Transamidation chemistry in which amine exchange is performed on the amide bond by transamidase enzymes, such as sortase and transglutaminase, has significant biological importance and potential for environmentally benign synthesis. A thermodynamically neutral transformation of an intrinsically stable poor electrophile, transamidation has also been achieved on ordinary amides under ambient conditions through the employment of transition metal catalysis and under strongly basic conditions. In the context of Nto C-direction synthesis, polyamide mixtures were prepared under so claimed "prebiotic conditions" in which N-acetamido amides were heated with amino amides in 0.5 M NaOH at 80 °C. Moreover, peptides have been synthesized by ring-opening of N-alkyl N-Boc-diketopiperazines without epimerization on heating with amino esters in the neat and with peptide esters in toluene with a benzoic acid catalyst. In addition, a number of methods have been conceived for performing overall transamidation chemistry by way of thioester intermediates in native chemical ligation strategies towards peptide products. Scheme 11. N-to C-Direction synthesis by way of N-alkyl N-acylsulfonamide