Synthesis and Spectroscopic Characterization of ß-Di-, ß-Tri-, and ß-Hexapeptides Built with (S)-2-Methylene-3-aminoalkanoic Acids Derived from Alanine, Valine, and Leucine

Methylthiomethylation and subsequent sulfoxidation and pyrolysis of the N-Boc-protected ß3-amino acid methyl esters derived from Ala, Val, and Leu provided the a-methylene esters; these were then used to synthesize the ß-peptides specified in the title (step-by-step and fragment coupling in solution). The novel ß-peptides were fully characterized, but neither solid-state nor solution structures were found.