The absolute configuration of (2S,4S)and (2R,4R)-2-tert-butyl-4-methyl-3-(4-tolylsulfonyl)-1,3-oxazolidine-4-carbaldehyde

The title enantiomorphic compounds, C16H23NO4S, have been obtained in an enantiomerically pure form by crystallization from a diastereomeric mixture either of (2S,4S)- and (2R, 4S)or of (2R, 4R)- and (2S, 4R)-2-tert-butyl-4-methyl-3-(4-tolylsulfonyl)1,3- oxazolidine-4-carbaldehyde. These mixtures were prepared by an aziridination rearrangement process starting with ( S)- or ( R)-2-tert-butyl-5-methyl-4H- 1,3- dioxine. The crystal structures indicate an envelope conformation of the oxazolidine moiety for both compounds.