HF-mediated equilibrium between fluorinated ketones and the corresponding α-fluoroalcohols

Article abstract of DOI:10.1016/j.tet.2011.01.087

We have successfully obtained the first unambiguous spectroscopic proof of the structure of heptafluoropropan-2-ol by ¹³C NMR, which has been assumed from early 70s but without unequivocal evidence. Equilibrating relationship between fluorinated ketones and the corresponding hydrates as well as α-fluoroalcohols in anhydrous HF was at least qualitatively supported by our ab initio computation, and moreover, anhydrous HF as a convenient solvent was found to offer an effective new route for production of 1,1,1,3,3,3-hexafluoropropan-2-ol in industrial scales.

Full text of DOI:10.1016/j.tet.2011.01.087

Tetrahedron 67 (2011) 2215e2219
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
HF-mediated equilibrium between fluorinated ketones and the corresponding
a-fluoroalcohols
a
,
a
a
b
*
Tatsuya Hayasaka , Yutaka Katsuhara , Takashi Kume , Takashi Yamazaki
a
Chemical Research Center, Central Glass Co. Ltd., 2805 Imafuku-Nakadai, Kawagoe, Saitama 350-1151, Japan
Division of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
b
a r t i c l e i n f o
a b s t r a c t
Article history:
We have successfully obtained the first unambiguous spectroscopic proof of the structure of hepta-
fluoropropan-2-ol by C NMR, which has been assumed from early 70s but without unequivocal evi-
dence. Equilibrating relationship between fluorinated ketones and the corresponding hydrates as well as
Received 8 December 2010
Received in revised form 27 January 2011
Accepted 27 January 2011
Available online 3 February 2011
13
a
-fluoroalcohols in anhydrous HF was at least qualitatively supported by our ab initio computation, and
moreover, anhydrous HF as a convenient solvent was found to offer an effective new route for production
of 1,1,1,3,3,3-hexafluoropropan-2-ol in industrial scales.
Keywords:
Fluorinated ketones
Ó 2011 Elsevier Ltd. All rights reserved.
a
-Fluoroalcohols
Hydrates
Hydrogen fluoride
O
HO Z
X C CY3
1
. Introduction
+
HZ
X C CY3
3
3
In addition to their low chemical stability, prompt additione
elimination sequence of water or hydrogen halides to carbonyl
compounds generally renders isolation of 1,1-diols or 1,1-halohy-
drins1 (Scheme 1) difficult, respectively. The strong electron-
withdrawing trifluoromethyl groups in hexafluoroacetone (HFA,
1
2
(Z : F)
3
(Z : OH)
a : X=Y=F b : X=F, Y=H c : X=Y=H
1
a) are considered to enable formation of such unique structures by
Scheme 1. Addition−elimination sequence of water or hydrogen halides to carbonyl
effective electrophilicity enhancement of the carbonyl group, and
in fact our computation clearly demonstrated the large LUMO en-
ergy difference between 1a and 1,1,1-trifluoroacetone (TFA, 1b) or
acetone (1c) of 1.38 and 2.69 eV, respectively.
compounds.
as an alternative process for production of 1,1,1,3,3,3-hexa-
fluoropropan-2-ol 4 (HFIP) and for production of hexafluorobi-
sphenol A using 2a as the efficient substrate.
The fairly stable gem-diol 3a is known to be readily formed by
2
addition of water to 1a. However, heptafluoropropan-2-ol 2a is
3
4
believed to be obtained by treatment of 1a with anhydrous HF, to
the best of our knowledge, the corresponding -fluorohydrin 2a
was not isolated from an equilibrium mixture of 1a and HF and its
a
2. Results and discussion
1
a
3
,5
structure was not properly confirmed yet.
13C NMR spectrum of 1a in HF is shown in Fig. 1 along with the
ones of tri- and non-fluorinated acetones 1b and 1c in HF for com-
parison, respectively. Two sets of independent peaks were observed
We have envisaged that 13C NMR measurements in an anhydrous
HFsolventwould provideaclearandstraightforward solution onthe
structure of the adduct obtained by 1a and HF. In this paper are
for 1a in HFat
4.8 Hz) whose (1) J and J doublet coupling patterns, respectively
2) the chemical shift of the former peak, as well as (3) complete
d
98.6 (dsept, J¼244.4, 37.4 Hz) and 116.7 (qd, J¼285.0,
reported our successful NMR results for clarification of the
rohydrin framework and a novel HF-mediated equilibrium between
fluorinated ketones and the corresponding -fluoroalcohols as well
a-fluo-
1 2
3
(
a
disappearance of the HFA C]O peak at 173.0 ppm are the prominent
and unanimous indication of HF fluorine attacking the carbonyl
carbon atom of 1a to form a new C eF bond in 2a. On the other hand,
only ca. 30% of the HF adduct 2b was noticed for 1b with 70% intact,
and no HF incorporation was detected for 1c at all in spite of more
5
5
*
Corresponding author. Tel.: þ81 49246 3496; fax: þ81 49 243 4201; e-mail
address: tatsuya.hayasaka@cgco.co.jp (T. Hayasaka).
0
040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.01.087

2216
T. Hayasaka et al. / Tetrahedron 67 (2011) 2215e2219
C4 (6)
O
C
HO
F
2
C5
6
C5
X3C1 C Y X C
3
4
3
3
C Y
3
X=Y=F
C1
C4
C2
C5
C3
C6
X=F, Y=H
X=Y=H
C2
C1 (3)
240 220 200 180 160
130
120
110
100
90
30 20 10 ppm
Fig. 1. 13C NMR spectrum of HFA (1a), TFA (1b), and acetone (1c) in anhydrous HF at 24 ꢀC.
2
6
than 30 ppm exceeding downfield shift of the C peak possibly by
robust HF coordination to the carbonyl oxygen atom.
stable product 2a$2HF by 3.96 kcal/mol than the corresponding
complex. Considering that this TS was 5.05 kcal/mol lower than the
substrate pair of 1a and 3HF, formation of 2a by HF addition to 1a is
expected to proceed in a favorably exothermic manner. In the case
of 1b, although the activation energy was found to be almost in
a same level (16.02 and 16.83 kcal/mol) as the case of 1a, the def-
inite discrepancy was the energetic preference of the 1b$3HF
complexes to their products 2b$2HF by 2.08 and 1.43 kcal/mol.
Such trend became more pronounced for acetone 1c, and the
product 2c$2HF was destabilized by 5.52 kcal/mol. These results led
to strong expectation that, different from the case of 1a, both 1b
and 1c would be detected at least as the major components in re-
action mixtures, which were totally consistent with our NMR ob-
servation already shown in Fig. 1.
A part of these trends are qualitatively well elucidated on the
basis of the LUMO energy gap between these ketones as depicted
above, and for obtaining further theoretical support on such phe-
nomena, extensive computational analysis was carried out for both
2
HF and H O addition to the ketones 1a, 1b, and 1c. As shown in
Table 1, after a number of attempts, three HF molecules were found
to play a pivotal role in this reaction course, and HF coordination to
the ketones giving complex was proved to acquire 20e30 kcal/mol
energetic stabilization relative to the energetic sum of 1a and three
HF molecules. Magnitude of this gain seemed to be in an inversely
proportional to the number of fluorine atoms included in 1, which
would be the reflection of their different HOMO energy levels. After
passing through the eight-membered ring transition state (TS) with
Electrostatic characteristics as described above pertinently ac-
counts for in a similar manner why 1a readily forms the stable and
1
6.82 kcal/mol energy barrier, 1a was transformed into the more
7
easy-to-handle adduct like 3a. Ready availability of 3a led us to
confirm its behavior in various equivalents (n) of anhydrous HF
1
3
Table 1
whose C NMR spectra are collected in Fig. 2.
The peak at 88.4 ppm clearly exemplified retention of the gem-
Computational results for the formation of HF as well as H
nated ketones 1a, 1b, and 1c
2
O adducts with fluori-
d
a,b
diol structure of 3a when n¼3, and although the HF adduct 2a was
detected as the minor component with the HF amount of 10 equiv,
further introduction of HF until n¼30 rendered 2a as the exclusive
species. As shown in Table 1, the adduct 3a$2HF (product of
1
2
aþ2HFþH
2
O) is energetically more stable than the corresponding
a$2HF (product of 1aþ3HF), which is reflected to the NMR results
when n¼3 (Fig. 2). However, increase of the amount of Brønsted
acid HF would promote its coordination to water to significantly
diminish nucleophilic ability of the latter molecules. Thus, the
2
larger excess HF would result in stronger deactivation of H O by
effective protonation and give a higher chance for HF to attack at
the C]O group, leading to exclusive formation of 2a when n¼30.
This method was efficiently applied for dehydration of HFA hy-
8
drates and the resultant HF solution of HFA or 2a was readily
Relative energy (kcal/mol)
reacted with phenol to realize the industrial production of hexa-
Complex
TS
Product
8,9
fluorobisphenol A (Scheme 2).
1
1
1
1
1
1
1
1
aþ3HF
ꢁ21.87
ꢁ26.27
ꢁ26.27
ꢁ31.81
ꢁ22.54
ꢁ24.97
ꢁ24.96
ꢁ29.48
ꢁ5.05
ꢁ25.83
Until now, a couple of patents have mentioned about the ready
c
bþ3HF (anti)
ꢁ10.25
ꢁ9.44
ꢁ24.19
ꢁ24.84
ꢁ26.29
ꢁ30.89
ꢁ26.22
ꢁ26.84
ꢁ23.52
c
preparation of HFIP 4a by way of the transition metal-catalyzed
bþ3HF (syn)
cþ3HF
10
hydrogenation of HFA hydrate 3a. We reached to an idea that if
this reduction proceeded via the corresponding ketone 1a gener-
ꢁ19.14
ꢁ10.67
ꢁ10.67
ꢁ9.43
aþ2HFþH
2
O
O (anti)c
11
bþ2HFþH
2
2
ated during equilibration, the HFAeHF adduct 2a should be also
bþ2HFþH
O (syn)c
applicable as a substrate to the same protocol. Actually, subjection
cþ2HFþH
2
O
ꢁ13.59
of 2a to the standard Pd/C condition under a 1.0 MPa H
2
atmo-
a
Computation was carried out by Gaussian 03 W at the B3LYP/6-311þþG** level
sphere readily afforded 4a in only 2 h at ambient temperature with
of theory.
12,13
b
perfect product selectivity (Scheme 3).
On the basis of previous
Molecular models of 1aþ3HF were shown as the representative examples.
c
calculations, smaller energy gap between the product 2a$2HF and
the complex 1a$3HF (3.96 kcal/mol) required less extra energy by
syn and anti express the relative relationship between a CF
coordinated to the carbonyl oxygen.
3
group and HF

T. Hayasaka et al. / Tetrahedron 67 (2011) 2215e2219
2217
C1
C2
n=3
HO
OH
C1F
C2
C1
3a
C2
1
F3C
C3
3
C4
n=10
HO
F3C3 C3F
F
C4
2a
C3
3
C4
n=30
130
120
110
100
90
ppm
Fig. 2. 13C NMR spectrum of 3a$2H
O in HF (n equiv) at 24 C.
ꢀ
2
H O
OH
HF
HF
2
HO F
F3C CF3
CF3
OH
O
HO OH
F3C CF3
HF
HO F
F3C CF3
+
HO
2
F3C CF3
CF3
H O
2
2a
1a
3a
2a
Scheme 2. Synthesis of hexafluorobisphenol A.
Scheme 5. Equilibrium between 2a and 3a via 1a in HF.
3. Conclusions
O
We have successfully obtained the first and unequivocal spec-
HO F
F3C CF3
2a
a)
13
troscopic proof of the unique structure of 2a by C NMR, which has
F3C CH3
13
OH
F3C CF3
4a
estimated from early 70s but without decisive evidence. Our
C
1b
NMR spectra and ab initio computation supported equilibration
between 1 and 2 as well as 3 in anhydrous HF whose role as
a unique and convenient solvent was demonstrated by the effective
new production route of 4a in industrial scales.
OH
F3C CH3
4b
HO OH
F3C CF3
3a
b)
4
. Experimental section
ꢀ
ꢀ
Scheme 3. Preparation of HFIP (4a): (a) from 2a in HF, cat. Pd/C, H
2
, 1.0 MPa, 30 C, 2 h
(
(
4a: 99.9%, 4b: none, 1b: none); (b) from 3a in H
4a: 99.2%, 4b: 0.6%, 1b: 0.2%).
2
O, cat. Pd/C, H
2
, 0.5 MPa, 100 C, 6 h
4.1. General
Caution! Anhydrous HF can cause severe burns and contact with
skin must be avoided. Such effect of HF unfortunately prevented us
to obtain physical data except for NMR for materials in Section 4.2.
heating rather than the case between 3a$2HF and 1aþ2HFþH
2
O
(
8.35 kcal/mol). This milder conditions would prevent contamina-
tion of 1b as well as its further reduced material, 1,1,1-tri-
fluoropropan-2-ol 4b (Scheme 3).
All reagents and solvents were purchased and used without
15,16
further purification except for hexafluoroacetone (HFA)
hydrogen fluoride (HF), both of which produced by ourselves.
and
At the next stage, for obtaining further fundamental information
18
on the equilibration between 1a and 2a in HF, H
2
O (1 equiv) was
1
13
19
H NMR (400 MHz), C NMR (100 MHz), F NMR (376 MHz)
added to a mixture of 1a in HF (30 equiv). After 2 days at room
spectra were recorded using a JEOL AL-400 spectrometer at ambient
temperature using a fluorinated ethylene-propylenecopolymer(FEP)
tubing without spinning nor deuterated solvent lock. Chemical shifts
13
temperature, only 2a was observed by C was subjected to the
ꢀ
similar hydrogenation conditions at 0 C to furnish a 37/63 mixture
18
0
16
14
of HFIPe O (4 a)/HFIPe O (4a) quantitatively (Scheme 4). 37%
incorporation of 18O explicitly demonstrated the direct proof of the
equilibrium between 2a and 3a via 1a in an HF solvent. Thus, in
3 3
are reported in parts per million. CDCl (7.24 (from CHCl as impurity
in CDCl ) and 77.0 ppm) and CFCl (0.0 ppm) were used as external
3
3
1
13
19
standards for H, C, and F NMR spectra, unless otherwise stated. IR
spectra were run on a Thermo Nicolet FTIR NEXUS instrument. The
electron-impact mass spectra were recorded on a JEOL Automass 150
quadrupolmass spectrometer, andthe electronspray ionizationmass
spectra were recorded on an Appliedbiosystems Mariner time of
flight mass spectrometer, and the field ionization mass spectra were
recorded on a JEOL T100GC time of flight mass spectrometer.
spite of strong deactivation of the nucleophilic ability of H
2
O (or
18
H
2
O) by a large excess amount of HF, it appeared that there is still
16
apparent equilibrium between 1a and 3a affecting exchange of
O
18
and O (Scheme 5).
18OH
O
OH
F3C CF3
i) - iii)
+
F3C CF3
F3C CF3
4.2. NMR measurement of ketones (1) in excess amounts of
hydrogen fluoride (HF)
1a
4a
4a'
quant, 63 : 37
To a 100 mL stainless-steel autoclave cooled in an ice/water bath
were charged 30 g of hydrogen fluoride (1.5 mol) and 33.2 g of
hexafluoroacetone (0.2 mol) at 0 C, and 1 mL of the mixture was
2
Scheme 4. Reduction of 1a in presence of 30 equiv of HF and 1 equiv of H O: (i) HF
ꢀ
18
ꢀ
ꢀ
(
30 equiv), 0 C, 1 h; (ii) H
2
O (1 equiv), rt, 2 days; (iii) Pd/C, H
2
, 1.0 MPa, 0 C, 1 h.

2218
T. Hayasaka et al. / Tetrahedron 67 (2011) 2215e2219
transferred to an FEP NMR tubing cooled in an ice/water bath and
then the end of the tubing was heat-sealed.
hydrogen fluoride (6.95 mol), and 86 g of hexafluoroacetone
(0.52 mol) at 0 C, and the mixture was cooled in an ice/water bath.
ꢀ
The reaction vessel was flushed with nitrogen once and then with
4
.2.1. NMR of hexafluoroacetone (HFA, 1a) in HF. 1H NMR:
d
7.43 (s,
hydrogen twice. The reaction mixture was stirred under 1.0 MPa of
13
ꢀ
HF). C NMR:
J¼34.7, 285.0 Hz, CF
d
2a 98.6 (septd, J¼34.7, 244.4 Hz, CF
3
C), 116.7 (dq,
ꢁ197.9 (HF), ꢁ85.4 (s, 2a).
hydrogen with controlling the temperature between 0 and 25 C,
1
9
19
3
). F NMR:
d
whose F NMR with an FEP tubing clarified quantitative conver-
19
sion of HFA after 1 h (100% conversion and 99.9% selectivity by
F
5
4
.2.2. NMR of 1,1,1-trifluoroacetone (TFA, 1b) in HF. Colorless liq-
NMR). The resultant hexafluoropropan-2-ol was isolated by filtra-
ꢀ
1
uid. Bp 22 C. H NMR
d
1.8 (CH
1b$HF 15.4 (s, J¼24.8 Hz, CH
), 196.7 (q, J¼38.1 Hz, C]O). Compound 2b 20.3 (d, CH
3
, 2b), 2.7 (CH
), 113.7 (q, J¼286.9 Hz,
), 104.7
3
, 1b$HF), 8.2 (s, HF).
tion of a catalyst, neutralization of an aqueous solution by inorganic
13
1
C NMR:
CF
d
3
bases followed by distillation (76% yield). H NMR (CDCl
3
):
d
6.46 (s,
13
3
3
OH). C NMR (CDCl
3
):
d
70.3 (sept, J¼34.2 Hz, CeOH), 122.0 (q,
19
19
(
qd, J¼37.8, 229.0 Hz, CF
3
C), 118.9 (dq, J¼39.7, 267.3 Hz, CF
3
).
F
J¼289.1 Hz, CF
3
). F NMR (CDCl
3
):
d
ꢁ76.0 (s). IR (ATR, germa-
ꢁ
1
NMR:
d
ꢁ190.2 (HF), ꢁ90.0 (s, 2b), ꢁ83.1 (s, 1b$HF).
nium): 1377, 1286, 1180, 1103 cm . MS (EI) m/z (% rel int.): 129 (25),
þ
1
01 (29), 99 (100), 79 (28), 69 (21). HRMS (FI): M , found 168.0019.
.2.3. NMR of acetone (1c) in HF. 1H NMR:
6
d
1c$HF 3.3 (s, CH
C
3
H
2
F
6
O requires 168.0010.
4
3
), 9.1
13
(
s, HF). C NMR:
d
1c$HF 27.0 (CH
3
), 237.0 (C]O).
4
.7. Catalytic hydrogenation of hexafluoroacetone with
4
.3. HFA (1a) in excess amounts of H
2
O
heavy-oxygen water
1H NMR: 3a 4.50 (s, OH). 13C NMR:
d
d
3a 88.4 (sept, J¼33.2 Hz,
18O
To a 100 mL stainless-steel autoclave, 2.74 g (0.137 mol) of H
2
19
CF
3
C), 118.9 (q, J¼88.3 Hz, CF
3
). F NMR:
d
3a ꢁ83.4 (s). IR (ATR,
was charged and was frozen in a dry ice bath. A mixture of 82.2 g
4.11 mol) of HF and 22.74 g (0.137 mol) of HFA was then added and
the vessel was allowed to warm to room temperature with stirring.
ꢁ
1
germanium): 3700e3000, 1629, 1227, 1168, 1092 cm . HRMS (ESI):
(
ꢁ
[
MꢁH] , found 182.9865. C
3 1 6 2
H F O requires 182.9881.
18
This HFA/HF/H
2
O mixture (molar ratio: 1/30/1) was kept for 2
4
.4. Dehydration of hexafluoroacetone hydrate
days at room temperature and a small amount of the mixture was
used for measurement of NMR. In another 100 mL stainless-steel
autoclave, 1 g of 5% palladium on carbon (50% wet, 0.5 wt %,
To a 1 L PTFE (polytetrafluoroethylene) bottle with a PTFE dis-
tillation column (3 cm ID, 45 cm length) packed with PTFE Raschig
rings (4 mm) and a PTFE ice-water cooler on the top of the column,
was charged 220 g (1 mol) of hexafluoroacetone trihydrate
0
9
.23 mmol) was placed and evacuated. To this reaction vessel,
18
9.6 g of the HFA/HF/H
2
O mixture was charged and was cooled in
an ice/water bath. The reaction vessel was flushed with nitrogen
once and with hydrogen twice. The reaction mixture was stirred
and hydrogen was introduced so as to attain a pressure of 1.0 MPa
(
HFA$3H
freeze HFA$3H
2
O) and the bottle was cooled in dry-ice/acetone bath to
O, and then 272 g of hydrogen fluoride (13.6 mol)
2
was charged. The mixture was agitated by a magnetic stirrer and
was allowed to stand in a water bath, and then heated. From the top
of the column, a solution containing 2a and HF was distilled off at
ꢀ
and the temperature was kept between 0 and 10 C throughout the
19
hydrogenation reaction. Observation of the reaction mixture by
F
NMR in an FEP tubing clarified that the conversion of HFA and the
selectivity of the hydrogenation reaction were quantitative at the
end of the 1 h reaction period. The reaction mixture was poured
onto ice and was extracted with diisopropyl ether (IPE). An IPE
solution containing HFIP was used for GC/MS analysis. HRMS (FI):
ꢀ
the range of 14e20 C. The temperature of the still pot was raised
ꢀ
gradually and when it reached to 111 C, distillation was stopped.
The weight calculation, the acid titration, and the result of
KirleFischer Test showed that 389 g of the distillate contained
66 g (1 mol) of HFA and 223 g (11.15 mol) of HF without water, and
6 g of the residual liquid contained 54 g of water and 42 g of HF.
The yield was 98.6%. The identical NMR data to the one in Section
1
9
þ
16
þ
M , found 167.9998. C
3
H
2
F
6
O requires 168.0010. M , found
18
1
70.0032. C
3
H F
2 6
O requires 170.0052.
4
.2.1 were obtained for the obtained material.
4.8. Computational methods
4
.5. Preparation of hexafluorobisphenol A17
All calculations were performed with Gaussian03W19 (revision
B.03) at the B3LYP/6-311þþG** level of theory, and 0 (complex and
product) and 1 (TS) negative engenvalues were confirmed by fre-
quency calculation.
To a 1 L stainless-steel autoclave were charged 188 g (2 mol) of
phenol and 375 g of the distillate obtained in Section 4.4 consisting
of 160 g (0.96 mol) of HFA and 215 g (10.75 mol) of HF. The reaction
ꢀ
mixture was agitated and heated in an oil bath up to 110 C
Supplementary data
(
0.95 MPa) and kept for 6 h. The reaction mixture was poured onto
crashed ice, and precipitates are collected, filtered, washed with
water, and then dried to afford of hexafluorobisphenol A as a white
Supplementary data associated with this article can be found in
the online version at doi:10.1016/j.tet.2011.01.087.
ꢀ
1
powder (265 g, 82% yield, 99.1% purity). Mp 162 C. H NMR
CD OD):
4.88 (2H, s, OH), 6.76 (2H, d, J¼8.5 Hz, Ph), 7.16 (2H, d,
J¼8.5 Hz, Ph). C NMR (CD
(
3
d
13
OD):
d
64.9 (sept, J¼25.2 Hz, (CF
3
)
2
C),
).
References and notes
3
1
15.9, 125.5, 132.6, 158.9 (all s, aromatic), 125.9 (q, J¼286.3 Hz, CF
3
1
9
1. (a) Andreades, S.; England, D. C. J. Am. Chem. Soc. 1961, 83, 4670e4671. Hexa-
fluorocyclobutanone is known as the onlyone compound which reacts with HF to
give the distillable a-fluoroalcohol because of both CF2 groups attached to the
F NMR (CD
3
OD):
d
ꢁ63.8 (s, CF
3
). IR (ATR, germanium): 1516,
ꢁ1
þ
1
245, 1211, 1171, 1139 cm . MS (EI) m/z (% rel int.): 336 (M , 21),
2
67 (100), 227 (9), 199 (15), 197 (12), 169 (6), 99 (28). HRMS (FI):
carbonyl function, and/or partial release of the inherent strain by changing the
sp2 C]O group to the sp3 CF(OH) moiety; (b) Andreades, S.; England, D.C.;
Lindsey, R.V. Jr., U.S. Patent 3,030,409, 1962. a-Brominated alcohol was also re-
þ
M , found 336.0565. C15
H
10
F
6
O
2
requires 336.0585.
ported. See Clark, D. R.; Emsley, J.; Hibbert, F. J. Chem. Soc., Perkin Trans. 2 1988,
1107e1110.
. Yodis, A.W.Y.; Michener, A.W.; Karsay, B.I. Jr. U.S. Patent 3,544,633, 1970. Rep-
4
.6. Catalytic hydrogenation of hexafluoroacetone18
2
resentative physical properties of heptafluoropropan-2-ol are reported as fol-
lows: bp 14e16 C, mp ꢁ56 C (dec).
3. Lee, K.H. U.S. Patent 3,745,093, 1973.
To a 500 mL stainless-steel autoclave were charged 4.5 g of a 5%
ruthenium on carbon catalyst (50% wet, 1 wt %, 1.1 mmol), 139 g of
ꢀ
ꢀ

T. Hayasaka et al. / Tetrahedron 67 (2011) 2215e2219
. Simmons, H. E.; Wiley, D. W. J. Am. Chem. Soc. 1960, 82, 2288e2296 and ref-
15. Colorless gas. Bp ꢁ28
2219
ꢀ
13C NMR (CDCl
4
5
C
3
):
d
d
114.2 (q, J¼289.9 Hz, CF
3
), 172.9
1
9
erences sited therein.
(sept, J¼41.4 Hz, C]O). F NMR (CDCl
3
): ꢁ76.2 (s). IR (gas): 1807, 1341, 1273,
1218 cm . HRMS (FI): M , found 165.9864. C
16. Walker, N.; Fox, W. B.; De Marco, R. A.; Moniz, W. B. J. Magn. Reson. 1979, 34,
ꢁ
1
þ
. 1b was reported to be observed at 116.1 (CF3), 189.3 (C]O), and 24.4 (CH3) ppm
in CDCl3. See Abraham, R. J.; Jones, A. D.; Warne, M. A.; Rittner, R.; Tormena, C.
F. J. Chem. Soc., Perkin Trans. 2 1996, 533e539.
3 6
F O requires 165.9853.
295e299 13C NMR (CCl
) d 1a 114.4 (q, CF ), 173.0 (sept, C]O).
4 3
. C and C2 were reported to be observed at 30.7 and 206.7 ppm in CDCl3, re-
spectively. See Breitmaier, E.; Voelter, W. Carbon-13 NMR Spectroscopy, 3rd ed.;
VCH: Weinheim, 1987, pp 217.
1
17. Charles, J. P.; Jacqlynn, B.; The Aldrich Library of C and 1H FT NMR Spectra, 1st
13
6
ed.; Aldrich Chem Library: Milwaukee, 1993; Vol. 2, pp 323.
18. Charles, J. P.; Jacqlynn, B.; The Aldrich Library of 13C and 1H FT NMR Spectra, 1st
ed.; Aldrich Chem Library: Milwaukee, 1993; Vol. 1, pp 279.
7
. Cunningham, W.J.; Woolf, C. Fr. Patent 1,385,110, 1965.
8
9
. Katsuhara, Y.; Hayasaka, T.; Miyamoto, Y. JP. Patent 051799, 2009.
. Nishimiya, T.; Katsuhara, Y.; Fukui, A. JP. Patent 275295, 2010.
19. Frisch, M.J.; Trucks, G.W.; Schlegel, H.B.; Scuseria, G.E.; Robb, M.A.; Cheese-
man, J.R.; Montgomery, J.A. Jr.; Vreven, T.; Kudin, K.N.; Burant, J.C.; Millam, J.
M.; Iyengar, S.S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.;
Rega, N.; Petersson, G.A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.;
Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai,
H.; Klene, M.; Li, X.; Knox, J.E.; Hratchian, H.P.; Cross, J.B.; Bakken, V.;
Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R.E.; Yazyev, O.; Austin, A.
J.; Cammi, R.; Pomelli, C.; Ochterski, J.W.; Ayala, P.Y.; Morokuma, K.; Voth, G.
A.; Salvador, P.; Dannenberg, J.J.; Zakrzewski, V.G.; Dapprich, S.; Daniels, A.D.;
Strain, M.C.; Farkas, O.; Malick, D.K.; Rabuck, A.D.; Raghavachari, K.; Fores-
man, J.B.; Ortiz, J.V.; Cui, Q.; Baboul, A.G.; Clifford, S.; Cioslowski, J.; Stefanov,
B.B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R.L.; Fox, D.J.;
Keith, T.; Al-Laham, M.A.; Peng, C.Y.; Nanayakkara, A.; Challacombe, M.; Gill,
P.M.W.; Johnson, B.; Chen, W.; Wong, M.W.; Gonzalez, C.; Pople, J.A.;
Gaussian, Wallingford CT, 2004.
10. (a) Kawai, T.; Negishi, A. JP. Patent 81424, 1982. (b) Yokoi, K.; Iida, T. JP. Patent
2
6
04142, 1984. (c) Katsuhara, Y.; Nakamichi, T.; Kawai, T.; Nakasora, T. JP. Patent
9047, 1985. (d) Nishimiya, T.; Kumakura, M.; Kawai, T. JP. Patent 184025, 1994.
(
e) Okamoto, H.; Okazoe, T.; Watanabe, K.; Takagi, H. WO Patent 2002, 26679.
1. For example Catelani, G.; D’Andrea, F.; Guazzelli, L.; Pistar aꢀ , V. Carbohydr. Res.
009, 344, 717e724.
2. Katsuhara, Y.; Hayasaka, T.; Maruta, M. JP. Patent 051798, 2009.
3. There are some reports on the possible reduction directly from hydrates. See, (a)
1
2
1
1
Jiyannmari, K.; Dominitsuku, G. JP. Patent 2540409, 1996. (b) von Arx, M.; Mallat,
T.; Baiker, A. Angew. Chem., Int. Ed. 2001, 40, 2302e2305.
18
1
4. Calculation of the O content was carried out with referring to the following
report Abe, M.; Inakazu, T.; Munakata, J.; Nojima, M. J. Am. Chem. Soc. 1999, 121,
556e6562.
6