Synthesis of bis-peptides attached on poly[n]norbornene molecular scaffolds with well-defined relative positions and distances

This article describes novel synthetic approaches to polynorbornene molecular scaffolds substituted with peptides at various, well-defined positions. A library of norbornene building blocks with attached peptides was prepared. Alkene cyclobutane epoxide (ACE) coupling method was used as a key step reaction for the connection of two norbornene building blocks into bis-peptide scaffolds. Photodimerization of cyclobutene diesters offers an alternative route to polynorbornene bis-peptides. Pyrrolo-peptides were used for preparation of peptide-substituted 7-aza norbornenes. Asymmetrical bis-peptide scaffolds were prepared by ACE coupling of peptide-norbornane epoxide with another norbornene-peptide block. Chemical elaboration of bridgehead dimethyl esters of ACE products or epoxide ACE reagents was also used for peptide attachment.