Process for the preparation of halogenated alpha-amino-ketones and alpha-amino-alcohols

摘要

Prodn. of halogenated alpha -amino ketones or alcohols of formula (I) comprises: (a) reacting an amino acid ester of formula (II) with a lower alkyl-lithium cpd. and a silyl chloride of formula ClSiR4R5R6 (IV) to form a silyl protected deriv. of formula (III); (b) reacting (III) with a dihalomethane and a lower alkyl-lithium to give a ketone of formula (I; Q = CO); and opt. (c) reducing the ketone to an alcohol of formula (I; Q = CHOH): X = halogen; Q = CO or CHOH; R1 = amino protecting gp.; R2 = H or an amino acid side chain; R3 = lower alkyl; R4-R6 = lower alkyl or phenyl.