Enantioselective Synthesis of Protected α-Hydroxy Aldehydes<i>via</i>Alkylation of Metalated Chiral Hydrazones

Abstract

α-Hydroxy aldehydes 4 bearing various protecting groups, such as the tert-butyldiphenylsilyl (TBDPS), the benzyloxymethyl (BOM) and the benzyl group, are prepared in high enantiomeric excess by azaenolate alkylation of protected α-hydroxy acetaldehyde hydrazones 2, novel synthetic equivalents of the α-hydroxy acetaldehyde d2-synthon.