Abstract
The palladium-catalyzed intramolecular N-arylation of the Blaise
reaction intermediate, formed by reaction of nitriles with an in
situ generated Reformatsky reagent from ethyl α-bromo-α-(2-bromophenyl)acetate
and zinc, afforded indoles in good yields. Extension of this approach
to the chemoselective intramolecular N-alkylation/palladium-catalyzed
N-arylation of the Blaise reaction intermediate, having ω-chloroalkyl
appendages, provided a novel route for the tandem one-pot synthesis
of N-fused indole derivatives. In contrast, the intermolecular coupling
reaction of the Blaise reaction intermediates with 1,2-dihalobenzene
did not proceed in the presence of a palladium catalyst, but proceeded
in the presence of copper(I) iodide as the catalyst and resulted
in indoles.
1 Introduction
2 Results and Discussion
2.1 Palladium-Catalyzed Intramolecular C-N Coupling
Reaction of the Blaise Reaction Intermediate
2.2 Chemoselective Intramolecular N-Alkylation/Palladium-Catalyzed
C-N Coupling Reaction of the Blaise Reaction Intermediate
2.3 Copper-Catalyzed Intermolecular N-C/C-C
Coupling Reaction of the Blaise Reaction Intermediate
with 1,2-Dihaloarenes
3 Conclusion
Key words
tandem reaction - Blaise reaction - palladium - copper - coupling - indoles
