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1.4 Hz, 1H), 7.78 (ddd, J=8.2, 2.4, 1.3 Hz, 1H), 7.33 (ddd, J=8.2,
5.5, 0.7 Hz, 1H), 6.90 (s, 2H), 4.14 ppm (s, 6H); 13C NMR (126 MHz,
CDCl3): d=150.2, 149.1, 147.8, 138.1, 124.8, 123.1, 37.9 ppm; ele-
mental analysis calcd (%) for C10H12Cl3N3Pd: C 31.04, H 3.13, N
10.86; found: C 31.28, H 3.11, N 11.02.
Copper-promoted Hiyama coupling of IÀAr with various Ar-
Si(OEt)3 (Table 3)
Stock solutions were used to add accurate quantities of all re-
agents. If they were added independently, identical results were
obtained. A screw-capped Schlenk flask was charged with CuF2
(0.061 mmol) weighed in air as fast as possible. The solid was
stored under an N2 atmosphere in a flask equipped with a magnetic
stirrer bar. Under a strong current of N2, a separately prepared
stock solution (1 mL) in DMF, containing IÀAr (0.061 mmol), the ap-
propriate silane (0.12 mmol), and 5 (0.0012 mmol), was transferred
by syringe. The flask was heated at 110 8C until completion of the
reaction or specified time. All reactions were monitored by
19F NMR spectroscopy of samples taken under an N2 atmosphere.
Termination of the reaction and yields were determined by GC-MS
with PhÀPh as an internal standard for the reaction mixture or in-
tegration of 19F NMR spectra, if possible, of samples taken under
an N2 atmosphere. Good correlation was found in all cases. The
products could also be isolated after chromatography on silica gel
with hexane as the eluent.
[{PdCl(m-Cl)(IDM)}2] (7): In air, a flask was charged with PdCl2
(36 mg, 0.186 mmol) and [PdCl2(IDM)2] (68.4 mg, 0.186 mmol). The
mixture of solids was heated at reflux for 36 h in acetone (50 mL).
The solution was filtered through a pad of Celite. The crude prod-
uct and pad were washed with abundant boiling acetone (3
20 mL). The solvent was removed until 2 mL of acetone remained.
At this volume, fine orange crystals started to form. Slow addition
of hexane (30 mL) led to the formation of an orange solid (76 mg,
75%), which was filtered and dried under vacuum. 1H NMR
(500 MHz, CDCl3): d=6.89 (s, 2H), 4.19 ppm (s, 6H);13C NMR
(126 MHz, CDCl3): d=141.1, 123.4, 38.1 ppm; elemental analysis
calcd (%) for C10H16Cl4N4Pd2: C 21.96, H 2.95, N 10.24; found: C
22.12, H 3.01, N 10.43.
General procedure for the palladium-catalyzed Hiyama
cross-coupling reactions promoted by CuÀF complexes
Isolation of the organic products
Determination of the isolated yields was carried out by running
the reactions on twice the scale (0.122 mmol of aryl iodide). After
termination of the reaction, a 2m solution of KF (1 mL) was added
and the crude reaction mixture was heated at 110 8C for 1 h. A sa-
turated aqueous solution of NH4Cl was added until neutralization
(usually 2 mL). The aqueous phase was extracted with Et2O (3
10 mL). All organic layers were combined and dried over MgSO4.
The solvent was removed under reduced pressure and the sample
was dissolved in hexane and filtered through a short pad of silica
gel. After evaporation of the solvent, the product obtained was
usually pure. The products could also be isolated after chromatog-
raphy on silica gel with hexane as the eluent.
The organic products obtained in the catalytic cross-coupling reac-
tions were common products and reported elsewhere. In all cases,
the NMR chemical shifts matched those reported in the literature.
GC-MS analyses were used in all cases to confirm the expected mo-
lecular weight and structure. For NMR spectroscopy parameters,
see the Supporting Information.
Optimization of the Cu source (Table 1)
A screw-capped Schlenk flask was charged with the appropriate
amount of the Cu salt and the fluoride promoter specified in each
entry of Table 1. The solids were stored under an N2 atmosphere in
a flask equipped with a magnetic stirrer bar. Under a strong cur-
rent of N2, a separately prepared stock solution (1 mL) in DMF, con-
taining IÀPhÀCF3 (0.061 mmol), and MesSi(OEt)3 (0.12 mmol), and 3
(0.0012 mmol), was transferred by syringe. The flask was heated at
110 8C until completion of the reaction or specified time. All reac-
tions were monitored by 19F NMR spectroscopy of samples taken
under an N2 atmosphere. Yields of the reactions in Table 1 were de-
termined by integration of the 19F NMR spectra. The products
could also be isolated after chromatography on silica gel with
hexane as the eluent.
Mechanistic studies
Reaction of copper salts and (aryl)triethoxysilanes: The corre-
sponding Cu salt (10 mg) were added to an NMR tube. By using
a Schlenk adaptor for NMR tubes, the sample was kept under an
N2 atmosphere. Under a strong current of N2, DMF (0.5 mL), C6F5À
Si(OEt)3 (10 equiv), and CF3ÀPh (1 equiv) as an internal standard
were added by means of
a syringe. A capillary filled with
[D6]acetone was added and the NMR tube was closed and wrap-
ped with Teflon tape. The reaction was monitored by 19F NMR
spectroscopy.
Optimization of the Pd source (Table 2)
[(C6F5)Cu(DMF)] from CuF2: CuF2 did not react completely after
24 h at RT. Due to the presence of paramagnetic CuII, the signals in
the 19F NMR spectra were broad. The meta- and para-fluorine
atoms of [(C6F5)Cu(DMF)] overlapped with para- and meta-fluorine
atoms of (C6F5)Si(OEt)3 and C6F5H. The ortho fluorine atoms were
well resolved (see Figure S1 in the Supporting Information).
A screw-capped Schlenk flask was charged with the appropriate
amount of Pd catalyst (0.0012 mmol; and 0.0024 mmol of XPhos
for entry 1) specified in each entry of Table 2 and CuF2
(0.061 mmol) was weighed in air as fast as possible. The solids
were stored under an N2 atmosphere in a flask equipped with
a magnetic stirrer bar. Under a strong current of N2, a separately
prepared stock solution (1 mL) in DMF, containing IÀPhÀCF3
(0.061 mmol), and MesÀSi(OEt)3 (0.12 mmol) of, was transferred by
syringe. The flask was heated at 110 8C until completion of the re-
action or specified time. All reactions were monitored by 19F NMR
spectroscopy of samples taken under an N2 atmosphere. Yields of
reactions given in Table 2 were determined by integration of
19F NMR spectra. The products were isolated after chromatography
on silica gel with hexane as the eluent.
[(C6F5)Cu(bipy)] from [CuF2(bipy)]·3H2O: A quantitative yield, as
determined by NMR spectroscopy, was obtained by integration of
the meta-fluorine atoms with respect to the internal standard, PhÀ
CF3. The signal corresponding to the ortho-fluorine atoms was
broad due to fast relaxation (see Figure S2 in the Supporting Infor-
mation). 19F NMR (470 MHz, protic DMF, lock signal referenced to
an [D6]acetone capillary): d = À110.86 (brs, 2F), À164.53 (t, J(F,F)
= 19.2 Hz, 1F), À164.94 to À165.21 ppm (m, 2F).
Chem. Eur. J. 2016, 22, 4274 – 4284
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