292
Pd(CH3CN)2 (10 mol%)
PCy3 (20 mol%), K 2 CO 3 (3 equiv)
PivOH (40 mol%), DMF
MW, 140
o C, 45-60 min
I
R
N
N
Bn
CO 2 Me
AcHN
N
N
Bn
CO 2 Me
AcHN
R
Scheme 66 Regioselective synthesis of benzylated imidazole via C5–H arylation reaction of protected l-histidine
Pd(OAc)2 (1 mol%)
KOPiv (2.5 equiv)
DMAc (0.3 M)
MW, 80
o C, 30 min
C 8 H 17
C 8 H 17
C 8 H 17 C 8 H 17
C 8 H 17
C 8 H 17
Polymers with high
molecular weight of
48000-147000
Br
Br
O
O
S
N
S
C 9 H 19
N
S
C 9 H 19
or
Polymers:
S
O
O
n
n
N
S
C 9 H 19
N
S
C 9 H 19
Scheme 67 Microwave-assisted direct arylation condensation reaction of 3,4-(ethylenedioxy)
thiophene and 9,9-dioctyl-2,7-dibromofluorene for synthesis of polymers
Pd(dppf)Cl2 CH 2 Cl 2 (5 mol%)
PPh 3 (10 mol%)
Ag2 CO 3 (2 equiv)
4-CH 3 C 6 H 4 I (3.0 equiv)
H 2 O
MW, 115
o C, 1.5 h
S
N
NBn
HO
S
N
NBn
HO
Scheme 68 Microwave-assisted Pd-catalysed C5–H arylation of thiazoles
D. S. Deshmukh et al.