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 interm ediate formation of a carboxymethyl 3-alkyl/aryl N-tert-butoxycarbonyl (N-B oc) aziridines. By reaction of N-Boc p-amino methyl esters with LiHMDS and iodine, trans 2,3-disubstituted N-Boc aziridines are obtained with high ste reoselectivities and yields. The final rearrangement to oxazolidin-2-ones i s achieved by treatment with a catalytic amount of a Lewis acid and proceed s with high yield and complete regio and stereoselectivity.