Gianluca Pozzi et al.
FULL PAPERS
heptadecafluoro-1-decene (3.57 g, 8.00 mmol) in BTF
(2 mL) was added and the mixture was stirred for 20 h
under nitrogen at 908C. The reaction mixture was then
cooled to room temperature and the volatiles removed
under reduced pressure. The brown residue was taken up in
Et2O (100 mL), washed with H2O (320 mL) and dried
over MgSO4. The solvent was evaporated at reduced pres-
sure affordinga sticky dark-brown solid that was purified by
column chromatography (silica gel, AcOEt) affording
4,4’,5,5’-tetra(1H,2H-heptadecafluorodecen-1-yl)dibenzo-18-
crown-6 ether that was pure enough for further reactions;
yield: 0.364 g(17%, mostly the all- trans C=C isomer).
1H NMR (300 MHz, CDCl3): d=4.02 (m, 8H), 4.23 (m,
8H), 5.92 (dt, JH,H =16.3 Hz, JH,F =12.5 Hz, 4H), 6.90 (s,
4H), 7.29 (dt, JH,H =16.3 Hz, JH,F =2.5 Hz, 4H); 13C NMR
(75.4 MHz, CDCl3): d=69.2, 70.2, 112.2, 105.1–120.9 (m,
RF), 117.5 (t, JC,F =23.1 Hz), 127.1, 136.9 (t, JC,F =9.2 Hz),
rous layers were evaporated under reduced pressure afford-
inga brown paste (0.463) g containing4,4
’,5,5’-tet-
ra(1H,2H,3H,3H-heptadecafluoroundecen-1-yl)dibenzo-18-
crown-6 ether [all-trans C=C isomer, 1H NMR (300 MHz,
CDCl3): d=3.01 (m, 8H), 4.02 (m, 8H), 4.19 (m, 8H), 5.83
(dt, JH,H =15.8 Hz, JH,H =7.2 Hz, 4H), 6.75 (d, JH,H =15.8 Hz,
4H), 6.86 (s, 4H)] contaminated by fluorinated by-products.
To this crude compound dissolved in BTF/MeOH (30 mL/
5 mL), 10% Pd/C (0.232 g) was added. The mixture was
stirred for 3 h under atmospheric pressure of H2, then it was
filtered through a celite plug. The clear filtrate was evapo-
rated under reduced pressure affordinga pale brown solid
that was purified by column chromatography (silica gel,
CH2Cl2/MeOH, 95/5) followed by crystallization from isooc-
tane (10 mL). The title compound was obtained as an off-
white solid; overall yield: 0.424 g(38%); mp 94–96 8C.
1H NMR (300 MHz, CDCl3): d=1.84 (m, 8H), 2.07 (m,
8H), 2.60 (t, JH,H =8.1 Hz, 8H), 4.00 (m, 8H), 4.15 (m, 8H),
6.65 (s, 4H); 13C NMR (100.5 MHz, CDCl3): d=22.3, 30.9 (t,
150.6; 19F NMR (282 MHz, CDCl3): d=À81.2 (t, JF,F
=
9.8 Hz, 12 F), À111.4 (m, 8 F), À121.8 (br s, 8 F), À122.4 (br
s, 16 F), À123.2 (br s, 8 F), À123.6 (br s, 8 F), À126.6 (m, 8
F).
J
C,F =23.4 Hz), 31.8, 69.7, 70.4, 105.0–118.5 (m, RF), 115.8,
131.7, 147.8; 19F NMR (282 MHz, CDCl3,): d=À81.2 (t,
To a solution of 4,4’,5,5’-tetra(1H,2H-heptadecafluoro-1-
decenyl)dibenzo-18-crown-6 ether (0.215 g, 0.100 mmol) in
BTF/MeOH (30 mL/5 mL) 5% Pd/C (0.212 g) was added.
The mixture was stirred for 6 h under atmospheric pressure
of H2, then it was filtered through a celite plug. The clear fil-
trate was evaporated under reduced pressure affordinga
pale yellow solid that was purified by column chromatogra-
phy (silica gel, AcOEt) followed by washing with ice-cold
Et2O (5 mL). The title compound was obtained as an off-
J
F,F =9.3 Hz, 12 F), À114.4 (m, 8 F), À122.3 (m, 24 F),
À123.1 (br s, 8 F), À123.8 (br s, 8 F), À126.5 (m, 8 F); anal.
calcd. for C64H44F68O6 (2200.92): C 34.93, H 2.02; found: C
34.82, H 2.21%.
Determination of Partition Coefficients P
A 10-mL vial equipped with a magnetic stirrer was charged
with the fluorous-crown Rf-CE (45 mg), PFDMC (2.0 mL)
and the organic solvent (2.0 mL). The mixture was thermo-
stated at 308C, vigorously stirred for 0.5 h and then cooled
to room temperature and allowed to stand for 15 min for
the phases to separate. A 1.0-mL sample was taken out of
each phase, evaporated to dryness under vacuum and weigh-
ed on an analytical balance. The partition coefficient P was
determined as the ratio between the weight of the fluorous
phase residue and the weight of the organic phase residue.
1
white solid; yield: 0.161 g(75%); mp 124–125 8C. H NMR
(300 MHz, CDCl3): d=2.25 (m, 8H), 2.81 (m, 8H), 3.99 (m,
8H), 4.15 (m, 8H), 6.67 (s, 4H); 13C NMR (100.5 MHz,
CDCl3): d=22.9, 33.0 (t, JC,F =23.1 Hz), 69.3, 70.0, 115.4,
105.0–118.5 (m, RF), 129.6, 148.0; 19F NMR (282 MHz,
CDCl3,): d=À81.3 (t, JF,F =9.8 Hz, 12 F), À115.0 (m, 8 F),
À122.2 (m, 24 F), À123.2 (br s, 8 F), À123.9 (br s, 8 F),
À126.6 (m, 8 F); anal. calcd. for C60H36F68O6 (2144.82): C
33.60, H 1.69; found: C 33.43, H 1.81%.
Alkali Metal Picrate Extraction
The classical Frensdorffꢁs procedure, as modified by Kikuchi
and Sakamoto, was adapted.[25] Aqueous solutions were pre-
pared that contained the alkali metal picrate (1.010À4 M)
and the correspondingalkali metal chloride (1.010 À1 M).
Into a stoppered test tube was placed 3.0 mL of the aqueous
metal picrate solution and 3.0 mL of a 1.010À4 M solution
of CE in the proper solvent. The biphasic mixture was
stirred for 0.5 h at 258C. The sample was allowed to stand
for 2 h at the same temperature to allow complete phase
separation. The absorbance of the picrate in the aqueous
phase was measured at 356 nm with a UV-Visible spectro-
photometer. The percentage of picrate extracted into the
non-aqueous phase was calculated by: % Extraction=100
(Abs0ÀAbs)/Abs0 where Abs0 is the absorbance of a sample
of the unextracted metal picrate aqueous solution and Abs
is the absorbance of aqueous layer after extraction. Three
independent extractions were performed for each combina-
tion of metal picrate and crown ether, and the results were
averaged.
4,4’,5,5’-Tetra(1H,1H,2H,2H,3H,3H-heptadecafluoro-
undecyl)dibenzo-18-crown-6 Ether (Rf-CE3)
4,4’,5,5’-Tetraiododibenzo-18-crown-6
ether
(0.433 g,
0.501 mmol), Pd(OAc)2 (0.0402 g, 0.180 mmol), NaHCO3
ACHTREUNG
(0.422 g, 5.02 mmol), Bu4NHSO4 (0.679 g, 2.00 mmol) and
crushed 4 molecular sieves (1.62 g) were transferred
under nitrogen into a flame-dried Schlenk flask. Dry DMF
(12 mL) and BTF (4 mL) were added and the resultingsus-
pension was carefully degassed (vacuum/nitrogen3). A de-
gassed solution of 1H,1H,2H,3H,3H-heptadecafluoro-1-un-
decene (3.68 g, 8.00 mmol) in BTF (4 mL) was added and
the mixture was stirred for 24 h under nitrogen at 1058C.
The reaction mixture was then cooled to room temperature
and diluted with BTF (50 mL). The mixture was filtered
through a celite plug and the solid residue was washed with
BTF (315 mL). The combined liquid layers were washed
with H2O (320 mL). The solid formed was discarded and
the clear liquid phase was dried over MgSO4 and evaporated
under reduced pressure to give a sticky brown residue
(1.04 g) that was dissolved in CH2Cl2 (10 mL). The solution
was extracted with PFDMC (315 mL). The combined fluo-
2434
ꢀ 2008 Wiley-VCH VerlagGmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2008, 350, 2425 – 2436