Patent ID: 6974876

Claim:
A method of preparing a mixture of alpha-amino epoxide diastereomers or the pharmaceutically acceptable salts, esters, or amides thereof, said method comprising treating, under epoxidation conditions, a protected chiral aminoaldehyde having the chemical formula: with a halo-substituted organometallic methylene-adding reagent to yield said mixture comprising a first diastereomer having the chemical formula: and a second diastereomer having the chemical formula: wherein said first diastereomer is present in an amount of at least about 85% by weight of said mixture, wherein P 1 and P 2 are radicals independently selected from the group consisting of acyl, aralkyl, alkenyl, silyl, aralkoxycarbonyl, alkoxycarbonyl, cycloalkenylalkyl, and allyl, or P 1 and P 2 together with the nitrogen atom to which they are bonded form a heterocyclic ring; wherein P 1 and P 2 may be substituted at one or more substitutable positions with one or more substituents independently selected from halo, C 1 -C 8 alkyl, alkoxy, hydroxy, nitro, alkenyl, amino, alkylamino, acylamino, and acyl; wherein R 1 is a radical selected from the group consisting of alkyl, aryl, cycloalkyl, cycloalkylalkyl and aralkyl; and wherein R 1 may be substituted at one or more substitutable positions with one or more substituents selected from the group consisting of alkyl, halo, NO 2 , OR 9 and SR 9 , wherein R 9 is hydrogen or alkyl.