Macrocycles are among the most promising compounds pursued by the pharmaceutical industry. The combination of a (N-isocyanoimino) phosphorane, an aldehyde, and a linear peptide produces cyclic peptides containing 1,3,4,-oxadiazole moieties, imbedded within the peptide backbone, in a single step. The proprietary process involves connecting the ends of a linear peptide chain and simultaneously introducing an oxadiazole (ODZ) ring at the point of suture resulting in the so-called “ODZ macrocycles”. The oxadiazole ring is well regarded for its ability to mimic peptide bonds, yet impart superior drug-like properties to the corresponding molecules. This invention is a method that facilitates the rapid assembly of structurally and functionally diverse therapeutically relevant cyclic compounds by “depeptidizing” lead molecules and bestowing upon them the key attributes of medicinally relevant heterocycles.