Synthesis and reduction of α-amino ketones derived from leucine

New α-amino ketones (5) derived from leucine have been synthesized by reaction of organometallics on N-methoxy-N-methylamide (4). The stereoselectivity of reduction of the α-amino ketones (5) was studied. The stereochemistry of the resulting α-amino alcohols (6) was established by transforming them into the oxazolidinones (8) by means of a new procedure.