Solid-Phase Synthesis of Monocyclic β-Lactam Derivatives

Liquid-phase studies concerning the solid-phase synthesis of monocyclic β-lactams via the ester-enolate imine condensation route have been conducted utilizing triazene esters 1 and 2 as model compounds. Esters were attached to benzylamine resin 6 by a triazene linker employing the respective diazonium salts. Immobilized ester-enolates 8 and 10 were reacted with various imines and imine precursors to give polymer-bound β-lactams 14 and 17 in different substitution patterns. Traceless cleavage from the triazene linker yields the desired β-lactams 16 and 19.