Rearrangement of N-tert-Butanesulfinyl α-Halo Imines with Alkoxides to N-tert-Butanesulfinyl 2-Amino Acetals as Precursors of N-Protected and N-Unprotected α-Amino Carbonyl Compounds

Abstract

Reaction of N-tert-butanesulfinyl α-halo imines with alkoxides afforded new N-tert-butanesulfinyl 2-amino acetals in good to excellent yield. These N-tert-butanesulfinyl 2-amino acetals are convenient precursors for the TMSOTf-promoted synthesis of the corresponding N-protected α-amino aldehydes and ketones, as well as for the HCl-promoted synthesis of 2-amino acetal hydrochlorides and α-amino ketone and α-amino aldehyde hydrochlorides in high yield. Via this method, an asymmetric synthesis of (S)-cathinone hydrochloride (er 94:6) was achieved.