1,1,3,3,3-Pentafluoropropene secondary amine adducts new selective fluorinating agents

Article abstract of DOI:10.1016/j.jfluchem.2006.07.006

Addition of secondary amine SA (dimethylamine DMA, diethylamine DEA, pyrrolidine Pyr, piperidine Pip, morpholine Mor) to pentafluoropropene PFP gives rise to generation of mixtures of two products (1-dialkylamine-1,3,3,3-tetrafluoropropene and N,N-dialkyl-1,1,3,3,3-pentafluoropropylamine) in different ratios. Those reaction mixtures, however, were found to be efficient fluorinating agents replacing hydroxyl groups in alcohols into fluorine. In general, they react with alcohols yielding corresponding fluorides, equimolar amounts of appropriate 3,3,3-trifluoropropionamide and hydrogen fluoride. Aliphatic primary alcohols including octanol and benzylic alcohol yield only alkyl fluorides. The secondary and tertiary alcohols, beside the desired fluorides, give usually considerably amount of alkenes.

Full text of DOI:10.1016/j.jfluchem.2006.07.006

Journal of Fluorine Chemistry 127 (2006) 1245–1251
www.elsevier.com/locate/fluor
1,1,3,3,3-Pentafluoropropene secondary amine adducts
new selective fluorinating agents
a
Henryk Koroniak a, , Justyna Walkowiak ,
*
Krzysztof Grys a, Andrzej Rajchel a, Adam Alty b,
Rick Du Boisson b
a
´
Adam Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan, Poland
b SynQuest Laboratories Inc., PO Box 309, Alachua, FL 32616-0309, USA
Received 1 April 2006; received in revised form 5 July 2006; accepted 7 July 2006
Available online 14 July 2006
Abstract
Addition of secondary amine SA (dimethylamine DMA, diethylamine DEA, pyrrolidine Pyr, piperidine Pip, morpholine Mor) to penta-
fluoropropene PFP gives rise to generation of mixtures of two products (1-dialkylamine-1,3,3,3-tetrafluoropropene and N,N-dialkyl-1,1,3,3,3-
pentafluoropropylamine) in different ratios. Those reaction mixtures, however, were found to be efficient fluorinating agents replacing hydroxyl
groups in alcohols into fluorine. In general, they react with alcohols yielding corresponding fluorides, equimolar amounts of appropriate 3,3,3-
trifluoropropionamide and hydrogen fluoride. Aliphatic primary alcohols including octanol and benzylic alcohol yield only alkyl fluorides. The
secondary and tertiary alcohols, beside the desired fluorides, give usually considerably amount of alkenes.
# 2006 Elsevier B.V. All rights reserved.
Keywords: Fluorination; Nucleophilic fluorination; Pentafluoropropene-amine adduct; Ishikawa reagent
1. Introduction
This paper presents the researches dealing with the reactivity
of 1,1,3,3,3-pentafluoropropene PFP secondary amines SA
adducts, their selectivity and utility in organic synthesis as new
fluorinating agents.
The replacement of a hydroxyl group with fluorine is a
useful technique for the introduction of fluorine into organic
compounds. Fluorinating agents such as hydrogen fluoride-
pyridine (Olah’s reagent) [1–3], sulfur tetrafluoride [1,4,5],
dialkylaminotrifluorosulfuranes (e.g. DAST, [1,6]) and a-
fluoroamines [1] are widely employed in organic synthesis for
the conversion of alcohols and carbonyl compounds into
corresponding fluorides. Fluoroamino reagents such as N,N-
diethyl-1,1,2,3,3,3-hexafluoropropylamine, in literature known
as 1,1,2,3,3,3-hexafluoropropyl-N,N-diethylamine (Ishikawa
reagent [7]) and N,N-dimethyl-1,1,2,2-tetrafluoroethylamine
(Petrov reagent 1,1,2,2-tetrafluoroethyl-N,N-dimethylamine)
[8], (both prepared by the addition of a dialkylamine to the
corresponding fluoro-olefin) have been found to be effective
reagents for the conversion of alcohols into alkyl fluorides [9].
2. Results
2.1. Preparation of 1,1,3,3,3-pentafluoropropene
secondary amine adducts
Synthesis of the title compounds is based on the nucleophilic
addition of secondary amine across the double bond of
1,1,3,3,3-pentafluoropropene (PFP), and was carried out using
a literature procedures [7,10]. Two methods were applied to the
synthesis of those adducts, firstly in an autoclave at high
pressure (Reaction 1, ꢀ78 to 25 8C, diethyl ether, autoclave)
and secondly at atmospheric pressure (Reaction 2, 0–5 8C,
diethyl ether, atmospheric pressure). In each case, these
reactions gave a mixture of two products a-fluoroenamine 1a–e
and the desired a-fluoroamine 2a–e in different molar ratios
(Table 1). No difference was observed in yields of reactions
related to the way of preparation of fluorinating agent
* Corresponding author.
E-mail address: koroniak@amu.edu.pl (H. Koroniak).
0022-1139/$ – see front matter # 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2006.07.006

1246
H. Koroniak et al. / Journal of Fluorine Chemistry 127 (2006) 1245–1251
secondary hydroxyl group—5-cholestene-3b-ol and (R)-(ꢀ)-2-
octanol; (3) alcohols with tertiary hydroxyl group—tert-butanol.
Substantially, each new fluorinating agent reacts with
alcohols yielding corresponding fluorides, equimolar amounts
of appropriate 3,3,3-trifluoropropionamide and hydrogen
fluoride (Reaction 4). In some cases, however, considerable
amounts of by-products were formed, which causes lower
yields of the fluorides, being major expected products.
Our findings differ from those obtained by Ishikawa,
considering the results of dialkylamines (DMA, DEA) penta-
fluoropropene adducts preparation. In Ishikawa’s reactions (the
addition of DEA to HFP) the main fluorinated product was N,N-
diethyl-1,1,2,3,3,3-hexafluoropropylamine (DEHFPA), while in
our case 1-dialkylamino-1,3,3,3-tetrafluoropropenes (DAATFP)
1a–b were formed exclusively or as the main product and the
expectedfluorinatingagentswere, foundonlyintraceamounts. It
seems that the primary adducts (like 2) of 1,1,3,3,3-pentafluoro-
propene and dialkylamines are loosing HF during thermal
work-up. Striking difference can be observed in case of PFP
adducts with cyclic amines, where the desired a-fluoroamines
2c–e were obtained as the major products.
At first glance, 1-dialkylamino-1,3,3,3-tetrafluoropropene,
the major product of addition of PFP to dimethylamine (DMA)
or diethylamine (DEA), should not react with alcohols.
Surprisingly however, using this reagent in the reaction with
alcohols, it still appears to be an effective fluorinating agent,
quite comparable to the Ishikawa reagent. It is assumed that our
fluorinating mixtures are the equilibrium between a-fluoro-
enamine 1a–e and a-fluoroamine 2a–e, where only the HF
elimination/addition reaction determines the ratio of products.
This also suggests that the presence of even traces of HF will
trigger the fluorination. All presented fluorinating mixture are
readily hydrolyzed on being exposed to moist air; they react
vigorously with water, forming the N,N-diethyl-3,3,3-trifluoro-
propionamide and hydrogen fluoride (Reaction 3)
The general procedure for each reaction was as follows: in
case of dialkylamines adducts (DMA, DEA), alcohols were
mixed with adducts in molar ratio 1:1.2 (alcohol:fluorinating
agent), while for the reactions of cyclic adducts (pyrrolidine,
morpholine, piperidine), alcohols were added drop wise
directly into a crude fluorinating mixtures (alcohol:cyclic
amine, molar ratio was 1:3). Yields were determined by 19F
NMR. Two internal references were used: a,a,a-trifluoro-
toluene 19F NMR (CDCl3, CFCl3) d ꢀ63.2 (s, 3F, CF3) and m-
fluorotoluene 19F NMR (CDCl3, CFCl3) d ꢀ114.1 (m, 1F, CF).
Each reaction was carried out at least three times and the
average results are presented in Table 2.
In general the yields of reactions with new fluorinating
agents were slightly lower in comparison with Ishikawa’s
reagent [7,8]. Therefore, it was decided to optimize the effect of
stoichiometry on the fluorination of alcohols with (2H)-
pentafluoropropene secondary amine adducts. Studies on
optimization of fluorination reaction were divided into two
parts. First one concerned the fluorination reactions with
pentafluoropropene diethylamine adduct (DEPFPA). In this
case, the least reactive alcohols: 5-cholesten-3b-ol, tert-butanol
and (R)-(ꢀ)-2-octanol were chosen to check the reactivity. The
experimental results are presented in Table 3.
The aim of the second part of stoichiometry investigations
was to compare the reactivity of pentafluoropropene cyclic
amines adducts (PyrPFP, PipPFP, MorPFP) in fluorination
reaction of benzyl alcohol (Reaction 5)
Although the fluorinating mixtures are stable thermally, in
most of the experiments they were either distilled (DME, DEA
adducts) or freshly prepared (Pyr, Pip, Mor adducts) before
use.
2.2. Reactions of PFP secondary amines adducts with
alcohols
The experimental results are presented in Table 4.
Comparing our results with literature data, 1,1,3,3,3-
pentafluoropropene secondary adducts are found to be selective
agents for the conversion of alcohols into corresponding
fluorides, however, they are slightly less reactive than
Ishikawa’s reagent.
The new fluorinating mixtures were tested on several
compounds: (1) alcohols with primary hydroxyl group—benzyl
alcohol, 2-phenylethanol and 1-octanol; (2) alcohols with

H. Koroniak et al. / Journal of Fluorine Chemistry 127 (2006) 1245–1251
1247
Table 1
Molar ratio of products in the new fluorinating mixtures
R2NH
Products mixture
1a (12):2a (1)
1b (main):2b (traces)
Scheme 1.
1c (1):2c (5)
1d (traces):2d (main)
2.3. Mechanistic considerations
1e (1):2e (8)
It is known that the key step in the fluorinating reaction is the
nucleophilic attack of fluoride on the carbon atom bearing the
hydroxyl group. But there are doubts if the process goes
through a monomolecular mechanism for nucleophilic sub-
stitution (SN1) or a bimolecular mechanism for nucleophilic
substitution (SN2 or SNi). The first mechanism for the
fluorination of alcohols was suggested by Ishikawa et al. [7].
It shows all possible ways for the transformation of the
intermediate. A different approach was suggested by Petrov
et al. [8]. He assumed that this reaction goes through two-step
process:
In the reaction of PFP and secondary amine adducts
(Ishikawa-type fluorinating agent) with hydroxyl containing
compounds, apart from the expected products RF and
appropriate 3,3,3-trifluoropropionamide, hydrogen fluoride
(HF) is also produced. HF immediately adds to a-fluoroena-
mine (e.g. 1-dialkylamino-1,3,3,3-tetrafluoropropene) leading
to the formation in situ of a-fluoroamine (e.g. N,N-dialkyl-
1,1,3,3,3-pentafluoropropylamine) which then reacts with
alcohols (Scheme 1). Undoubtedly due to this, the mixtures
of: N,N-dialkyl-1,1,3,3,3-pentafluoropropylamine and 1-dia-
lkylamino-1,3,3,3-tetrafluoropropene could be regarded as a
good fluorinating agents.
(1) Formation of an intermediate as a result of the reaction
between the alcohol and 1,1,3,3,3-pentafluoropropyl-N,N-
dialkylamine or -N-cycloamine.
(2) Decomposition of this intermediate with the formation of
products (Scheme 2).
Table 2
Yield (%) of fluorination reaction of alcohols
Alcohols
25 8C
60 8C
25 8C
25 8C
60 8C
25 8C
60 8C
25 8C
60 8C
CH3(CH2)7OH (4)
PhCH2OH (5)
PhCH2CH2OH (6)
CH3CH(OH)(CH2)2CH3 (7)
5-Cholesten-3(-ol (8)
Cyclohexanol (9)
50
95
–
92
96
–
74
64
–
9
95
23
28
50
5
10
95
26
29
98
12
4
18
88
30
69
77
7
89
82
89
–
39
88
10
64
68
6
80
97
64
56
88
15
37
–
–
–
42
10
12
70
–
33
–
89
7
tert-Butanol (10)
20
38
37
48
2
80
Yields were determined by 19F NMR.
Table 3
Optimization of the fluorination reaction with DEPFPA
Molar ratio
Product yields (%)
ROH:DEPFPA
(R)-(ꢀ)-2-Octanol (11)
5-Cholesten-3b-ol (8)
tert-Butanol (10)
1:1
54
–
33
–
38
72
84
71
1:1.5
1:2
75
85
79
93
1:3
Yields were determined by 19F NMR.

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H. Koroniak et al. / Journal of Fluorine Chemistry 127 (2006) 1245–1251
Table 4
Optimization of the fluorination reaction with 1,1,3,3,3-pentafluoropropene cyclic amine adducts
Molar ratio
ROH:amine
1,1,3,3,3-Pentafluoropropene amine adducts (%)
25 8C
60 8C
25 8C
65 8C
25 8C
65 8C
1:1
11
56
72
–
–
58
–
48
–
46
–
–
–
–
–
1:2
1:2.5
1:3
99
88
–
77
82
–
–
–
–
88
–
97
–
1:5
95
72
Yields were determined by 19F NMR.
Scheme 2.
The absence of any noticeable amount of elimination
products in the reaction of primary alcohol and PFPSA,
indicates that transformation does not involve the formation of
a free carbonium cation, and may proceed through a cyclic
transition state (Scheme 3).
Scheme 3.
made carrying out NMR analysis difficult, because concentra-
tion of 1,1,1,2-tetrafluoroethane was too low. Although we were
not able to carry out this experiment quantitatively, 19F NMR
and 1H NMR spectra gave unquestionable proof that expected
product arose.
The striking difference in the reactivity of primary and
secondary and/or tertiary alcohols in reaction with N,N-dialkyl-
or N-cyclo-1,1,3,3,3-pentafluoropropylamine and other
reagents from a-fluoroamine group, most logically, could be
due to the steric effect. Also bearing in mind that the reaction of
primary alcohols proceeds without noticeable formation of
elimination products, this is in good agreement with the
proposed mechanism by Petrov. Reaction of 2,2,2-trifluor-
oethanol with N,N-diethyl-1,1,3,3,3-pentafluoropropyl-amine
(DEPFPA) showed interesting results. Boiling point of
expected product, 1,1,1,2-tetrafluoroethane 12 (bp ꢀ26.1 8C)
The mechanism proposed above is based on analogy to
previously described mechanisms by Petrov, assuming that the
fluorinating agent is formed in situ as an adduct of compounds
1a–e and HF. However, one can envision compounds 1a–e as
fluorinating agents itself undergoing fluorination via process
shown on Scheme 4. So far we do not have any supporting
proofs on this mechanism.
Scheme 4.

H. Koroniak et al. / Journal of Fluorine Chemistry 127 (2006) 1245–1251
1249
3. Conclusions
ing residue was subjected to distillation in a vacuum, and a
colourless liquid (6.3 g, 41%, bp 69–75 8C/72 mmHg), was
obtained. The 19F NMR spectrum revealed that this oil is a
mixture of 1-dimethylamino-1,3,3,3-tetrafluoropropene and
N,N-dimethyl-1,1,3,3,3-pentafluoropropylamine (traces).
It was demonstrated that the reactions of (2H)-pentafluor-
opropene with dimethylamine, diethylamine, pyrrolidine,
piperidine, morpholine proceed under mild conditions produ-
cing the fluorinating mixtures of 1-dialkylamino- or 1-
cycloamino-1,3,3,3-tetrafluoropropene and N,N-dialkyl- or N-
cyclo-1,1,3,3,3-pentafluoropropylamine (the latter being the
actual fluorinating agent). DAPFPAs are found to be effective
and selective fluorinating agents for the conversion of alcohols
into the corresponding fluorides. The mechanism of this
transformation proceeds according to a nucleophilic substitu-
tion scheme. Experimental data obtained in this work proved
that atleast in the reaction of (R)-(ꢀ)-2-octanol with N,N-
diethyl-1,1,3,3,3-pentafluoropropylamine the complete con-
version of configuration in the product was observed; i.e. the
only pure product was (S)-(+)-2-fluorooctane 11. This finding
strongly supports the suggested SNi mechanism of this
fluorination reaction.
3
19F NMR (CDCl3, CFCl3): d ꢀ52.5 (dd, 3F, JHF = 6.9 Hz,
3
4
4JFF = 15.3 Hz, CF3), ꢀ61.9 (tt, 3F, JHF = 9.9 Hz, JFF
=
3
4
20.6 Hz, CF3), ꢀ85.9 (tq, 2F, JHF = 11.4 Hz, JFF = 20.6 Hz,
3
4
CF2), ꢀ91.5 (dq, 1F, JHF = 31.0 Hz, JFF = 15.3 Hz, CFN
(CH3)2).
4.1.2. Diethylamine 1,1,3,3,3-pentafluoropropene adduct
(1b and 2b)
According to the general procedure the mixture of 1b and 2b
was prepared from diethylamine (10.5 g, 140 mmol) and
1,1,3,3,3-pentafluoropropene (21 g, 160 mmol). The resulting
residue was subjected to distillation in a vacuum, and a
yellowish liquid (18.2 g, 56%, bp 95 8C/72 mmHg), was
obtained. The 19F NMR spectrum revealed that this oil is a
mixture of 1-diethylamino-1,3,3,3-tetrafluoropropene and N,N-
diethyl-1,1,3,3,3-pentafluoropropylamine (traces).
4. Experimental
3
19F NMR (CDCl3, CFCl3): d ꢀ51.8 (dd, 3F, JFH = 7 Hz,
4.1. General procedure for the synthesis of (2H)-
pentafluoropropene secondary amine adducts
4JFF = 15 Hz, CF3), ꢀ93.3 (dq, 1F, 3JFH = 34 Hz, 4JFF = 15 Hz,
CFN(C2H5)2).
Reaction under pressure [7]: Secondary amine (1 equiv.)
and dried diethylether (5–30 mL) were placed in a Carius tube,
and the whole was cooled to ꢀ78 8C by means of a dry ice/
acetone bath. The excess of (2H)-pentafluoropropene was
transferred to the tube from balloon via a needle (over 3 h). The
mixture was stirred overnight while warming up to room
temperature. After removing of the solvent the residues of
dialkylamines (DMA, DEA) pentafluoropropene adducts can
be purified by distillation in a vacuum. Adducts of cyclic
amines (pyrrolidine, morpholine, piperidine) were impossible
to distil under reduced pressure so the crude products were used
for the next step.
4.1.3. Pyrrolidine 1,1,3,3,3-pentafluoropropene adduct (1c
and 2c)
According to the general procedure the mixture of 1c and 2c
was prepared from pyrrolidine (0.22 g, 3 mmol) and 1,1,3,3,3-
pentafluoropropene (0.92 g, 7 mmol). It was not possible to
distil the resulting residue. Therefore, the 19F NMR analysis
was performed from the crude mixture.
19F NMR 1c (CDCl3, CFCl3): d ꢀ50.6 (dd, 3F, JHF
6.8 Hz, 4JFF = 15.1 Hz), ꢀ86.8 (dq, 1F, 3JHF = 34.0 Hz, 4JFF
15.1 Hz).
=
=
3
4.1.4. Morpholine 1,1,3,3,3-pentafluoropropene adduct (1d
and 2d)
According to the general procedure the mixture of 1d and 2d
was prepared from morpholine (10.5 g, 140 mmol) and
1,1,3,3,3-pentafluoropropene (21 g, 160 mmol). The 19F
Reaction at atmospheric pressure [7]: A solution of
secondary amine (1 equiv.) in dried diethylether (30 mL)
was placed in a two-necked flask which was equipped with a
dry ice/acetone/cooled reflux condenser and a gas inlet tube.
The whole was cooled to 0–5 8C with an ice-bath and the excess
of (2H)-pentafluoropropene was transferred into the reflux
condenser (over 3 h). The cooling bath was removed and the
mixture was brought to room temperature with overnight
stirring. After removing of the solvent the residues of
dialkylamines (DMA, DEA) pentafluoropropene adducts can
be purified by distillation in a vacuum. Adducts of cyclic
amines (pyrrolidine, morpholine, piperidine) were impossible
to distil under reduced pressure so the crude products were used
for the next step.
NMR analysis was performed from the crude mixture.
3
19F NMR (CDCl3, CF3COOD): d ꢀ52.5 (dd, 3F, JHF
=
4
3
7.0 Hz, JFF = 15.2 Hz, CF3), ꢀ61.9 (tt, 3F, JHF = 9.6 Hz,
4JFF = 19.1 Hz, CF3), ꢀ83.7 (tq, 2F, JHF = 11.0 Hz, JFF
=
3
4
20.0 Hz, CF2), ꢀ91.9 (dq, 1F, 3JHF = 31.6 Hz, 4JFF = 15.2 Hz,
CF(NC4H8O)).
4.1.5. Piperidine 1,1,3,3,3-pentafluoropropene adduct (1e
and 2e)
According to the general procedure the mixture of 1e and 2e
was prepared from diethylamine (10.5 g, 140 mmol) and
1,1,3,3,3-pentafluoropropene (21 g, 160 mmol). The resulting
4.1.1. Dimethylamine 1,1,3,3,3-pentafluoropropene adduct
(1a and 2a)
According to the general procedure the mixture of 1a and 2a
was prepared from dimethylamine (4.4 g, 97 mmol) and
1,1,3,3,3-pentafluoropropene (13.9 g, 104 mmol). The result-
residue was analyzed by the 19F NMR.
3
19F NMR 1e (CDCl3, CF3COOD): d ꢀ51.8 (dd, 3F, JHF
=
=
4
3
7.4 Hz, JFF = 14.9 Hz), ꢀ81.4 (s, 2F), ꢀ90.6 (dq, 1F, JHF
4
31.0 Hz, JFF = 14.9 Hz).

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H. Koroniak et al. / Journal of Fluorine Chemistry 127 (2006) 1245–1251
4.2. General procedure for the reactions of the new
fluorinating mixtures with alcohols
4.2.5. Cholesteryl fluoride (8)
According to the general procedure 8 was prepared from 5-
cholesten-3b-ol (0.58 g, 1.5 mmol) and crude fluorinating
mixture 1d + 2d (0.4 g, 4.4 mmol of morpholine, 1.1 g,
8.1 mmol of pentafluoropropene) in diethylether (7 mL) at room
temperature. After stirring for 18 h, the appropriate amount of
NMR internal standard was added (m-fluorotoluene) a sample
analyzed by NMR.
A solution of an alcohol was added drop wise into a solution
of the fluorinating mixture. After stirring for 4–20 h, the
appropriate amount of NMR internal standard was added (m-
fluorotoluene). The yields were determined by 19F NMR. In
case of dialkylamines adducts (DMA, DEA) alcohols were
mixed with adducts in molar ratio 1:1.2 (alcohol:fluorinating
agent), while for the reactions of cyclic adducts (pyrrolidine,
morpholine, piperidine) alcohols were added drop wise directly
into a crude fluorinating mixtures (alcohol:cyclic amine molar
ratio was 1:3).
19F NMR (CDCl3, CFCl3): d ꢀ167.7 (dm, 1F, 2JFH = 50 Hz,
J
FH = 7 Hz, CHF) [14].
Then reaction mixture was added to water. An oily layer was
extracted with dichloromethane, and the extract was washed
with water, dried over magnesium sulfate and subjected to
column chromatography on silica gel. Petroleum ether was
used as an eluent and the main elution was subjected to
evaporate, affording white crystals of cholesteryl fluoride mp
4.2.1. 1-Fluorooctane (4)
According to the general procedure 4 was prepared from 1-
octanol (0.65 g, 5 mmol) and the fluorinating mixture 1b + 2b
(1.3 g, 6 mmol) in diethylether (5 mL) at 0–5 8C. After stirring
for 4 h, the appropriate amount of NMR internal standard was
added (m-fluorotoluene) and a sample analyzed by NMR.
25
98–99 8C [11], optical rotation ½aꢁD ꢀ 53:3ꢂ (c 1, CHCl3) [11].
4.2.6. (S)-(+)-2-Fluorooctane (11)
According to the general procedure 11 was prepared from
(R)-(ꢀ)-2-octanol (0.65 g, 5 mmol) and the fluorinating
mixture 1b + 2b (1.3 g, 6 mmol) in diethylether (5 mL) at 0–
5 8C. After stirring for 4 h, the appropriate amount of NMR
internal standard was added (m-fluorotoluene) and a sample
analyzed by NMR.
19F NMR (CDCl3, CFCl3): d ꢀ174.5 (m, 1F, CHF) [11,17].
Then reaction mixture was added to water. An oily layer was
extracted with diethylether, and the extract was washed with
water, dried over magnesium sulfate and evaporated to remove
the solvent. The residue was distilled in a vacuum. Bp 73–
2
19F NMR (CDCl3, CFCl3): d ꢀ218.3 (tt, 1F, JFH = 48 Hz,
3JFH = 25 Hz, CH2F) [11,12].
4.2.2. Benzyl fluoride (5)
According to the general procedure 5 was prepared from
benzyl alcohol (0.56 g, 5 mmol) and the fluorinating mixture
1a + 2a (1.2 g, 6 mmol) in chloroform (5 mL) at room
temperature. After stirring for 17 h, the appropriate amount
of NMR internal standard was added (m-fluorotoluene) a
sample analyzed by NMR.
25
2
19F NMR (CDCl3, CFCl3): d ꢀ206.9 (t, 1F, JFH = 48 Hz,
75 8C/83 mmHg [11,17], optical rotation point ½aꢁD þ 11:36ꢂ
CH2F) [13].
(c 1, CHCl3) [11].
4.2.3. 2-Phenylfluoroethane (6)
4.2.7. Fluorocyclohexane (9)
According to the general procedure 6 was prepared from 2-
phynyloethanol (0.61 g, 5 mmol) and crude fluorinating
mixture 1c + 2c (1.1 g, 15 mmol of pyrrolidine, 2.9 g, 16 mmol
of pentafluoropropene) in diethylether (5 mL) at room
temperature. After stirring for 18 h, the appropriate amount
of NMR internal standard was added (m-fluorotoluene) a
sample analyzed by NMR.
According to the general procedure 9 was prepared from
cyclohaxanol (0.52 g, 5.2 mmol) and the crude fluorinating
mixture 1e + 2e (1.22 g 14 mmol of piperidine, 1.88 g,
14 mmol of pentafluoropropene) in chloroform (7 mL) at room
temperature. After stirring for 21 h, the appropriate amount of
NMR internal standard was added (m-fluorotoluene) and a
sample analyzed by NMR.
19F NMR (CDCl3, CFCl3): d ꢀ215.0 (tt, 1F, 2JHF = 48.1 Hz,
19F NMR (CDCl3, CFCl3): d ꢀ172.6 (m, 1F, CHF) [18].
3JHF = 23.3 Hz, CH2F) [8].
4.2.8. 2-Fluoropentane (7)
4.2.4. 1,1,1,2-Tetrafluoroethane (12)
According to the general procedure 7 was prepared from 2-
pentanol (0.45 g, 5 mmol) and the crude fluorinating mixture
1c + 2c (1.07 g 15 mmol of pyrrolidine, 2.2 g, 16 mmol of
pentafluoropropene) in chloroform (7 mL) at room tempera-
ture. After stirring for 17 h, the appropriate amount of NMR
internal standard was added (m-fluorotoluene) and a sample
analyzed by NMR.
According to the general procedure 2,2,2-trifluoroethanol
(3.905 g, 39 mmol) was added drop wise into a Carius tube with
solution of the fluorinating mixture 1b + 2b (9.607 g, 47 mmol)
in diethylether (10 mL) at ꢀ78 8C (dry ice/isopropanol). The
cooling bath was removed and the mixture was brought to room
temperature with magnet stirring. After stirring for 12 h, a
sample of the reaction mixture was subjected to low
temperature NMR analysis.
19F NMR (CDCl3, CFCl3): d ꢀ172.0 (m, 1F, CHF) [19].
1H NMR (CDCl3, CFCl3): d 4.89 (2H, dq, JHF = 21 Hz,
4.2.9. tert-Butyl fluoride (10)
2
3JHF = 7 Hz, H-2); 19F NMR (CDCl3, CFCl3): d ꢀ78.3 (dt, 3F,
According to the general procedure 9 was prepared from tert-
Butanol (0.38 g, 5.2 mmol) and the crude fluorinating mixture
1e + 2e (1.29 g 15 mmol of piperidine, 2.76 g, 28 mmol of
3
3JFF = 16 Hz, JFH = 8 Hz, CF3), ꢀ241 (tq, 1F, CH2F); bp
ꢀ26.1 8C [16].

H. Koroniak et al. / Journal of Fluorine Chemistry 127 (2006) 1245–1251
1251
pentafluoropropene) in chloroform (10 mL) at room tempera-
ture. After stirring for 21 h, the appropriate amount of NMR
internal standard was added (m-fluorotoluene) and a sample
analyzed by NMR.
(CDCl3): d ꢀ62.3 (t, 3F, 3JHF = 10.7 Hz, CF3); EI/MS (70 eV):
m/z (%) 197 (32) [M+], 114 (13) [M+ ꢀ C2H2F3], 111 (100)
[M+ ꢀ C4H8NO], 86 (29) [M+ ꢀ C3H2F3O], 83 (14) [M+ ꢀ C5
H8NO2]; mp 59–60 8C.
3
19F NMR (CDCl3, CFCl3): d ꢀ130.7 (m, 1F, JFH = 21 Hz,
CF) [15].
4.3.5. N-Piperidine-3,3,3-trifluoropropionamide (3e)
1H NMR (CDCl3): d 3.27 (2H, q, 3JHF = 10.2 Hz, H-2), 3.49
(2H, m, H-6), 3.67 (8H, m, H-4 and H-5); 13C NMR (CDCl3): d
38 (1C, q, 2JCF = 28.8 Hz, C-2), 42.0 (1C, t, C-6), 46.4 (2C, t, C-
5), 66.2 (2C, t, C-4), 123.5 (1C, q, 1JCF = 276.2 Hz, C-3), 161.4
(1C, d, C-1); 19F NMR (CDCl3): d ꢀ59.6 (t, 3F, 3JHF = 10.7 Hz,
CF3); EI/MS (70 eV): m/z (%) 194 (10) [M+ ꢀ 1], 179 (18)
[M+ ꢀ CH4], 110 (31) [M+ ꢀ C5H11N], 84 (100) [M+ ꢀ C3H2
F3O], 83 (5) [M+ ꢀ C6H10NO]; mp 75–85 8C.
4.3. 3,3,3-Trifluoropropionamides (3)
4.3.1. N,N-Dimethyl-3,3,3-trifluoropropionamide (3a)
3
1H NMR (CDCl3): d 3.2 (2H, q, JHF = 10.7 Hz, H-2), 3.3
(3H, s, H-5), 3.4 (3H, s, H-4); 13C NMR (CDCl3): 36.0 (1C, tq,
2JCF = 28.8 Hz, C-2), 38.3 (1C, q, C-5), 40.2 (1C, q, C-4), 123.4
1
(1C, q, JCF = 278.3 Hz, C-3), 160.9 (1C, m, C-1); 19F NMR
(CDCl3): d ꢀ63.2 (t, 3F, 3JHF = 10.7 Hz, CF3; EI/MS (70 eV):
m/z (%) 155 (39) [M+], 140 (15) [M+ ꢀ CH3], 111 (27)
[M+ ꢀ C2H6N], 83 (13) [111 ꢀ CO], 44 (17) [M+ ꢀ C3H2F3O].
References
´
[1] M. Hudlicky, A.E. Pavlath, Chemistry of Organic Fluorine Compounds,
vol. II, Washington, DC, 1995.
4.3.2. N,N-Diethyl-3,3,3-trifluoropropionamide (3b)
1H NMR (CDCl3): d 1.1 (3H, t, 3JHH = 7.2 Hz, H-7), 1.2 (3H,
[2] G.A. Olah, X.-Y. Li, in: G.A. Olah, R.D. Chambers, G.K.S. Prakash (Eds.),
Synthesis Fluorine Chemistry, Wiley, New York, 1992, p. 163.
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Org. Chem. 44 (22) (1979) 3872–3881.
3
3
t, JHH = 7.2 Hz, H-5), 3.2 (2H, q, JHF = 10.4 Hz, H-2), 3.3
3
3
(2H, q, JHH = 7.2 Hz, H-6), 3.4 (2H, q, JHH = 7.2 Hz, H-4);
13C NMR (CDCl3): d 12.9 (1C, q, C-7), 14.0 (1C, q, C-5), 36.0
(1C, tq, 2JCF = 29 Hz, C-2), 40.3 (1C, t, C-6), 42.4 (1C, t, C-4),
´
[4] W. Dmowski, R. Kolinski, Roczniki Chem. 47 (1973) 1211–1221.
[5] W.R. Hasek, W.C. Smith, V.A. Engelhardt, Org. Biol. Chem. 82 (1960)
543–551.
1
123.9 (1C, q, JCF = 276.2 Hz, C-3), 161.2 (1C, m, C-1); 19F
[6] L.S. German, S. Zemskow, New Fluorinating Agents in Organic Synth-
esis, Springer, New York, 1989, p. 254.
3
NMR (CDCl3): d ꢀ62.7 (t, 3F, JHF = 10.4 Hz, CF3); EI/MS
(70 eV): m/z (%) 183 (48) [M+], 168 (15) [M+ ꢀ CH3], 154 (12)
[M+ ꢀ C2H4], 140 (17) [M+ ꢀ C3H7] 111 (30) [M+ ꢀ C4H8N],
83 (9) [111 ꢀ CO], 72 (11) [M+ ꢀ C3H2F3O], 58 (100)
[C3H8N+].
[7] N. Ishikawa, H. Iwakiri, A. Takaoka, Bull. Chem. Soc. Jpn. 52 (11) (1979)
3377–3380.
[8] W.A. Petrov, S. Swearingen, W. Hong, W.C. Petersen, J. Fluorine Chem.
109 (2001) 25–31.
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[10] R.N. Haszeldine, J.R. McAllister, A.E. Tipping, J. Chem. Soc., Perkin
Trans. I (1975) 2015–2019.
4.3.3. N-Pyrrolidine-3,3,3-trifluoropropionamide (3c)
1H NMR (CDCl3): d 1.9 (4H, m, H-5), 3.2 (2H, q,
3JHF = 10.4 Hz, H-2), 3.5 (4H, m, H-4); 13C NMR (CDCl3): d
25 (2C, t, C-5), 39.0 (1C, tq, 2JCF = 28.8 Hz, C-2), 46.5 (2C, t,
´
[11] D.P. Cox, J. Terpinski, W. Ławrynowicz, J. Org. Chem. 49 (1984) 3216–
3219.
[12] S.V. Pasenek, M.E. de Roos, W.K. Appel, Tetrahedron 52 (8) (1996) 2977–
2982.
C-4), 123.5 (1C, q, 1JCF = 276.2 Hz, C-3), 161.2 (1C, C-1); 19
F
[13] C. Lai, Y. Kim, C.M. Wang, T.E. Mallow, J. Org. Chem. 58 (1993) 1393–
3
1399.
NMR (CDCl3): d ꢀ61.6 (t, 3F, JHF = 10.6 Hz, CF3); EI/MS
(70 eV): m/z (%) 181 (34) [M+], 153 (25) [M+ ꢀ C2H4], 111
(16) [M+ ꢀ C4H8N], 83 (9) [111 ꢀ CO], 70 (50) [M+ ꢀ C3H2
F3O]; mp 54–56 8C.
[14] H.J. Schneider, N. Gschwendtner, D. Heiske, V. Hoppen, F. Thomas,
Tetrahedron 33 (1977) 1769–1773.
[15] P. Barthazy, L. Hintermann, R.M. Stoop, Helv. Chim. Acta 82 (1999)
2448–2453.
[16] N. Igndt’ev, A. Kucherina, P. Sartori, Acta Chem. Scand. 53 (12) (1999)
1110–1116.
4.3.4. N-Morpholine-3,3,3-trifluoropropionamide (3d)
3
1H NMR (CDCl3): d 3.2 (2H, q, JHF = 10.2 Hz, H-2), 3.4
[17] D. Albanese, D. Landini, M. Penso, J. Org. Chem. 63 (1998) 9587–
9589.
(4H, m, H-4), 3.6 (4H, m, H-5); 13C NMR (CDCl3): d 38 (1C, q,
[18] H. Hayashi, H. Sonoda, K. Fukumura, T. Nagata, Chem. Commun. (2002)
1618–1619.
J
CF = 29.1 Hz, C-2), 42.2 (2C, t, C-4), 46.6 (2C, t, C-5), 123.5
(1C, q, JCF = 276.2 Hz, C-3), 161.4 (1C, d, C-1); 19F NMR
[19] F.J. Weigert, J. Org. Chem. 45 (17) (1980) 3476–3483.