A process for production of cyclopropyl-fused pyrrolidine-based inhibitors of dipeptidyl peptidase IV is provided which employs a BOC-protected amine of the structureprepared by subjecting an acid of the structureto reduce amination by treating the acid with ammonium formate, nicotinamide adenine dinucleotide, dithiothreitol and partially purified phenylalanine dehydrogenase/formate dehydrogenase enzyme concentrate (PDH/FDH) and without isolating treating the resulting amine of the structure 2with di-tert-butyl dicarbonate to form the BOC-protected amine.
