Trimellitic anhydride was attached to Merrifield resin and a ketene was generated from polymer-bound phthaloylglycine. Then this polymer reacted with imines in the presence of Vilsmeier reagent and triethylamine to afford the solid-phase-tethered β-lactam products. Selective cleavage of supported β-lactams by trifluoroacetic acid and methylhydrazine gave 4-carboxyphthalimido-and 3-amino-β-lactams, respectively. The trans-stereochemistry ...