Pd-catalyzed intramolecular aryl amination could be applied in elaboration
of dibenzo[b,e][1, 4]diazepines 161, started from aryl iodides 160. This method
is also suitable for the synthesis of benzopyrido-analogues, as demonstrated by
transformation from aryl chloride 162 to cyclization product 163 (Scheme 55) [97].
11 Carbazoles and Related Heterocycles
The double N-arylation of 2,2
0 -dihalobiphenyl compounds 164 with primary
amines occurred under the catalysis of Pd(dba) 2 /tBu 3 P, delivering polysubstituted
carbazoles 165 (Scheme 56) [98]. 2,2
0 -Bibromobithiophene was also suitable for
the reaction, producing heterocarbazole 166 with 35% yield. This method has been
applied in the total synthesis of murrastifoline-A, a biscarbazole alkaloid, via
coupling of dibromide 167 with aryl amine 168 (Scheme 57) [99].
Ackermann et al. found that a domino amination/C–H bond activation process
could be used for the preparation of carbazoles 169 (Scheme 58) [100]. The readily
available anilines and 1,2-dihaloarenes make this method suitable for diverse synthesis.
Scheme 56 Synthesis of polysubstituted carbazoles via Pd-catalyzed double N-arylation
Scheme 55 Elaboration of dibenzo[b,e][1,4]diazepines and benzopyrido-analogues via Pd-catalyzed
intramolecular aryl amination
Assembly of N-Containing Heterocycles via Pd- and Cu-Catalyzed C–N Bond. . .
109
of dibenzo[b,e][1, 4]diazepines 161, started from aryl iodides 160. This method
is also suitable for the synthesis of benzopyrido-analogues, as demonstrated by
transformation from aryl chloride 162 to cyclization product 163 (Scheme 55) [97].
11 Carbazoles and Related Heterocycles
The double N-arylation of 2,2
0 -dihalobiphenyl compounds 164 with primary
amines occurred under the catalysis of Pd(dba) 2 /tBu 3 P, delivering polysubstituted
carbazoles 165 (Scheme 56) [98]. 2,2
0 -Bibromobithiophene was also suitable for
the reaction, producing heterocarbazole 166 with 35% yield. This method has been
applied in the total synthesis of murrastifoline-A, a biscarbazole alkaloid, via
coupling of dibromide 167 with aryl amine 168 (Scheme 57) [99].
Ackermann et al. found that a domino amination/C–H bond activation process
could be used for the preparation of carbazoles 169 (Scheme 58) [100]. The readily
available anilines and 1,2-dihaloarenes make this method suitable for diverse synthesis.
Scheme 56 Synthesis of polysubstituted carbazoles via Pd-catalyzed double N-arylation
Scheme 55 Elaboration of dibenzo[b,e][1,4]diazepines and benzopyrido-analogues via Pd-catalyzed
intramolecular aryl amination
Assembly of N-Containing Heterocycles via Pd- and Cu-Catalyzed C–N Bond. . .
109