A General and Practical Synthesis of (R)-Phthalimido Aldehydes and D-α-Amino Acids from D-Mannitol

Article abstract of DOI:10.1021/jo00376a046

A short and practical synthesis of five D-α-amino acids is described from D-mannitol as the chiral educt.The key steps in the sequence are (a) the erythro-selective addition of organometals to (R)-2,3-O-isopropylideneglyceralaldehyde, (b) the Mitsunobu inversion substituting N-phthalimide for hydroxyl, and (c) acetonide hydrolysis and glycol cleavage to give the N -phthaloyl-(R)-α-aminoaldehydes 7.These are oxidized under Jones conditions to give the N-protected amino acids 8.The examples investigated (alanine, aminobutyric acid, norvaline, and allyl- and vinylglycine) demonstrate the general applicability of the method.