Synthesis of Pyrroles with Fused Carbocycles or Heterocycles from Weinreb N-Vinyl-a-amino Amides Fused Pyrroles from Weinreb N-Vinyl-a-amino Amides

SYNTHESIS 2005, No. 18, pp 3152–3158xx.xx.2005 Advanced online publication: 06.10.2005 DOI: 10.1055/s-2005-916037; Art ID: Z09905SS © Georg Thieme Verlag Stuttgart · New York Abstract: Pyrroles fused to diverse carbocycles and heterocycles were prepared from Weinreb N-vinyl-a-amino carboxamides integrated in cyclic systems. The selective reaction of the carboxamide group with organometallic compounds allowed us to obtain a great variety of the carbonyl intermediates analogous to the Knorr synthesis, which were thermally cyclized. The principal limitation of the method was due to the insolubility of some metallic intermediates as well as to the low nucleophilicity and stability of the enamine during the cyclization process.