S. Calleja et al. / Journal of Fluorine Chemistry 126 (2005) 1493–1495
1495
implies a favoured six centres concerted reaction between
4.2.2. Metal oxides
CuO 0.8 g; ZrO2: 1.07 g; TiO2: 0.8 g; ZnO: 0.81 g;
Al2O3: 1.02 g.
the salts or metal oxides and the iodoacetate group.
Although no evidence of such process can be given at this
stage, it proposes a reasonable explanation for the
unexpected activation effect generated by these simple
alkali metals and metal oxides.
RFCH2CHO compounds prepared in this manuscript are
all known and characterized in the literature [11,13,14]. The
following data were collected to confirm their synthesis and
isolation as pure products:
3. Conclusion
C4F9CH2CHO: bp 75 8C; y(C O) 1740 cmÀ1; 1H NMR
(CDCl3) d 3.1 (t, 2H), 9.8 (s,1H); 19F NMR (CDCl3) d
À81.9 (m,3F), À110.3 (m,2F), À123.4, À125.8 (m,4F).
C6F13CH2CHO: bp 142 8C; y(C O) 1740 cmÀ1; 1H NMR
(CDCl3)d3.1(t,2H),9.8(s,1H);19FNMR(CDCl3)dÀ81.6
(m,3F), À110.3 (m,2F), À122.0, À122.8, À126.2(m,8F).
NMR (CDCl3) d 3.1 (t,2H), 9.8 (s,1H); 19F NMR (CDCl3)
d À81.5 (m,3F), À110.2 (m,2F), À121.8, À122.5,
À122.9, À126.2 (m,12F).
The conversion of 1-acetoxy-1-iodo-2-perfluoroalkyl-
ethanes into perfluoroalkylethanals was performed in good
yields using alkali halides dissolved in water. The best
results were obtained when sodium bromide was used at an
optimum concentration of 5.13 mol lÀ1. Metal oxides were
found to be poorly active in the presence of water, but
moderate to good yields were obtained under neat
conditions. This relatively simple protocol presents the
advantages of using cheap and commercially available
reactants and, in the case of alkali halides, water as an eco-
friendly solvent.
C8F17CH2CHO: bp 176 8C; y(C O) 1740 cmÀ1 1H
;
Acknowledgement
The authors thank Dr. G. Calleja for his useful comments
and assistance in the revision of this manuscript.
4. Experimental
References
4.1. Materials and instruments
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3370–3371.
RFI starting materials were gracefully provided by former
company Elf Atochem. AIBN was purchased from Acros.
Alkali metals and metal oxides were reagent grade and
purchased from Aldrich. NMR spectra were recorded on a
BRUCKER AC 250 spectrometer at 235,36 MHz (19F) and
250,13 MHz (1H). In 19F NMR, chemical shifts were
counted negatively from CFCl3 with increasing field, and in
1H NMR, they were counted positively from SiMe4 with
decreasing field. They are expressed in ppm.
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4.2. Synthesis
In
a typical experiment, RFCH2CHIOAc (5.32 g,
0.01 mol) was added to an aqueous solution (20 mL) of
NaF (4.2 g, 0.1 mol). The heterogeneous mixture was heated
to 100 8C for 24 h, during which time the conversion was
monitored by 19F NMR. Then, the reaction mixture was
allowed to cool down to room temperature and the organic
phase was isolated and washed twice with water
(2 Â 250 mL), once with a solution of sodium thiosulfate
10 wt% (250 mL), and twice with water (2 Â 250 mL). The
organic phase was collected and dried over sodium sulphate
and distilled under atmospheric pressure.
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4.2.1. Alkali halides
NaCl: 5.85 g; NaBr: 10.3 g; NaI: 15 g; KF: 5.81 g; KCl:
7.45 g; KBr: 11.9 g; KI: 16.6 g; LiF: 2.6 g; LiCl: 4.2 g; LiBr:
8.7 g; LiI: 13.4 g; NaCl: 5.85 g; C8F17SO3Li: 0.506 g
(0.001 mol).
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