Herstellung von steroisomeren 3-Sulfinylbuttersäuren aus (R)- und (S)-4-Methyl-2-oxetanon

Summary

The β-lactone ((S) and (R)-4-methyl-2-oxetanone,1 , ent-1), readily available from (R)- and (S)-3-hydroxybutyric acid, is opened by sodium hydrosulfide, sodium alkane- and arenethiolates, respectively, with inversion of configuration. The resulting 3-(alkylthio)-2f, 2g, and 3-(arylthio)butyric acids, 2b-2e, ent-2h-2k (Table 1), oxidized with hydrogen peroxide in acetone to give the corresponding 3-(alkylsulfinyl)- and 3-(arylsulfinyl)butyric acids as mixtures of diastereoisomers3b-3k and 4b-4k. These are separated and the purelike and unlike diastereoisomers isolated and fully characterized (Table 4). Configurational assignments rest upon a crystal structure analysis (Figure 1) and comparison of properties in the two series.