3 (R'= Boc) 30 min gave aldehyde 3,(R'= Boc), again in good yield. Little information is available regarding the chiral stability of such a-amino aldehyde derivatives. l'Therefore, we have analyzed the optical purity and stability of samples of the aldehyde 3 (R'= Boc) taken immediately from the oxidation and samples stored at 0" C and at ambient temperature. The aldehyde samples were reduced with sodium borohydride to carbinol 4 and then oxidized ...