75
were obtained. In addition, the palladium-catalyzed ortho-chlorination of anilides,
benzamides, and carbamates was also reported under solvent-free conditions [102].
Later, Xu and co-worker disclosed a Pd(OAc) 2 -catalyzed ortho-chlorination and
bromination of 2-arylpyrimidines using calcium halides as the halogen sources and
cupric trifluoroacetate as oxidant in the presence of air (Scheme 3.48) [103]. This
transformation displays high mono-selectivity and functional groups tolerance.
In addition, the oxidative C–H chlorination and bromination of arenes bearing
N-heteroarenes could also be achieved by copper catalysis in the presence of CrO 3
or O 2 as the oxidant and lithium halides as the halogen sources [104, 105].
Since 2012, Daugulis and co-workers demonstrated a variety of copper-mediated
or copper-catalyzed oxidative Csp
2
–H bond hetero-functionalization reactions
assisted by bidentate-directing groups [106]. In the presence of CuI as the catalyst
and AgF as the nucleophilic fluoride source, the auxiliary-assisted fluorination of
β-Csp
2
–H bonds of aminoquinoline benzamides and γ-Csp
2
–H bonds of benzylamine picolinamides occurred smoothly with excellent functional group tolerance,
which provided a straightforward way for the preparation of ortho-fluorinated benzoic acids via C−H functionalization under copper catalysis (Scheme 3.49) [107].
80%
67%
78%
Pd(OAc) 2 (5-10 mol%)
CuX 2 , Cu(OAc) 2
DCE, 90 °C, 48 h
H
Ar
NHR
X
Ar
NHR
Cl
NHAc
Cl
NHPiv
Cl
NHAc
Cl
NHAc
Me
MeO
79%
27%
95%
87%
Cl
NHAc
Cl
NAc
Br
NHAc
Br
NHAc
MeO
86%
Cl
Me
CO 2 Me
Scheme 3.47 Pd-catalyzed oxidative C–H chlorination and bromination of acetanilides
3 Oxidative Coupling Reactions Between Hydrocarbons and Organometallic Reagents…
were obtained. In addition, the palladium-catalyzed ortho-chlorination of anilides,
benzamides, and carbamates was also reported under solvent-free conditions [102].
Later, Xu and co-worker disclosed a Pd(OAc) 2 -catalyzed ortho-chlorination and
bromination of 2-arylpyrimidines using calcium halides as the halogen sources and
cupric trifluoroacetate as oxidant in the presence of air (Scheme 3.48) [103]. This
transformation displays high mono-selectivity and functional groups tolerance.
In addition, the oxidative C–H chlorination and bromination of arenes bearing
N-heteroarenes could also be achieved by copper catalysis in the presence of CrO 3
or O 2 as the oxidant and lithium halides as the halogen sources [104, 105].
Since 2012, Daugulis and co-workers demonstrated a variety of copper-mediated
or copper-catalyzed oxidative Csp
2
–H bond hetero-functionalization reactions
assisted by bidentate-directing groups [106]. In the presence of CuI as the catalyst
and AgF as the nucleophilic fluoride source, the auxiliary-assisted fluorination of
β-Csp
2
–H bonds of aminoquinoline benzamides and γ-Csp
2
–H bonds of benzylamine picolinamides occurred smoothly with excellent functional group tolerance,
which provided a straightforward way for the preparation of ortho-fluorinated benzoic acids via C−H functionalization under copper catalysis (Scheme 3.49) [107].
80%
67%
78%
Pd(OAc) 2 (5-10 mol%)
CuX 2 , Cu(OAc) 2
DCE, 90 °C, 48 h
H
Ar
NHR
X
Ar
NHR
Cl
NHAc
Cl
NHPiv
Cl
NHAc
Cl
NHAc
Me
MeO
79%
27%
95%
87%
Cl
NHAc
Cl
NAc
Br
NHAc
Br
NHAc
MeO
86%
Cl
Me
CO 2 Me
Scheme 3.47 Pd-catalyzed oxidative C–H chlorination and bromination of acetanilides
3 Oxidative Coupling Reactions Between Hydrocarbons and Organometallic Reagents…