Novel Synthesis of 4-Carboxymethyl 5-Alkyl/Aryl Oxazolidin-2-ones by Rearrangement of 2-Carboxymethyl 3-Alkyl/Aryl N - tert -Butoxycarbonyl Aziridines

A two-step approach for the diastereoselective synthesis of 4-carboxymethyl 5-alkyl/aryl oxazolidin-2-ones is described, which proceeds via the intermediate formation of 2-carboxymethyl 3-alkyl/aryl N - tert -butoxycarbonyl ( N -Boc) aziridines. By reaction of N -Boc β-amino methyl esters with LiHMDS and iodine, trans 2,3-disubstituted N -Boc aziridines are obtained with high stereoselectivities and yields. The final rearrangement to oxazolidin-2-ones is achieved by treatment with a catalytic amount of a Lewis acid and proceeds with high yield and complete regio- and stereoselectivity.