Iodide dealkylation of benzyl, PMB, PNB, and t-Butyl N-acyl amino acid esters via lithium ion coordination

Lithium iodide promotes ester dealkylation in compounds containing an amide carbonyl in the γ-position to the ester carbonyl, as is found in N-acyl amino acid esters. Activation of the ester carbonyl via lithium ion coordination is facilitated by aprotic non-polar solvents such as THF and EtOAc. This process is not limited to methyl esters but readily dealkylates benzyl, PMB, PNB, and t-butyl esters and is especially suitable for use with β-lactam esters because of the mild conditions.