The preparation of (S)-Aspartate semi-aldehyde appropriate for use in biochemical studies

We report two three-step syntheses of (S)-aspartate semi-aldehyde, an important synthetic and biosynthetic precursor, from diprotected aspartic acid. The first synthesis proceeds via a thioester, the second via a Weinreb amide. Each route yields pure (S)-aspartate semi-aldehyde in excellent yield. (S)-Aspartate semi-aldehyde prepared in this manner has proved appropriate as a substrate for detailed enzyme studies.