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Azabicyclo[3.2.0]heptan-7-ones (carbapenams) from pyrrole
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Orientador(es)
Resumo(s)
The azabicyclo[3.2.0]heptan-7-ones 4, 10, 16 and 24 have been prepared from pyrrole. The same general
approach has been used for all these derivatives; namely, substitution of pyrrole at the 2- and 5-carbon
atoms, catalytic hydrogenation to produce pyrrolidine-2-acetic acid derivatives, and cyclisation
using tris(1,3-dihydro-2-oxobenzoxazol-3-yl)phosphine oxide 6. The catalytic hydrogenation of
2,5-disubstituted pyrroles gives only the corresponding cis-2,5-disubstituted pyrrolidines. The
hydrogenation proceeds more easily when the nitrogen atom bears a tert-butoxycarbonyl substituent.
The N-tert-butoxycarbonylpyrroles 8 and 21 bearing an á-substituent in the acetate side chain were
hydrogenated with a high degree of facial stereoselectivity. This allowed the 6-phthalimidoazabicyclo-
[3.2.0]heptan-7-one 24 to be isolated as a single diastereoisomer. The X-ray crystal structure of a
precursor, the triester, 22a, has been obtained.
Descrição
Palavras-chave
Heterocycles Diels-Alder
Contexto Educativo
Citação
Journal of the Chemical Society, Perkin Transactions 1, 20, 3005-3012, 1997.