Organocerium Additions to Chiral α,α-Dialkoxy Hydrazones: Asymmetric Synthesis ofN-Protected α-Amino Acetals and α-Amino Aldehydes

Abstract

A general and selective procedure for the diastereoselective additions of organocerium reagents to chiral α,α-dialkoxy hydrazones has been developed. The best reagent combination involved a 6:1 composition of RMet to CeCl3. Excellent yields and high selectivities were obtained after trapping as the iso-butyl carbamates. Lithiumammonia cleavage of the N-N bond followed by hydrolysis with TMSI afforded the protected α-amino aldehydes.