Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The cyclization of hydroxamate unexpectedly afforded two isomeric β-lactams and . The mechanism for the formation of has been shown by carbon-13 labeling to involve a novel 1,2-acyl migration-cyclization process. ... The conversion of to has been shown by carbon-13 ...