The unprecedented C-alkylation and tandem C-/O-alkylation of phenanthrolinium salts with cyclic 1,3-dicarbonyl compounds

N-p-Nitrobenzyl- or N-phenacylphenanthrolinium bromides reacted with a series of cyclic 1,3-dicarbonyl compounds in acetonitrile in the presence of triethylamine as base catalyst to give the unprecedented C-alkylated products and tandem alkylated/intramolecular O-alkylated oxazabicyclic compounds according to the structure of cyclic 1,3-dicarbonyl compounds.