A NaCl-mediated electrochemical oxidation of amino acid carbamates (R1 = Boc, Cbz) afforded α-methoxylated α-amino acids. Subsequent acid-catalyzed elimination delivered valuable dehydroaminoacidderivatives. The simplicity of our setup using graphite-electrodes was showcased, producing N-Boc-ΔAla-OMe on a decagram scale.
The fully protected derivatives of the diamino acids lysine and ornithine (n=1, 2) can be oxidized selectively in the sidechain using a Mn(OAc)2/peracetic acid/NaOAc system. The ε or γ carbon, respectively, is converted to the aldehyde oxidation state, protected as the cyclic N,N-acetal.