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
ꢀ
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
ꢀ
ꢀ