CuI-catalyzed coupling of o-bromobenzylamines 208 with L-proline at 110
C
afforded pyrrole-fused 1,4-benzodiazepin-3-ones 209 directly (Scheme 73) [118].
Other amino acids were found suitable for N-arylation reaction, but did not give
cyclization products directly. However, through treatment of the coupling mixture
with diphenylphosphoryl azide (DPPA), the desired 1,4-benzodiazepin-3-ones 210
could be prepared in 35–60% yields.
16 Conclusion and Outlook
In this chapter, we have described some newly developed methods for assembling
N-containing heterocycles, which highly relied on Pd- or Cu-catalyzed N-arylation
and N-vinylation. These heterocycles include indoles, benzimidazoles, pyrroles,
indazoles, indolines, lactams, quinazolinones and heterobenzazepines. Some of
these new methods may find a number of applications in organic synthesis because
they provide powerful approaches for preparing N-containing heterocycles from
conveniently available starting materials in mild conditions. Further studies are
still needed to extend the reaction scope of these methods and discover new
approaches for synthesizing N-containing heterocycles.
References
1. Moody CJ (ed) (1998) Advances in nitrogen heterocycles. JAI, Stamford
2. Kotschy A, Timari G (eds) (2005) Heterocycles from transition metal catalysis. Springer,
Berlin
Scheme 72 Synthesis of phenothiazines via a CuI/L-proline-catalyzed cascade C–S and C–N
bond formation process
Scheme 73 Synthesis of pyrrole-fused 1,4-benzodiazepin-3-ones via CuI-catalyzed coupling of
o-bromobenzylamines and amino acids
Assembly of N-Containing Heterocycles via Pd- and Cu-Catalyzed C–N Bond. . .
115
C
afforded pyrrole-fused 1,4-benzodiazepin-3-ones 209 directly (Scheme 73) [118].
Other amino acids were found suitable for N-arylation reaction, but did not give
cyclization products directly. However, through treatment of the coupling mixture
with diphenylphosphoryl azide (DPPA), the desired 1,4-benzodiazepin-3-ones 210
could be prepared in 35–60% yields.
16 Conclusion and Outlook
In this chapter, we have described some newly developed methods for assembling
N-containing heterocycles, which highly relied on Pd- or Cu-catalyzed N-arylation
and N-vinylation. These heterocycles include indoles, benzimidazoles, pyrroles,
indazoles, indolines, lactams, quinazolinones and heterobenzazepines. Some of
these new methods may find a number of applications in organic synthesis because
they provide powerful approaches for preparing N-containing heterocycles from
conveniently available starting materials in mild conditions. Further studies are
still needed to extend the reaction scope of these methods and discover new
approaches for synthesizing N-containing heterocycles.
References
1. Moody CJ (ed) (1998) Advances in nitrogen heterocycles. JAI, Stamford
2. Kotschy A, Timari G (eds) (2005) Heterocycles from transition metal catalysis. Springer,
Berlin
Scheme 72 Synthesis of phenothiazines via a CuI/L-proline-catalyzed cascade C–S and C–N
bond formation process
Scheme 73 Synthesis of pyrrole-fused 1,4-benzodiazepin-3-ones via CuI-catalyzed coupling of
o-bromobenzylamines and amino acids
Assembly of N-Containing Heterocycles via Pd- and Cu-Catalyzed C–N Bond. . .
115