.2013.01.011

Journal of Fluorine Chemistry 147 (2013) 22–30
Contents lists available at SciVerse ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
On the reactions of trialkyl(trifluorovinyl)silanes with isocyanates and
isothiocyanates À Expected and surprising results
a
b
**,b
*
Natalia V. Kirij , Wieland Tyrra
, Harald Scherer c, Yurii L. Yagupolskii a, , Ingo Pantenburg ,
Dieter Naumann b
a Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya 5, UA-02094 Kiev, Ukraine
b
¨
¨
¨
Institut fu¨r Anorganische Chemie, Universitat zu Koln, Greinstraße 6, D-50939 Koln, Germany
c
¨
Institut fu¨r Anorganische und Analytische Chemie, Albert-Ludwigs-Universitat Freiburg, Albertstraße 21, D-79104 Freiburg, Germany
A R T I C L E I N F O
A B S T R A C T
Article history:
Conditions for the addition of trialkyl(trifluorovinyl)silanes to the carbonyl- and thiocarbonyl function of
commercially available isocyanates and isothiocyanates in the presence of tetramethylammonium
fluoride (TMAF) to give corresponding amides of 2,3,3-trifluoroacrylic and 2,3,3-trifluorothioacrylic
acids have been elaborated. The behaviour of the synthesized amides towards fluoride ions was studied.
The syntheses of the amides of 2,3,3,3-tetrafluoropropionic and 2,3,3,3-tetrafluorothiopropionic acids
Received 18 October 2012
Received in revised form 8 January 2013
Accepted 12 January 2013
Available online 19 January 2013
and some unexpected cyclic products with the
b
-lactam structure are described. The molecular
-lactams
Keywords:
structures of the c-hexyl amide of 2,3,3,3-tetrafluoropropionic acid and two isomers of
b
Iso(thio)cyanates
Amides
deriving from the reaction of the tert-butyl amide of 2,3,3-trifluoroacrylic acid with a fluoride source
have been elucidated by XRD measurements.
b
-Lactams
ß 2013 Elsevier B.V. All rights reserved.
Synthons
1. Introduction
compounds as well as derivatives of perfluoroacrylic acid will be of
great interest as synthons in organofluorine chemistry.
2,3,3-Trifluoroacrylic acid and its derivatives are of great
interest as synthons in organofluorine chemistry. However, the
possibilities to use them are strictly limited due to the absence of
convenient synthetic methods. The most simple, from a synthetic
point of view, method to introduce a trifluorovinyl group into an
organic molecule is via direct addition of this group to a carbonyl
function. However, this approach can be successfully used solely to
obtain perfluoroacrylic acid itself via reaction of lithium deriva-
tives of some trifluoroethylenes with carbon dioxide [1]. In
contrast, esters [2] and unsubstituted amides [3] of perfluor-
oacrylic acid were obtained in most cases from the corresponding
derivatives of trifluoropropionic acid via halogen or hydrohalo-
genic acid elimination. Commonly, trifluoropropionic acid deri-
vatives are not readily available, and their synthesis is a separate
task. On the other hand, to our knowledge, synthesis and
properties of substituted amides of perfluoroacrylic acid are not
reported in the literature. Similarly, perfluorothioacrylic acid and
its derivatives are not studied, and representatives of this class of
compounds remain unknown until now. It is probable that such
We demonstrated previously that trimethyl(trifluoromethyl)-
silane in the presence of fluoride ions can conveniently be used to
convert isocyanates and isothiocyanates into the corresponding
trifluoroacetamides and trifluorothioacetamides [4].
In extension of our systematic studies on reactions of
perfluorinated anions generated from the corresponding fluor-
oorgano silanes in the presence of fluoride ions with hetero-
cumulenes of the type R–X = Y = Z, with X = N, S; Y = C, S; Z = O, S in
different combinations, we now report on the reactions of
isocyanates and isothiocyanates with trialkyl(trifluorovinyl)si-
lanes (Alk3SiCF = CF2, Alk = Me, Et) in the presence of tetramethy-
lammonium fluoride ([Me4N]F) and the conversion of the
synthesized amides of 2,3,3-trifluoroacrylic and 2,3,3-trifluor-
othioacrylic acids under the influence of fluoride ions.
2. Results and discussion
We found that the reaction of equimolar quantities of the
isocyanates 1a–c, Alk3SiCF55CF2 (Alk = Me, Et) and [Me4N]F in
dimethoxyethane (DME) at À60 8C proceeds selectively within 2 h;
protolysis of the intermediates led to the formation of amides of
trifluoroacrylic acid 2a–c in 60–70% yields (Scheme 1).
Reaction intermediates in all cases were tetramethylammo-
nium salts of the N-substituted amides of 2,3,3-trifluoroacrylic
acid which were directly formed after mixing of the reagents. Upon
* Corresponding author. Tel.: +38 044 5590349; fax: +38 044 5732643.
** Co-corresponding author.
E-mail address: yagupolskii@ioch.kiev.ua (Y.L. Yagupolskii).
0022-1139/$ – see front matter ß 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jfluchem.2013.01.011

N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
23
DME
60 C
H[BF ] Et O
4
2
o
o
O
O
DME, 60 C to r.t.
[Me N][BF ]
+
R
N C O + Alk SiCF CF + [Me N]F
CF =CF
[Me N]
CF =CF
3
2
4
2
4
2
NHR
Alk SiF
4
4
NR
3
1a-c
2a-c
R = Ad (a), c-C H (b), t-Bu (c); Alk = Me, Et
6
11
Scheme 1. Synthesis of 2a–c.
treatment of these salts with H[BF4]ÁEt2O at À60 8C, they were
converted selectively into the corresponding amides. We observed
no significant difference upon usage of trimethyl- and triethyl(tri-
fluorovinyl)silanes.
Compounds 5a,b were isolated as colourless stable solids in 62%
and 65% yields, respectively, and were characterized by 1D and 2D
NMR spectroscopic methods as well as EI mass spectra. Elemental
analyses supported the compositions. Crystals of the amide 5b
suitable for XRD analysis were grown from pentane-hexane
mixtures. The molecular structure of 5b is depicted in Fig. 1.
Crystallographic data are summarized in the experimental part.
Selected bond lengths and angles are given in the caption of Fig. 1.
Compounds 2a–c were isolated as colourless stable solids and
were characterized by 1H, 19F, 13C NMR and mass spectra.
Elemental analyses supported the compositions. It should be
noted that the reaction of ethyl- and phenylisocyanate with the
system Alk3SiCF55CF2/FÀ (Alk = Me, Et) under similar conditions
proceeded less selectively and led to product mixtures. Unfortu-
nately, we failed to isolate the pure amides, but their formation
was monitored by 19F NMR spectroscopy comparing the chemical
shifts and couplings with those of the isolated products.
In order to extend this reaction to derivatives of 2,3,3-
trifluorothioacrylic acid, we investigated the possibility of
synthesising so far unknown amides of trifluorothioacrylic acid.
The isothiocyanates 3a–c react with the system Alk3SiCF55CF2/FÀ,
in a similar manner as described for 2a–c, to yield the amides of
trifluorothioacrylic acid 4a–c (Scheme 2).
2.1. Description of the molecular structure of 5b
¯
Compound 5b crystallizes in the triclinic space group P1 (no. 2)
with two crystallographically independent molecules. All bond
lengths and angles do not deviate from expectations for such a
molecule. The carbon–oxygen distances of C13–O131 (123.3(3)
pm) and C23–O231 (123.6(3) pm) clearly imply the character of a
C55O double bond. Also the angles around C13 (N14) and C23 (N24)
varying around 120 Æ 58 describe a typical arrangement for an amide
of a carboxylic acid.
The thioamide 4a was obtained using column chromatography
in 50% yield as a yellow liquid. Its composition was elucidated by
NMR spectroscopic methods, mass spectra and elemental analysis.
The thioamides 4b and 4c, initially formed in 60–70% yields as
monitored by 19F NMR spectroscopic means (relative to 1,4-
difluorobenzene) exhibited to be less stable. Upon attempted
isolation of compound 4b using column chromatography, a great
amount of 4b decomposed finally leading to 15% of the neat
product which was identified by NMR spectroscopic techniques
and supported by satisfactory elemental analyses; amide 4c could
not be isolated and is proposed solely on its characteristic 19F NMR
spectrum in comparison with those of 4a and b. Compounds 4a,b
are stable in a dry argon atmosphere at À30 8C for several weeks
exhibiting no visible decomposition, while in solution all
thioamides completely decomposed within some days.
Earlier, we showed that trifluorovinyl containing alcohols react
with fluoride anions via addition to the C55C double bond [5].
Next, we investigated the reactions of the amides of 2,3,3-
trifluoroacrylic and 2,3,3-trifluorothioacrylic acids with tetra-
methylammonium fluoride. Compounds 2a,b react with one
equivalent of [Me4N]F in DME in a temperature range from
À30 8C to room temperature to form the amides of 2,3,3,3-
tetrafluoropropionic acid 5a,b (Scheme 3).
In both independent molecules, the cyclohexyl groups reside in
the chair conformation. In the packing, both molecules are
connected to infinite chains along the crystallographic a-axis with
alternating cyclohexyl groups exhibiting two intermolecular
alternating graph set motifs C(4) [6] for hydrogen bridges
following D–H (N14–H5) 82.5(22) pm; HÁÁÁA (H5ÁÁÁO231)
208.9(24) pm; DÁÁÁA (N14ÁÁÁO231) 288.2(9) pm; D–HÁÁÁA
160.9(20)8 and D–H (N24–H8) 79.6(25) pm; HÁÁÁA (H8ÁÁÁO131)
213.9(23) pm; DÁÁÁA (N24ÁÁÁO131) 289.7(15) pm; D–HÁÁÁA
159.4(20)8.
Surprisingly, the analogous reaction of the amide 2c with
tetramethylammonium fluoride afforded not only the expected
amide of N-tert-butyl-2,3,3,3-tetrafluoropropanamide 5c but the
unexpected
b-lactams 6 and 7 (Scheme 5).
The amount of tetramethylammonium fluoride was found to be
critical for the products formation ratio. Thus, compound 2c
reacted with [Me4N]F in a molar ratio of 1:1 in DME in a
temperature range between À30 8C to 20 8C to form the
unprecedented mixture of the amide 5c and the cyclic products
6 and 7 in a 9:1 ratio. Using a catalytic amount of tetramethy-
lammonium fluoride caused lower amount of the amide 5c (60%)
but a concomitant increase of the formation of the products 6 and 7
(40%) (ratio approximately 3:2).
It has to be pointed out that amides of 2,3,3-trifluoroacrylic acid
2a,b can be used without prior isolation in a reaction with [Me4N]F
opening an easy and convenient one-pot synthesis route to obtain
of the amides 5a,b in high yields (Scheme 4). A mechanistic
explanation how the [Me4N]-cation serves as a proton source
cannot be given.
Most probably, attack of a fluoride ion at the double bond of 2c
initially affords the anion 8. It should be noted that the
trifluorovinyl group of compound 2c is highly reactive toward
nucleophiles. The nucleophilic addition of the anion 8 to the
trifluorovinyl unit of 2c, which leads to the formation of
intermediates of type A, is accompanied by fluoride anion
DME, 60 oC
H[BF4] Et2O
DME
S
30 oC to r.t.
O
O
R N C S + Alk3SiCF CF2 + [Me4N]F
CF2=CF
CF3CFH
5a,b
+ [Me4N]F
CF2=CF
Alk3SiF
[Me4N][BF4]
NHR
NHR
NHR
3a-c
4a-c
2a,b
R = Ad (a), c-C6H11 (b)
R = c-C6H11 (a), Et (b), Ph (c); Alk = Me, Et
Scheme 2. Synthesis of 4a–c.
Scheme 3. Synthesis of 5a,b.

24
N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
o
o
DME, 60
C
DME, 30
[Me N]F
C
O
O
H[BF ] Et O
4
2
4
R
N C O + Et SiCF CF + [Me N]F
3 2 4
CF =CF
CF CFH
2
3
Et SiF
[Me N][BF ]
3
NHR
NHR
4
4
1a,b
R = Ad (a), c-C H (b)
2a,b
5a,b
6
11
Scheme 4.
(intermediates of type B) and hydrofluoric acid elimination with
formation of the products 6 and 7 (Scheme 6).
P21/c (no. 14) both with 4 molecules per unit cell. Despite the fact
of being stereoisomers, molecular structures of both do not deviate
significantly from each other. Angular sums around the 4-
membered ring are nearly identical together with bond lengths
and angles (cp. captions to Figs. 2 and 3) and are in good agreement
with the rare examples of structurally characterized compounds
bearing an alkylidene azetidinone moiety [7–12]. The steric
demand of both tert-butyl groups, when residing in the same
direction as in isomer 7, twists the amide moiety out of the plane,
Compounds 5c, 6 and 7 were isolated as colourless stable solids
using column chromatography and were identified by NMR
spectroscopic techniques, mass spectra and elemental analyses.
Crystals suitable for X-ray analysis of 6 and 7 were grown from
pentane solution and pentane-dimethoxyethane mixture, respec-
tively. The molecular structures of 6 and 7 are depicted in Figs. 2
and 3. Crystallographic data are summarized in the experimental
part. Selected bond lengths and angles are given in the caption of
the corresponding Fig.
formed by the
b-lactam and the unsaturated chain, by approxi-
mately 308. In derivative 6, coplanarity of the whole unit is evident
as also observed in the molecular structure of 3-(1-hydroxyethyl)-
4-[2-ethoxycarbonyl-(Z)-methylidene]-azetidin-2-one [8,9].
Identical structures in solution and in the solid state for both
compounds have been established by NMR spectroscopic methods
on the basis of 1D and 2D experiments (H,C{19F} HSQC; H,C{19F}
2.2. Comparative description of the molecular structures of 6 and 7
Compound 6 crystallizes in the acentric orthorhombic space
group Pca21 (no. 29), compound 7 in the monoclinic space group
O
O
DME
30 C to r.t.
O
F
CF
3
o
N
H
F
F
O
N
H
N
H
N
+
+
O
CF CFH
+ [Me N]F
3
4
O
N
H
N
F
F
F
F
CF
3
2c
5c
6
7
Scheme 5. Synthesis of 5c, 6 and 7.
O
N
F
H
F
F
F
F
2c
F
O
F
N
H
F
-
F-
+
H
N
O
F
F
2c
8
F
F
F
F
F
F
O
O
F
F
H
F
F
_
F-
_
HF
F
N
H
N
H
F
N
F
O
O
N H
A
B
O
O
F CF3
N
N
H
N
H
N
+
O
O
F
F
CF3
6
7
Scheme 6. Probable mechanism for the formation of 6 and 7.

N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
25
Fig. 1. Molecular structure of N-cyclohexyl-2,3,3,3-tetrafluoropropanamide (5b) with the corresponding numbering scheme depicted along the crystallographic b-axis (top);
graph set motif C(4) (bottom). Selected bond lengths (pm) and angles (8): C13–O131 123.3(3); C15(ring)–N14 146.9(16); N14–C13 132.2(14), C13–C12 152.8(17); C12–C11
150.7(6); C15–N14–C13 122.74(16); N14–C13–C12 116.54(16); N14–C13–O131 123.37(15); O131–C13–C12 117.09(15); C23–O231 123.6(3); C25(ring)–N24 146.2(6);
N24–C23 132.6(11); C23–C22 151.4(7); C22–C21 151.1(16); C25–N24–C23 122.92(16); N24–C23–C22 117.21(15); N24–C23–O231 125.58(15); O231–C23–C22 117.21(14).

26
N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
Fig. 2. Molecular structure of N-tert-butyl-2-[1-tert-butyl-3-fluoro-4-oxo-3-trifluoromethyl-azetidin-(2Z)-ylidene]-2-fluoro-acetamide (6) with the corresponding
numbering scheme. Selected bond lengths (pm) and angles (8): C31–O31 121.8(6); C71–O71 122.2(6); C5–C4 130.7(6); C4–C3 149.4(7); C3–N2 132.9(6); N2–C1
149.3(6); ring; C5–C6 141.3(6); C7–C6 135.8(7); C7–N6–C5 93.5(5); N6–C5–C8 89.8(4); C5–C8–C7 83.9(4); C8–C7–C6 91.7(4); angular sum (4-membered ring) 359.3.
Torsion angle C5–C4–C3–O31 À5.23(83).
HMBC; F,C{1H} HSQC; F,C{1H} HMBC; H,H NOESY; F,F COSY; F,F
NOESY; F,H HOESY). Some specific features have to be mentioned.
In the 19F NMR spectrum of the Z-isomer (6), the signal of the CF3
tert-butyl group attached to the
b
-lactam (shortest d(F,H) ꢀ 226
pm; shortest d(F,C) ꢀ 306 pm in the solid state) together with the
rigidity of alkylidene azetidinone kernel effect long-range
(‘‘through space’’) couplings of 5JF,C = 7 Hz and 6JF,H = 0.9 Hz. These
phemonena are frequently observed for compounds showing
similar spatial arrangements [13,14].
In the 19F NMR spectrum of the E-isomer (7), signals of all
fluorine groups are split into more or less complex multiplets.
3
group is split into a doublet (À74.2, JF,F = 10.0 Hz), that of the
3
4
adjacent fluorine atom (À173.9, JF,F = 10 Hz; JF,F ꢀ 1 Hz) into a
quartet of doublets due to the coupling with the olefinic fluorine
atom which itself occurs as a broadened singlet (À139.6, D1/
2 ꢀ 7 Hz). The spatial vicinity of the olefinic fluorine atom and the
Fig. 3. Molecular structure of N-tert-butyl-2-[1-tert-butyl-3-fluoro-4-oxo-3-trifluoromethyl-azetidin-(2E)-ylidene]-2-fluoro-acetamide (7) with the corresponding
numbering scheme. Selected bond lengths (pm) and angles (8): C31–O31 121.0(4); C71–O71 121.0(4); C5–C4 132.5(4); C4–C3 150.1(4); C3–N2 132.9(4); N2–C1
148.4(4); ring; C5–C6 142.5(4); C7–C6 138.4(4); C7–N6–C5 93.5(2); N6–C5–C8 90.8(2); C5–C8–C7 84.8(2); C8–C7–C6 91.0(2); angular sum (4-membered ring) 360.1.
Torsion angle C5–C4–C3–O31 +28.26(56).

N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
27
o
o
DME, 60 C
H[BF ] Et O
DME, 30
[Me N]F
C
S
S
4
2
4
R N C S + Et SiCF CF + [Me N]F
CF =CF
CF CFH
3
2
4
2
3
Et SiF
3
NHR
NHR
[Me N][BF ]
4
4
3a-c
R = c-C H (a), Et (b), Ph (c)
4a-c
9a-c
6
11
Scheme 7. Synthesis of 9a–c.
While the fluorine atom directly bond to the
quartet of doublets (À177.6, JF,F = 10.9 Hz; JF,F = 6.6 Hz) and the
b
-lactam exhibits a
4. Experimental
General: All reactions were carried out in
3
4
3
a
dry argon
CF3 group
a
doublet of doublets (À76.3, JF,F = 10.9 Hz;
5JF,F = 13.6 Hz (!!!)), the resonance of the olefinic fluorine atom
atmosphere by using Schlenk techniques. The following products
were synthesized according to literature procedures:
Me3SiCF55CF2 [1a], Et3SiCF55CF2 [1a], [Me4N]F [18]. All solvents
were purified according to literature procedures [19]. 1H, 13C and
19F NMR were recorded with Bruker AvanceII 300 and Avance 400
spectrometers. Chemical shifts are referenced relative to the
external standards Me4Si (1H and 13C) and CCl3F (19F). Mass spectra
(EI; 20 eV) were obtained with a Finnigan MAT 95 spectrometer.
Melting points were measured in one-end-open glass capillaries
and are uncorrected. Column chromatography was carried out by
using 60–240 mesh silica gel at atmospheric pressure. C, H, N and F
analyses were performed with HEKAtech Euro EA 3000 and
Analytikjena Spekol 1100 instruments.
5
4
4
(À143.4, JF,F = 13.6 Hz (!!!); JF,F = 6.6 Hz; JF,H = 4.5 Hz (!!!)) is
split into a quartet of doublets of an additional doublet due to the
coupling with the proton of the adjacent amino group. The
5
4
exceptional large JF,F and JF,H couplings may again be attributed
to the spatial vicinity of those nuclei. However, the NH resonance is
observed only as a broadened singlet (D1/2 ꢀ 15 Hz) in the 1H NMR
spectrum.
The b-lactam structure is of great interest as a fundamental and
versatile building block in the design and synthesis of several
biologically active compounds. It has widely been used to obtain
fundamental antibacterial products (b-lactam antibiotics) [15],
unusual peptide derivatives [16] and enzymatic inhibitors of
different serine proteases [17]. It should be noted that fluorinated
compounds 6 and 7 obtained in the course of research are of great
Data collection for X-ray structure determination was per-
formed on STOE IPDS I/II diffractometers using graphite-mono-
chromated Mo–Ka radiation. The data were corrected for Lorentz
practical interest. The procedure described above opens
a
and polarization effects. A numerical absorption correction based
on crystal-shape optimisation was applied for all data [20]. The
programs used in this work are Stoe’s X-Area [21], including X-RED
and X-Shape for data reduction and absorption correction [22], and
the WinGX suite of programs [23], including SIR-92 [24] and
SHELXL-97 [25] for structure solution and refinement. The
hydrogen atoms were placed in idealized positions and con-
strained to ride on their parent atom. The last cycles of refinement
included atomic positions for all the atoms, anisotropic thermal
parameters for all the non-hydrogen atoms and isotropic thermal
parameters for all of the hydrogen atoms. Crystallographic data for
the structures have been deposited with the Cambridge Crystallo-
graphic Data Centre as supplementary publication nos. CCDC-
873761 (5b), CCDC-873759 (6), and CCDC-873760 (7). Copies of
the data can be obtained, free of charge, on application to CHGC, 12
Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223 336033 or
deposit@ccdc.cam.ac.uk).
convenient alternative route to cyclic products with the -lactam
motif directly accessible from relative inexpensive isocyanates as
starting materials.
b
We further investigated the reaction of amides of the 2,3,3-
trifluorothioacrylic acid and tetramethylammonium fluoride.
In a similar manner as described for the synthesis of 5a,b, the
unstable amides 4a–c, obtained without prior isolation, reacted
with one equivalent [Me4N]F in DME in the temperature range
from À30 8C to room temperature to form the amides of the
2,3,3,3-tetrafluorothiopropionic acid 9a–c (Scheme 7).
The thioamides 9a–c were obtained as yellow liquids using
column chromatography. Their compositions were elucidated by
NMR spectroscopic methods, mass spectra and elemental
analyses.
Taking into consideration the availability of the reagents we
have used together with the good yields of the final products, the
method presented opens an attractive alternative route to obtain
amides of 2,3,3,3-tetrafluoropropionic and 2,3,3,3-tetrafluorothio-
propionic acids which again may become sources of new and
innovative synthetic procedures.
4.1. General procedure for the synthesis of 2,3,3-trifluoroacrylamides
2
To a solution of isocyanate 1 (5 mmol) in dimethoxyethane
(DME) (25 mL) at À60 8C was added R3SiCF = CF2 (R = Me, Et)
(6.25 mmol) and [Me4N]F (0.51 g, 5.5 mmol). The mixture was
stirred for 2 h at À55 Æ 5 8C and then HBF4ÁEt2O (0.81 g, 5 mmol) was
added. The mixture formed was allowed to reach room temperature
and stirred for 1 h. The solvent and all other volatile materials were
evaporated in vacuo and the product was extracted into hexane. The
precipitated [Me4N][BF4] was filtered and the solvent was removed in
vacuo. The amides 2 were purified by crystallization from pentane or
by sublimation.
3. Conclusions
In summary, a new, convenient and efficient synthesis of
amides of 2,3,3-trifluoroacrylic 2 and 2,3,3-trifluorothioacrylic
acids 4 has been developed by means of the direct addition of the
trifluorovinyl group – generated from trialkyl(trifluorovinyl)si-
lanes in the presence of tetramethylammonium fluoride – to
easily available or commercial substances such as organic
isocyanates and isothiocyanates. The formation of compounds
2 and 4 opens an easy and convenient route to the synthesis of
amides of 2,3,3,3-tetrafluoropropionic 5 and 2,3,3,3-tetrafluor-
othiopropionic 9 acids. It should also be noted that the reaction of
4.2. N-1-Adamantyl-2,3,3-trifluoroacrylamide (2a)
2c and [Me4N]F proceeds to yield the fluorine containing
lactams 6 and 7 which were fully characterized including the solid
b-
Yield 0.86 g (66%), white solid, mp 114–115 8C. 1H NMR
(300.13 MHz, CDCl3):
d 1.7 (broad s, 6H, Ad), 2.06 (broad s, 6H,
state structures.

28
N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
Ad), 2.11 (broad s, 3H, Ad), 5.75 (broad s, 1H, NH). 13C
55CF), 156.6 (ddd, 1JC,F = 295 Hz, 1JC,F = 302 Hz, 2JC,F = 48 Hz, 55CF2),
2
3
3
(100.623 MHz, CDCl3):
d
29.4 (3C, CH), 36.2 (3C, CH2), 41.5 (3C,
179.4 (ddd, JC,F = 15 Hz, JC,F = 8.3 Hz, JC,F = 4.6 Hz, CS). 19F
CH2), 52.9 (C), 124.5 (ddd, 1JC,F = 248 Hz, 2JC,F = 32 Hz, 2JC,F = 18 Hz,
55CF–), 156.0 (ddd, 1JC,F = 298 Hz, 1JC,F = 301 Hz, 2JC,F = 41 Hz,55CF2),
(282.4 MHz, CDCl3):
d
À85.6 (dd, JF,C = 295 Hz, JF,F = 14 Hz,
1
2
3JF,Fcis = 35 Hz, 55CFF), À95.9 (dd, JF,C = 302 Hz, JF,F = 14 Hz,
1 2
2
3
3
156.5 (ddd, JC,F = 23 Hz, JC,F = 6.4 Hz, JC,F = 5.5 Hz, CO). 19F
3JF,Ftrans = 116 Hz,
55CFF),
À171.8
(dd,
1JF,C = 246 Hz,
1
2
3
(282.4 MHz, CDCl3):
d
À87.5 (dd, JF,C = 298 Hz, JF,F = 32 Hz,
3JF,Ftrans = 116 Hz, JF,Fcis = 35 Hz, 55CF–). MS (EI): m/z (%) = 223
(100) [M]+. Anal. Calcd for C9F3H12NS (223.27): C 48.42, F 25.53, H
5.42, N 6.27. Found: C 48.33, F 25.48, H 5.39, N 6.22.
3JF,Fcis = 35 Hz, 55CFF), À100.8 (dd, JF,C = 301 Hz, JF,F = 32 Hz,
1
2
3JF,Ftrans = 113 Hz,
55CFF),
À181.1
(dd,
1JF,C = 248 Hz,
3
3JF,Ftrans = 113 Hz, JF,Fcis = 35 Hz, 55CF–) ppm. MS (EI): m/z
(%) = 259 (90) [M]+. Anal. Calcd for C13F3H16NO (259.27): C
60.22, F 21.98, H 6.22, N 5.4. Found: C 60.14, F 21.91, H 6.17, N 5.34.
4.7. N-Ethyl-2,3,3-trifluorothioacrylamide (4b)
Yield 0.13 g (15%), yellow liquid, Rf 0.17 (hexane/diethyl ether
3
4.3. N-Cyclohexyl-2,3,3-trifluoroacrylamide (2b)
9:1). 1H NMR (300.13 MHz, CDCl3):
d
1.32 (t, JH,H = 7.2 Hz, 3H,
CH3), 3.76 (qd, 3JH,H = 7.2 Hz, 3JH,H = 5.2 Hz, 2H, CH2), 7.72 (broad s,
1H, NH). 13C (75.47 MHz, CDCl3):
12.9 (CH3CH2), 39.6 (CH3CH2),
Yield 0.71 g (69%), white solid, mp 103–104 8C. 1H NMR
d
(300.13 MHz, CDCl3):
C6H11), 1.72 (m, 2H, c-C6H11), 1.94 (m, 2H, c-C6H11), 3.85 (m, 1H, c-
C6H11), 6.11 (broad s, 1H, NH). 13C (100.623 MHz, CDCl3):
25.0
(2C, CH2), 25.6 (CH2), 33.0 (2C, CH2), 48.5 (CH), 124.7 (ddd,
d
1.28 (m, 5H, c-C6H11), 1.63 (m, 1H, c-
128.1 (55CF), 155.8 (55CF2), 179.8 (CS). 19F (282.4 MHz, CDCl3):
d
À85.2 (dd, 1JF,C = 297 Hz, 2JF,F = 15 Hz, 3JF,Fcis = 35 Hz, 55CFF), À95.4
1
2
3
d
(dd, JF,C = 300 Hz, JF,F = 15 Hz, JF,Ftrans = 116 Hz, 55CFF), À170.7
(dd, 1JF,C = 248 Hz, 3JF,Ftrans = 116 Hz, 3JF,Fcis = 35 Hz,55CF–). MS (EI):
m/z (%) = 169 (100) [M]+. Anal. Calcd for C5F3H6NS (169.18): C
35.50, F 33.69, H 3.57, N 8.28. Found: C 35.44, F 33.65, H 3.54, N
8.23.
2
2
1JC,F = 248 Hz, JC,F = 31 Hz, JC,F = 18 Hz, 55CF–), 156.2 (ddd,
1
2
1JC,F = 297 Hz, JC,F = 301 Hz, JC,F = 42 Hz, 55CF2), 156.9 (ddd,
2JC,F = 22 Hz, JC,F = 6.5 Hz, JC,F = 5.4 Hz, CO). 19F (282.4 MHz,
3
3
1
2
3
CDCl3):
d
À87.7 (dd, JF,C = 297 Hz, JF,F = 32 Hz, JF,Fcis = 35 Hz,
1 2 3
55CFF), À100.6 (dd, JF,C = 301 Hz, JF,F = 32 Hz, JF,Ftrans = 114 Hz,
4.8. N-Phenyl-2,3,3-trifluorothioacrylamide (4c)
1
3
3
55CFF), À183.7 (dd, JF,C = 248 Hz, JF,Ftrans = 114 Hz, JF,Fcis = 35 Hz,
55CF). MS (EI): m/z (%) = 207 (10) [M]+, 126 (100) [MÀC2F3]+. Anal.
Calcd for C9F3H12NO (207.2): C 52.17, F 27.51, H 5.84, N 6.76.
Found: C 52.11, F 27.45, H 5.79, N 6.72.
19F (282.4 MHz, DME):
d
= À91.29 (dd, 1JF,C = 297 Hz,
2JF,F = 25 Hz, JF,Fcis = 35 Hz, 55CFF), À99.73 (dd, JF,C = 301 Hz,
3
1
2JF,F = 25 Hz, JF,Ftrans = 117 Hz, 55CFF), À167.98 (dd, JF,C = 249 Hz,
3
1
3
3JF,Ftrans = 117 Hz, JF,Fcis = 35 Hz, 55CF–).
4.4. N-tert-Butyl-2,3,3-trifluoroacrylamide (2c)
4.9. General procedure for the synthesis of 2,3,3,3-
Yield 0.59 g (65%), white solid, mp 66–67 8C. 1H NMR
tetrafluoropropionamides 5
(300.13 MHz, CDCl3):
d
1.43 (s, 9H, tert-Bu), 5.9 (broad s, 1H,
28.7 (3C, CH3), 52.2 (C), 124.6
NH). 13C (100.623 MHz, CDCl3):
d
Method A: To a solution of isocyanate 1 (5 mmol) in
1
2
2
(ddd, JC,F = 250 Hz, JC,F = 32 Hz, JC,F = 19 Hz, 55CF), 155.9 (ddd,
dimethoxyethane (DME) (25 mL) at À60 8C R3SiCF = CF2 (R = Me,
Et) (6.25 mmol) and [Me4N]F (0.51 g, 5.5 mmol) was added. The
mixture was stirred for 2 h at À55 Æ 5 8C and then HBF4ÁEt2O (0.81 g,
5 mmol) was added. The reaction mixture was stirred for 30 min at
À35 Æ 5 8C and [Me4N]F (0.46 g, 5 mmol) was added. The mixture
formed was stirred for 1 h at À35 Æ 5 8C and then allowed to reach
room temperature. All volatile components were removed in vacuo
and the product was extracted into hexane. The precipitated
[Me4N][BF4] was filtered and the solvent was evaporated in vacuo.
The amides 5 were purified by crystallization from pentane or
sublimation.
1JC,F = 299 Hz, JC,F = 301 Hz, JC,F = 43 Hz, 55CF2), 156.8 (ddd,
2JC,F = 21 Hz, JC,F = 6.5 Hz, JC,F = 5.5 Hz, CO). 19F (282.4 MHz,
1
2
3
3
1
2
3
CDCl3):
d
À87.6 (dd, JF,C = 299 Hz, JF,F = 31 Hz, JF,Fcis = 35 Hz,
1 2 3
55CFF), À100.7 (dd, JF,C = 301 Hz, JF,F = 31 Hz, JF,Ftrans = 114 Hz,
1
3
3
55CFF), À181.5 (dd, JF,C = 250 Hz, JF,Ftrans = 114 Hz, JF,Fcis = 35 Hz,
55CF–). MS (EI): m/z (%) = 181 (10) [M]+, 166 (100) [MÀCH3]+. Anal.
Calcd for C7F3H10NO (181.16): C 46.41, F 31.46, H 5.56, N 7.73.
Found: C 46.34, F 31.41, H 5.52, N 7.67.
4.5. General procedure for the synthesis of 2,3,3-
trifluorothioacrylamides 4
4.10. N-1-Adamantyl-2,3,3,3-tetrafluoropropionamide (5a)
Yield 0.87 g (62%), white solid, mp 105 8C. 1H NMR
To a mixture of isothiocyanate 3 (5 mmol) and [Me4N]F (0.51 g,
5.5 mmol) in dimethoxyethane (DME) (30 mL) at À60 8C was
added Et3SiCF = CF2 (1.23 g, 6.25 mmol) dropwise over a period of
30 min. The mixture was stirred for 90 min at À55 Æ 5 8C and then
HBF4ÁEt2O (0.81 g, 5 mmol) was added. The mixture formed was
allowed to warm to the room temperature and stirred for 1 h. All
volatile components were removed in vacuo and the product was
extracted into hexane. The precipitated [Me4N][BF4] was filtered and
the solvent was evaporated in vacuo. The thioamides 4 were purified
by silica gel column chromatography.
(300.13 MHz, CDCl3):
Ad), 2.13 (broad s, 3H, Ad), 5.02 (dq, JH,F = 46.9 Hz, JH,F = 6.5 Hz,
1H, CHF), 5.98 (broad s, 1H, NH). 13C (75.47 MHz, CDCl3):
29.4 (3C,
d 1.71 (broad s, 6H, Ad), 2.05 (broad s, 6H,
2
3
d
CH), 36.1 (3C, CH2), 41.2 (3C, CH2), 53.1 (C), 85.4 (CFH), 120.8 (CF3),
1
159.7 (CO). 19F (282.4 MHz, CDCl3):
d
À76.1 (dd, JF,C = 282 Hz,
3
1
3JF,F = 10.9 Hz, JF,H = 6.5 Hz, CF3), À198.5 (dqd, JF,C = 203 Hz,
2JF,H = 46.9 Hz, JF,F = 10.9 Hz, JF,H = 3.8 Hz, CFH). MS (EI): m/z
(%) = 279 (90) [M]+. Anal. Calcd for C13F4H17NO (279.28): C 55.91, F
27.21, H 6.14, N 5.02. Found: C 55.84, F 27.17, H 6.11, N 4.99.
3
4
4.6. N-Cyclohexyl-2,3,3-trifluorothioacrylamide (4a)
4.11. N-Cyclohexyl-2,3,3,3-tetrafluoropropionamide (5b)
Yield 0.55 g (49%), yellow liquid, Rf 0.15 (hexane/benzene 4:1).
1H NMR (400.14 MHz, CDCl3):
d
1.25 (m, 3H, c-C6H11), 1.38 (m, 2H,
Yield 0.74 g (65%), white solid, mp 96 8C (lit. 89–90 8C [26]). 1H
c-C6H11), 1.64 (m, 1H, c-C6H11), 1.73 (m, 2H, c-C6H11), 2.05 (m, 2H,
c-C6H11), 4.44 (m, 1H, c-C6H11), 7.45 (broad s, 1H, NH). 13C
NMR (400.13 MHz, CDCl3): d 1.25 (m, 5H, c-C6H11), 1.61 (m, 1H, c-
C6H11), 1.69 (m, 2H, c-C6H11), 1.88 (m, 2H, c-C6H11), 3.81 (m, 1H, c-
(100.623 MHz, CDCl3):
d
24.9 (2C, CH2), 25.7 (CH2), 31.7 (2C, CH2),
C6H11), 5.02 (dq, 2JH,F = 46.4 Hz, 3JH,F = 6.5 Hz, 1H, CHF), 6.43 (broad
1
2
2
6
53.0 (CH), 128.8 (ddd, JC,F = 246 Hz, JC,F = 21.5 Hz, JC,F = 22.6 Hz,
s, 1H, NH). 13C (100.61 MHz, CDCl3):
d
25.5 (d, JC,F = 3.7 Hz, 2C,

N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
29
5
CH2), 26.1 (CH2), 33.4 (d, JC,F = 11.5 Hz, 2C, CH2), 49.5 (CH), 86.2
were symmetrically independent; Rint = 0.0955; F(000) = 712;
= 0.121 mmÀ1. Orthorhombic, Pca21 (no. 29), a = 1073.7(3),
b = 1819.2(4), c = 902.6(2) pm, V = 1763.0(7) 106 pm3, Z = 4; R
values: R1/wR2 for 1223 reflections with [I0 > 2 (I0)]: 0.0585/
1
2
1
(dq, JC,F = 203 Hz, JC,F = 33 Hz, CFH), 121.5 (qd, JC,F = 282 Hz,
2JC,F = 25 Hz, CF3), 161.0 (d, JC,F = 19 Hz, CO). 19F (376.4 MHz,
m
2
1
3
3
CDCl3):
d
À76.2 (dd, JF,C = 282 Hz, JF,F = 10.8 Hz, JF,H = 6.5 Hz,
s
1
2
3
CF3), À201.9 (dqdd, JF,C = 203 Hz, JF,H = 46.4 Hz, JF,F = 10.8 Hz,
4JF,H = 2.6 Hz, 6JF,H = 1.3 Hz, CFH). MS (EI): m/z (%) = 227 (10) [M]+,
146 (100) [MÀC2F3]+. Anal. Calcd for C9F4H13NO (227.21): C 47.58,
F 33.45, H 5.77, N 6.16. Found: C 47.51, F 33.39, H 5.71, N 6.12.
Crystal data of 5b: C4H13F4NO, 227.20 g molÀ1. Diffractometer
0.1074, for all data: 0.1862/0.1428; Sall = 0.824, Flackx = À0.1 (15).
4.14. N-tert-butyl-2-[1-tert-butyl-3-fluoro-4-oxo-3-
trifluoromethyl-azetidin-(2E)-ylidene]-2-fluoro-acetamide (7)
IPDS-II, Stoe Darmstadt; Mo–Ka
(graphite monochromator,
Yield 0.26 g (15%), white solid, mp 83–84 8C, Rf 0.35 (hexane/
À
a
l
= 71.073 pm); T = 170(2) K; 2
08 ꢁ ꢁ 548, = 908, Dv = 28, 117 images; À13 ꢁ h ꢁ 13,
calc = 1.401 g cmÀ3; 13,636 mea-
u
max = 59.58; 08 ꢁ
v
ꢁ 1808,
w
= 08,
diethyl ether 19:1). 1H NMR (400.13 MHz, CDCl3):
d 1.44 (s, 9H, CH3
v
w
(t-Bu) amide), 1.62 (s, 9H, CH3 (t-Bu) lactam), 6.16 (broad s, D1/
À15 ꢁ k ꢁ 15, À15 ꢁ l ꢁ 15;
r
2 ꢀ 15 Hz, 1H, NH). 13C (100.61 MHz, CDCl3):
d 28.2 (3C, CH3 (t-Bu)
sured reflections of which 5916 were symmetrically independent;
amide), 28.5 (s, 3C, CH3 (t-Bu) lactam), 52.0 (C (t-Bu) amide), 60.6
(C (t-Bu) lactam), 97.5 (CF(CF3)), 120.1 (CF3), 127.0 (FC = C lactam),
134.8 (FC = C lactam), 157.4 (CO amide), 157.6 (CO lactam). 19F
= 0.137 mmÀ1. Triclinic, P1 (no. 2),
¯
Rint = 0.0279; F(000) = 472;
a = 962.2(2), b = 1113.9(2),
= 76.32(1),
= 82.70(1)8, V = 1076.8(3) 106 pm3, Z = 4; R values:
m
c = 1145.8(2) pm,
a = 64.54(1),
1
5
b
g
(376.4 MHz, CDCl3):
d
À76.3 (dd, JF,C = 283 Hz, JF,F = 13.6 Hz,
1 5
R1/wR2 for 3614 reflections with [I0 > 2
data: 0.0832/0.1614; Sall = 1.038.
s(I0)]: 0.0500/0.1358, for all
3JF,F = 10.9 Hz, CF3), À143.4 (qdd, JF,C = 245 Hz, JF,F = 13.6 Hz,
4JF,F = 6.6 Hz, JF,H = 4.5 Hz, FC = C), À177.6 (qd, JF,C = 242 Hz,
4
1
3JF,F = 10.9 Hz, JF,F = 6.6 Hz, CF(CF3)). MS (EI): m/z (%) = 342 (10)
4
4.12. N-tert-Butyl-2,3,3,3-tetrafluoropropionamide (5c)
[M]+, 286 (40) [MÀC4H8]+, 230 (100) [MÀ2C4H8]+. Anal. Calcd for
C
14F5H19N2O2 (342.31): C 49.12, F 27.75, H 5.59, N 8.18. Found: C
Yield 0.61 g (61%), white solid, mp 55 8C. 1H NMR (300.13 MHz,
49.01, F 27.70, H 5.52, N 8.13.
2
3
CDCl3):
1H, CHF), 6.13 (broad s, 1H, NH). 13C (75.47 MHz, CDCl3):
CH3), 52.4 (C), 85.6 (CFH), 122.1 (CF3), 160.0 (CO). 19F (282.4 MHz,
d
1.43 (s, 9H, CH3), 4.95 (dq, JH,F = 46.9 Hz, JH,F = 6.6 Hz,
Crystal data of 7: C14H19F5N2O2, 342.31 g molÀ1. Diffractometer
d
28.5 (3C,
IPDS-I, Stoe Darmstadt; Mo–Ka
(graphite monochromator,
a
À
l
= 71.073 pm); T = 293(2) K;
Dw = 28, 100 images; À15 ꢁ h ꢁ 15, À12 ꢁ k ꢁ 13, À18 ꢁ l ꢁ 18;
calc = 1.348 g cmÀ3; 14,258 measured reflections of which 3775
were symmetrically independent; Rint = 0.0613; F(000) = 712;
= 0.127 mmÀ1
Monoclinic, P21/c (no. 14), a = 1179.6(3),
b = 1079.3(2), c = 1377.2(4) pm, = 105.91(2)8, V = 1686.4(7)
106 pm3, Z = 4;
values: R1/wR2 for 1732 reflections with
[I0 > 2 (I0)]: 0.0623/0.1542, for all data: 0.1343/0.1842;
2
umax = 56.38; 08 ꢁ
w
ꢁ 2008,
1
3
3
CDCl3):
d
À76.1 (dd, JF,C = 282 Hz, JF,F = 10.9 Hz, JF,H = 6.6 Hz,
1 2 3
CF3), À199.0 (dqd, JF,C = 204 Hz, JF,H = 46.9 Hz, JF,F = 10.9 Hz,
4JF,H = 3.7 Hz, CFH). MS (EI): m/z (%) = 201 (10) [M]+, 186 (100)
[MÀCH3]+. Anal. Calcd for C7F4H11NO (201.17): C 41.79, F 37.78, H
5.51, N 6.96. Found: C 41.73, F 37.70, H 5.48, N 6.92.
Method B: To a solution of 2,3,3-trifluoroacrylamide 2 (5 mmol)
in dimethoxyethane (DME) (15 mL) at À35 8C [Me4N]F (0.47 g,
5 mmol) was added. The mixture was stirred for 1 h at À35 Æ 5 8C
and then allowed to reach room temperature. All volatile components
were removed in vacuo and the product was extracted into hexane.
Insoluble impurities were filtered off and the solvent was evaporated
in vacuo. The amides 5a and 5b were purified by crystallization from
pentane to yield 0.91 g (65%) and 0.76 g (67%), correspondingly. The
amide 5c and cyclic products 6 and 7 were separated by silica gel
column chromatography.
r
m
.
b
R
s
Sall = 0.975.
4.15. General procedure for the synthesis of 2,3,3,3-
tetrafluorothiopropionamides 9
To a mixture of isothiocyanate 3 (5 mmol) and [Me4N]F (0.51 g,
5.5 mmol) in dimethoxyethane (DME) (30 mL) at À60 8C,
Et3SiCF = CF2 (1.23 g, 6.25 mmol) was added dropwise over a
period of 30 min. The mixture was stirred for 90 min at À55 Æ 5 8C
and then HBF4ÁEt2O (0.81 g, 5 mmol) was added. The reaction mixture
was stirred for 30 min at À35 Æ 5 8C and [Me4N]F (0.47 g, 5 mmol)
was added. The resulting mixture was stirred for 1 h at À35 Æ 5 8C
and then allowed to reach room temperature. All volatile components
were removed in vacuo and the product was extracted into hexane.
The precipitated [Me4N][BF4] was filtered and the solvent was
evaporated in vacuo. The thioamides 9 were purified by silica gel
column chromatography.
N-tert-Butyl-2,3,3,3-tetrafluoropropionamide (5c): Yield 0.36 g
(36%).
4.13. N-tert-butyl-2-[1-tert-butyl-3-fluoro-4-oxo-3-
trifluoromethyl-azetidin-(2Z)-ylidene]-2-fluoro-acetamide (6)
Yield 0.38 g (22%), white solid, mp 141–142 8C, Rf 0.2 (hexane/
diethyl ether 4:1). 1H NMR (400.13 MHz, CDCl3):
d
1.43 (s, 9H, CH3
6
(t-Bu) amide), 1.54 (d, JH,F = 0.9 Hz, 9H, CH3 (t-Bu) lactam), 5.95
(broad s, D1/2 ꢀ 12 Hz, 1H, NH). 13C (100.61 MHz, CDCl3):
d 28.6
(3C, CH3 (t-Bu) amide), 28.7 (d, 5JF,C = 7 Hz, 3C, CH3 (t-Bu) lactam),
51.8 (C (t-Bu) amide), 58.4 (C (t-Bu) lactam), 97.8 (CF(CF3)), 120.1
(CF3), 124.3 (FC = C lactam), 133.9 (FC = C lactam), 157.0 (CO
4.16. N-Cyclohexyl-2,3,3,3-tetrafluorothiopropionamide (9a)
Yield 0.63 g (52%), liquid, bp 64–65 8C/0.04 Torr, Rf 0.4 (hexane/
amide), 158.4 (CO lactam). 19F (376.4 MHz, CDCl3):
d
À74.2 (d,
diethyl ether 19:1). 1H NMR (300.13 MHz, CDCl3):
d 1.36 (m, 5H, c-
3
1JF,C = 284 Hz, JF,F = 10.0 Hz, CF3), À139.0 (broad s, D1/2 ꢀ 7 Hz,
C6H11), 1.73 (m, 3H, c-C6H11), 2.08 (m, 2H, c-C6H11), 4.41 (m, 1H, c-
C6H11), 5.46 (dq, 2JH,F = 46.9 Hz, 3JH,F = 5.5 Hz, 1H, CHF), 7.72 (broad
1JF,C = 267 Hz, FC = C), À173.9 (qd, JF,C = 247 Hz, JF,F = 10.0 Hz,
4JF,F ꢀ 1 Hz, CF(CF3)). MS(EI): m/z (%) = 342 (15) [M]+, 286 (55)
[MÀC4H8]+, 230 (100) [MÀ2C4H8]+. Anal. Calcd for C14F5H19N2O2
(342.31): C 49.12, F 27.75, H 5.59, N 8.18. Found: C 49.03, F 27.69, H
5.54, N 8.14.
1
3
s, 1H, NH). 13C (100.47 MHz, CDCl3):
d
24.4 (d, 6JC,F = 4 Hz, 2C, CH2),
5
25.3 (CH2), 31.0 (d, JC,F = 7 Hz, 2C, CH2), 51.6 (CH), 90.9 (dq,
1JC,F = 209 Hz, 2JC,F = 32 Hz, CFH), 120.5 (qd, 1JC,F = 283 Hz,
2
2JC,F = 27 Hz, CF3), 184.9 (d, JC,F = 14 Hz, CS). 19F (282.4 MHz,
Crystal data of 6: C14H19F5N2O2, 342.31 g molÀ1. Diffractometer
IPDS-I, Stoe Darmstadt; Mo–Ka
CDCl3):
d
À75.8 (dd, JF,C = 283 Hz, JF,F = 10.9 Hz, JF,H = 5.5 Hz,
1
3
3
1 2 3
(graphite monochromator,
CF3), À187.9 (dqdd, JF,C = 209 Hz, JF,H = 46.9 Hz, JF,F = 10.9 Hz,
4JF,H = 5.6 Hz, 6JF,H = 1.6 Hz, CFH). MS (EI): m/z (%) = 243 (100) [M]+.
Anal. Calcd for C9F4H13NS (243.28): C 44.43, F 31.24, H 5.39, N 5.76.
Found: C 44.33, F 31.15, H 5.32, N 5.70.
À
2
a
l
= 71.073 pm); T = 293(2) K;
Dw = 28, 100 images; À14 ꢁ h ꢁ 14, À23 ꢁ k ꢁ 23, À11 ꢁ l ꢁ 10;
calc = 1.290 g cmÀ3; 12,401 measured reflections of which 3739
u
max = 56.38; 08 ꢁ
w
ꢁ 2008,
r

30
N.V. Kirij et al. / Journal of Fluorine Chemistry 147 (2013) 22–30
(c) I.L. Knunyants, R.N. Sterlin, R.D. Yatsenko, L.N. Pinkina, Russ. Chem. Bull. 7
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4.17. N-Ethyl-2,3,3,3-tetrafluorothiopropionamide (9b)
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Yield 0.47 g (49%), liquid, bp 58 8C/10 Torr, Rf 0.15 (hexane/
diethyl ether 19:1). 1H NMR (400.13 MHz, CDCl3):
d 1.33 (t,
3
3
3JH,H = 7.2 Hz, 3H, CH3), 3.76 (qd, JH,H = 7.2 Hz, JH,H = 5.2 Hz, 2H,
CH2), 5.49 (dq, 2JH,F = 46.8 Hz, 3JH,F = 5.6 Hz, 1H, CHF), 7.86 (broad s,
1H, NH). 13C (100.6 MHz, CDCl3):
d 12.9 (CH3), 34.5 (CH2), 91.2 (dq,
1JC,F = 209 Hz, 2JC,F = 32 Hz, CFH), 120.6 (qd, 1JC,F = 283 Hz,
2JC,F = 27 Hz, CF3), 186.5 (d, JC,F = 14 Hz, CS). 19F (282.4 MHz,
2
CDCl3):
d
À76.9 (dd, 1JF,C = 283 Hz, 3JF,F = 11 Hz, 3JF,H = 5.6 Hz, CF3),
À189.5 (dqdd, 1JF,C = 209 Hz, 2JF,H = 46.8 Hz, 3JF,F = 11 Hz,
4JF,H = 4.4 Hz, CFH). MS (EI): m/z (%) = 189 (100) [M]+. Anal. Calcd
for C5F4H7NS (189.19): C 31.74, F 40.17, H 3.73, N 7.40. Found: C
31.65, F 40.09, H 3.68, N 7.35.
4.18. N-Phenyl-2,3,3,3-tetrafluorothiopropionamide (9c)
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56 (1991) 5263–5277.
Yield 0.70 g (59%), yellow solid, mp 58 8C, Rf 0.25 (hexane/
diethyl ether 9:1). 1H NMR (300.13 MHz, CDCl3):
d
5.63 (dq,
3
3
2JH,F = 46.9 Hz, JH,F = 5.6 Hz, 1H, CHF), 7.36 (t, JH,H = 7.6 Hz, 1H,
3
3
C6H5), 7.46 (t, JH,H = 7.6 Hz, 2H, C6H5), 7.77 (d, JH,H = 7.6 Hz, 2H,
C6H5), 9.28 (broad s, 1H, NH). 13C (100.6 MHz, CDCl3):
d 91.9 (dq,
1JC,F = 211 Hz, 2JC,F = 32 Hz, CFH), 120.6 (qd, 1JC,F = 283 Hz,
2JC,F = 27 Hz, CF3), 123.6 (2C, C6H5), 128.1 (C, C6H5), 129.5 (2C,
C6H5), 137.0 (C, C6H5), 184.4 (d, JC,F = 14 Hz, CS) 19F (282.4 MHz,
2
1
3
3
CDCl3):
d
À75.6 (dd, JF,C = 283 Hz, JF,F = 11.2 Hz, JF,H = 5.6 Hz,
1 2 3
CF3), À184.9 (dqd, JF,C = 211 Hz, JF,H = 46.9 Hz, JF,F = 11.2 Hz,
4JF,H = 7.0 Hz, CFH). MS (EI): m/z (%) = 237 (100) [M]+. Anal. Calcd
for C9F4H7NS (237.23): C 45.57, F 32.04, H 2.97, N 5.90. Found: C
45.49, F 31.97, H 2.93, N 5.84.
Acknowledgements
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(1993) 343.
The generous financial support of this work by the DFG (grant
436 UKR 113) is gratefully acknowledged. We are indebted to Dr.
Alexander B. Rozhenko (Kiev) for recording a great number of the
13C NMR spectra and Dr. Hendrik T. M. Fischer (Ko¨ln) for selecting
and mounting single crystals of compounds 6 and 7.
References
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