Natural peptide sequences ligate to dirhodium centers through two bridging aspartate side chains, creating a macromolecular ligand framework with helical structure. The generation of a small peptide library allowed optimization of peptide sequence and produced an efficient catalyst for enantioselective carbenoid insertion into Si-H bonds. Analysis of the library indicates that the i-1 and i+3 positions of nonapeptides have the most significant effect on enantioselectivity, though the structural basis for selectivity is different at each of the positions.

Searching with a beady eye: A high-throughput, on-bead screen of rhodium metallopeptide catalysts was developed in a 96-well format for asymmetric cyclopropanation. Different sequences of natural L-amino acids have been identified that produce opposite product enantiomers. In addition to styrene derivatives, high enantioselectivity is observed for vinyl ether and vinyl amine derivatives.

A tridentate eq-eq-ax peptide ligand for rhodium(ii) complexes, discovered by high-throughput on-bead screening, is an efficient and selective catalyst for asymmetric cyclopropanation reactions.

Rhodium(II) metallopeptides display useful secondary structure, self-assembly, and catalytic activity. The bis-peptide complexes exhibit subtle orientational isomerism that affects function, but is challenging to characterize. We report that pyrene excimer fluorescence measurements provide a conclusive proof of isomeric structure.

Dirhodium metallopeptides have been developed as selective catalysts for asymmetric cyclopropanation reactions. A selective ligand sequence has been identified by screening on-bead metallopeptide libraries in a 96-well plate format. Efficient ligand synthesis and screening allows a 200-member library to be created and assayed in less than three weeks. These metallopeptides catalyze efficient cyclopropanation of aryldiazoacetates, providing asymmetric access to cyclopropane products in high diastereoselectivity.