Synthesis of N-Protected L-DOPA(acetonide) Derivatives

The modular synthesis of N-protected L-DOPA(acetonide) derivatives from readily available H-L-DOPA-OH is reported. A consecutive protecting group strategy and a partial hydrogenolytic removal affords H-L-DOPA(acetonide)-OH as key intermediate. Subsequent N-protection provides Fmoc-, Boc-, Cbz-, and Alloc-protected derivatives in excellent yields (95–99%). The key intermediate was further converted into the corresponding N-carboxyanhydride – a building block for polypeptide synthesis.