The sulfonamide moiety was introduced as a potential transition state isostere of the hydrolysis of the amide bond. Subsequently, the increased acidity of a sulfonamide N-H as compared to a regular amide N-H was explored in the development of peptidosulfonamide synthetic receptor molecules for binding and catalysis. The required building blocks for these compounds were accessible via an efficient synthesis, which also enabled the synthesis of oligopeptidosulfonamides as well as peptidosulfonamide-betapeptide hybrids. The structural consequences of the introduction of the peptidosulfonamide residues were studied and were further explored by the synthesis of cyclic peptidosulfonamides e.g. by ring-closing metathesis.