DIASTEREOSELECTIVE ADDITION OF ORGANOMETALLIC REAGENTS TO NOR-EPHEDRINE-DERIVED 2-ACYL-N-TOSYL-OXAZOLDINES

Addition of carbanionic reagents to the 2-acyl-N-tosyl-oxazolidines 1 and 11 has been studied. Organolithium and organomagnesium reagents add to the methyl ketone I with remarkable Re and Si pi-face selectivity respectively. With phenyl ketone 11 only organomagnesium reagents follow the above trend. Models accounting for the observed stereochemical behavior are proposed.