Synthesis of oxazolidinones and 1,2-diamines from N-alkyl aziridines

Reactions of N-alkyl-substituted aziridines with LiI followed by an electrophile are discussed. In the first series of reactions, the electrophile is carbon dioxide and the product is an oxazolidinone. In all cases, either no reaction occurred or a high yield of product was obtained. HMPA had to be added to some reactions to dramatically improve the regiochemistry. Net retention of stereochemistry was observed. In the second series of reactions, the electrophile is an iminium salt and the product is a 1,2-diamine. Here the reaction is highly regioselective in THF without the addition of HMPA. Unlike the oxazolidinone chemistry, the diamine formation works equally well with or without the addition of LiI. With respect to the regiochemistry, the results are the same with and without added LiI. However, with respect to the stereochemistry, in the presence of added LiI, the reaction with the iminium salt goes with net retention of stereochemistry. In contrast, with no added Lit, in some cases the reaction goes with net retention and in some cases with net inversion of stereochemistry.