De Kimpe, Norbert Synthesis of 4,4-Disubstituted beta-Lactams by Regiospecific Electrophile- and Silver-Induced Ring Expansion of 2,2-Disubstituted 1-Methoxycyclopropylamines. [electronic resource] - The Journal of organic chemistry Sep 1996 - 6500-6503 p. digital Publication Type: Journal Article ISSN: 1520-6904 Standard No.: 10.1021/jo960296k doi