D-Erythronolactone as a C-4 building unit .2. A short and efficient synthesis of both enantiomers of epi-muricatacin, a diastereoisomer of the native acetogenin from Annona muricata

Both enantiomers of epi-muricatacin (+)- and (-)-2 have been prepared from 2,3-O-isopropylidene-D-erythrose 7. The enantiomers (+)- and (-)-2 are obtained in good yields and with high diastereoisomeric and enantiomeric purity. The aim of the synthesis is to obtain both enantiomers of the target molecule from one chiral precursor. This was made possible by the reaction sequence for the introduction of the two different side chains being exchangeable.