Gadolinium triflate catalyzed alkylation of pyrroles: efficient synthesis of 3-oxo-2,3-dihydro-1H-pyrrolizine derivatives

Novel 2-alkylated pyrrole derivatives were synthesized regioselectively by Gd(OTf)3 catalyzed addition reactions of pyrrole to substituted dimethyl 2-benzylidenemalonate derivatives under mild reaction conditions. 2-Alkylated pyrrole derivatives are used for the construction of the 3-oxo pyrrolizine skeleton. Intramolecular cyclization of alkylated pyrrole derivatives afforded new diastereoselective 3-oxo-2,3-dihydro-1H-pyrrolizine derivatives with good to high yields.