| abstract |
A process comprising substitution of an acceptor molecule comprising a group —XC(O)— wherein X is O, S, or NR 8 , where R 8 is C 1-6 alkyl, C 6-12 aryl or hydrogen, with a nucleophile, wherein the acceptor molecule is cyclised such that said nucleophilic substitution at —XC(O)— occurs without racemization, is provided. This process has particular application for the production of a peptide by extension from the activated carboxy-terminus of an acyl amino acid residue without epimerization. |