SYNTHESIS OF ORTHOGONALLY PROTECTED ACTINOIDIC ACID TRIMETHYL ETHER

We describe the asymmetric synthesis of actinoidic acid trimethyl ether with orthogonal protecting groups on the respective amino and carboxyl groups. The Stille biaryl coupling reaction of suitably functionalized aryl bromide and (trimethylstannyl)benzaldehyde gave the key intermediate biaryl aldehyde. Synthesis was accomplished by applying the asymmetric Strecker reaction to this aldehyde, followed by selectively removing the chiral auxiliary. By comparing its H-1-NMR spectra with those obtained from vancomycin, the stereochemistry of the synthesized diastereoisomer of actinoidic acid trimethyl ether was confirmed as an atropisomer of the (alpha S,alpha'R)-isomer.