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Chem."],"accepted":{"date-parts":[[2021,9,29]]},"abstract":"<jats:p>A wide range of <jats:italic>N<\/jats:italic>-(ethoxycarbonylmethyl)enaminones, prepared by the Eschenmoser sulfide contraction between <jats:italic>N<\/jats:italic>-(ethoxycarbonylmethyl)pyrrolidine-2-thione and various bromomethyl aryl and heteroaryl ketones, underwent cyclization in the presence of silica gel to give ethyl 6-(hetero)aryl-2,3-dihydro-1<jats:italic>H<\/jats:italic>-pyrrolizine-5-carboxylates within minutes upon microwave heating in xylene at 150 \u00b0C. Instead of functioning as a nucleophile, the enaminone acted as an electrophile at its carbonyl group during the cyclization. Yields of the bicyclic products were generally above 75%. The analogous microwave-assisted reaction to produce ethyl 2-aryl-5,6,7,8-tetrahydroindolizine-3-carboxylates from (<jats:italic>E<\/jats:italic>)-ethyl 2-[2-(2-oxo-2-arylethylidene)piperidin-1-yl]acetates failed in nonpolar solvents, but occurred in ethanol at lower temperature and microwave power, although requiring much longer time. 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