A new method for the synthesis of (S)-α-methylisoserine and its incorporation into peptides

Article abstract of DOI:10.1055/s-1996-4387

(S)-(+)-Citramalic acid is converted into isocyanate 4 using hexafluoroacetone as the protecting agent. Isocyanate 4 represents a doubly activated species, which upon reaction with alcohols provides N-protected, carboxyl-activated α-methylisoserine derivatives, perfectly suited for peptide synthesis (5 → 8). Acylation of 4 with N-protected amino acids gives fully protected carboxyl-activated dipeptides. Ring opening with amino acid esters results in the formation of tripeptides (9 → 10).