Reduction of beta-enamino ketones 2 with NaBH4 in glacial acetic acid gave gamma-amino alcohols 1 in 70% to 98% yield with diastereomeric excesses, preferentially the syn product, from 44% to 90%. The stereochemistry of these compounds was confirmed by analysis of their tetrahydro-1,3-oxazine derivatives 3.
amino alcohols; enamino ketones; oxazines; stereoselective reduction