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N-Bridgehead pyrroles are efficiently prepared from cyclic secondary vinylogous carbamates using a two-step sequence. This sequence involves C-propargylation followed by a silver-catalyzed intramolecular hydroamination. Hydroamination is brought about using microwave irradiation

An Expeditious Synthetic Access to b-(Z)-[(1-Propynyl)amino]enones and b-[(Z)-(1-Propynyl)amino]enoates A n E x p e d i t i o u s S y n t h e t i c A c c e s s t o β -( Z ) -[ ( 1 -P r o p y n y l ) a m i n o ] e n o n e s a n d E n o a t e s Abstract: The silver nitrate promoted reaction of propargyl bromide with (Z)-4-amino-3-penten-2-ones and (Z)-3-amino-2butenoates provides rapid access to β-(Z)-[(1-propynyl)amino]enones and β-[(Z)-(1-propynyl)amino]enoates respectively.

Silver-Catalyzed Hydroamination: Synthesis of Functionalized Pyrroles. -A sequence including base-promoted propargylation of secondary enaminones followed by silver-catalyzed intramolecular hydroamination allows the synthesis of highly substituted pyrroles (IV). -(ROBINSON, R. S.; DOVEY*, M. C.; GRAVESTOCK, D.; Tetrahedron Lett. 45 (2004) 36, 6787-6789; Warren Res. Lab., Sch. Chem., Univ. KwaZulu-Natal, Scottsville 3209, S. Afr.; Eng.) -Mais 51-089

Pyrrole derivatives R 0120Silver-Catalyzed Hydroamination: Synthesis of N-Bridgehead Pyrroles, Incorporating a Protection-Deprotection Strategy for Preparation of Cyclic Secondary Vinylogous Carbamates. -A mild and efficient method for the preparation of secondary cyclic vinylogous carbamates (IV) using Eschenmoser sulfide contraction is developed. The products are rapidly converted into the corresponding N-bridgehead pyrroles (VII) using a two-step sequence. It involves C-propargylation followed by a silver-catalyzed intramolecular microwave-assisted hydroamination. The procedure shows an improvement in overall yields compared to the one-pot approach with the added bonus that the hydroamination is catalytic with respect to silver(I) whereas the one-pot procedure requires a stoichiometric equivalent. -(ROBINSON, R. S.; DOVEY*, M. C.; GRAVESTOCK, D.; Eur. J. Org. Chem. 2005, 3, 505-511; Warren Res. Lab., Sch. Chem., Univ. KwaZulu-Natal, Scottsville 3209, S. Afr.; Eng.) -Bartels 22-106