I. Synthesis of Hydroxy Cyclopropyl Peptide Isosteres using Chain Extension Cyclopropanation Reaction. II. Synthesis and Stereochemical Studies of the Phenylalanine Derived Bicyclic Lactones

Rekha Kumari Chhetri, University of New Hampshire, Durham


The zinc carbenoid-based methodology has been developed to modify amino acid residues into cyclopropyl-incorporated species which are synthetic precursors to a novel class of peptide isosteres referred to as hydroxycyclopropane isosteres. This methodology provides the unique opportunity to explore an unprecedented family of potential protease inhibitors. Formation of the cyclopropanols derived from phthalimide-protected L-phenylalanine was performed to understand the stereochemical preference of these reactions. Stereochemical assignment of cyclopropanols was performed using X-ray crystal structure data.

Use of zinc-mediated homologation-cyclization-rearrangement-lactonization (HCRL) reactions for the synthesis of bicyclic lactones from diprotected L-phenylalanine was studied. These lactones were further derivatized at the carbon adjacent to the cyclopropyl moiety to study the stereochemical preference of the alkylation reaction. Studies to understand the role of chiral auxillary were performed.