Asymmetric hydrocyanation of aldehydes with cyclo-dipeptides: A new mechanistic approach

Article abstract of DOI:10.1016/0957-4166(96)00089-4

A new mechanistic suggestion for the asymmetric hydrocyanation reaction of aldehydes with cyclo[-(S)-phenylalanyl-(S)-histidyl] (CPH) as catalyst is presented. Kinetic measurements indicate a second order reaction in the cyclopeptide catalyst. A heterogeneous hydrogen bonded polymer of CPH is considered to be the reactive state of the catalyst where two adjacent imidazole bases function as the reactive sites. This structural proposition is also supported by MNDO calculations performed on a dimer of CPH.