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B(OH)
2
PdCl
2
(PCy
3
)
2
(3 mol%)
K
2
CO
3
, THF
Ph
Ph
Ph
Ph
N
N
Br
N
Br
O
O
O
120 °C, CO (5 bar), 30 h
26%
63%
90 °C, CO (50 bar), 110 h
81%
18%
O
Br
Br
B(OH)
2
PdCl
2
(PCy
3
)
2
(3 mol%)
K
2
CO
3
, THF
Ph
Ph
Ph
Br
N
N
N
O
O
120 °C, CO (5 bar), 2 h
83%
81%
120 °C, CO (5 bar), 42 h
Scheme 10.54 Pd-catalysed Suzuki carbonylation of halopyridines.
R'
R'
PdCl
2
(PPh
3
)
2
(5 mol% )
K
2
CO
3
,CO(5bar),THF
O
R"
R"
Cl
Ph
B (OH)
2
5examples
48-78 %
50 °C, 15 h
Cr (CO )
3
Cr (CO )
3
R'
R'
PdCl
2
(PPh
3
)
2
(5 mol% )
K
2
CO
3
,CO(5bar),THF
50 °C, 15 h
O
O
8examples
43 -96%
R"
R"
Cl
In
N
Cr (CO )
3
Cr (CO )
3
Scheme 10.55 Pd-catalysed
carbonylative
coupling
of
chloroarene-Cr(CO)
3
complexes.
In 2001, Castanet and co-workers demonstrated that in a palladium-
catalysed carbonylative Suzuki reaction, pyridine halides react with aryl-
boronic acids to give 2-pyridyl ketones in good yields (81-95%)
(Scheme 10.54).
67a
The proper choice of solvent, catalyst precursor and CO
pressure permitted the selective transformation of mono- and dihalopyr-
idines. Later, they extended this methodology to pyridine chlorides by ap-
plying an NHC ligand and Cs
2
CO
3
as base.
67b
Schmalz and co-workers investigated the carbonylative Suzuki reaction of
chloroarene-Cr(CO)
3
complexes with phenylboronic acid.
68
Using
PdCl
2
(PPh
3
)
2
as catalyst precursor, benzophenone derivatives were obtained
in good yields (Scheme 10.55). Palladium-catalysed carbonylative cross-
methylation reactions of different chloroarene-Cr(CO)
3
complexes mediated
by a stabilized dimethylindium(III) reagent were also described.
The palladium-catalysed carbonylative coupling of aryldiazonium ions
with arylboronic acids was published in 2002.
69
Various aryl ketones were
produced in moderate to high yields under mild conditions (Scheme 10.56).
One benefit of applying aryldiazonium ions as electrophiles is the potential
to perform coupling reactions under base-free conditions. Both electron-
donating and electron-withdrawing substituents on the aryldiazonium did
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