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Pd (PPh
3
)
4
(3 mol%)
aq ueous Cs
2
CO
3
toluene, 110 °C
CO (1 bar)
O
B(OH)
2
I
10 examples
55 -88%
Fe
Fe
Ar
R
Scheme 10.62 Pd-catalysed carbonylative coupling of iodoferrocene.
N
N
O
I
Pd
PPh
3
I
I
1mol%
9 examples
85-98 %
NaBPh
4
K
2
CO
3
, dioxane
CO (1 bar), 100 °C
R
R
O
I
9 examples
76-90%
PhB(OH)
2
R
R
Scheme 10.63 NHC-Pd-catalysed carbonylative coupling of aryl iodides.
iPr
iPr
R
1
R
1
O
N
N
PEPPS I-iPr (3 mol%)
Cs
2
CO
3
, chlorobenzene
CO (1 bar), 80 °C
I
B(OH)
2
Cl
Cl
Pd
N
R
4
iPr
iPr
R
2
R
4
R
2
R
3
R
3
9 examples
33 -98%
P EPPSI-iPr
Scheme 10.64 Pd-catalysed carbonylative coupling of ortho-disubstituted aryl
iodides.
NHC-palladium complexes as ecient catalysts for carbonylative Suzuki
coupling of aryl iodides with organoboranes were reported by Xia and co-
workers.
78
Aryl ketones were produced in high yields under mild conditions
(Scheme 10.63). Interestingly, both NaBPh
4
and ArB(OH)
2
could be used as
phenylating reagent.
Ortho-disubstituted aryl iodides, as representative examples of sterically
hindered compounds, are more challenging substrates in palladium-cata-
lysed coupling reactions. In this respect, it is interesting that Martin and co-
workers reported a synthesis of sterically hindered aryl ketones by using the
NHC-palladium complex PEPPSI-iPr.
79
Several diaryl ketones were produced
in moderate to good yields by this method (Scheme 10.64).
In 2008, Beller and co-workers developed a general method for diaryl ke-
tone synthesis by palladium-catalysed carbonylative coupling of aryl brom-
ides with arylboronic acids.
80
The combination of Pd(OAc)
2
and BuPAd
2
allowed the coupling of aryl/heteroaryl bromides with arylboronic acids to
give a broad range of ketones in good yields (Scheme 10.65). With this
catalyst in hand, they were able to synthesize suprofen, a non-steroidal anti-
inflammatory drug.
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