Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA Manuscript received 3 October 1997 A variety of substituted ��-lactams which serve as intermediates for diverse natural products have been prepared by rapid microwave assisted synthesis. Indium mediated reactions in aqueous media with azetidin-2,3-dione have been conducted in high yield to provide intermediates for pyrrolidine and piperidine alkaloids. The synthetic approaches reported here are more ecologically friendly than parallel conventional reactions described in the literature.