Diimine Reduction of C=C Double Bonds: Scope and Limitations of the Application to Solid-Phase Peptide Synthesis

Experiments have been performed to prove the applicability and efficacy of 2-nitrobenzenesulfonobydrazide in the on-resin reduction of C=C double bonds of peptide derivatives. The method is useful for the two solid-phase peptide synthesis strategies, Fmoc/tBu and Boc/Bz, which is compatible with common protecting groups and, in some instances, with other functionalities of interest in the preparation of highly elaborated peptide derivatives/peptidomimetics. The utility of the method has been demonstrated by the clean reduction of a C=C-bridged 11-mer cyclic peptide derivative to its hydrocarbon C-C analogue. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)