Catalytic Asymmetric Construction of β-Amino Acid Precursors and Their Use in an Iterative Method Towards β-Peptide Synthesis

Towards the goal of novel β-peptide synthesis, a method to access a variety of enantioenriched β-amino acid precursors was developed. These β-amino acid precursors were then utilized in the synthesis of numerous β-peptides in solution and on solid support. The β-amino acid precursors allowing this unique technology are thiazinone and β-lactam heterocycles which were accessed via asymmetric cycloadditions of N-acyl imines and ketenes utilizing cinchona alkaloid catalysts. The methodology developed herein provides access to unique and previously unavailable β-amino acids and β-peptides