Diastereoselective additions of organolithium and organomagnesium reagents to the C=N bond of a chiral, cyclic nitrone derived from erythrulose

Article abstract of DOI:10.1016/S0040-4039(98)00400-6

The reaction of the 3,4-O-isopropylidene-L-(S)-erythrulose with hydroxylamine, followed by treatment of the resulting mixture of (E)- and (Z)-oximes with acetone and an acid catalyst, afforded two crystalline chiral compounds. Through X-ray diffraction analysis, these products were identified as a double acetonide derived from the (E)-oxime and a cyclic nitrone derived from the (Z)-oxime. The additions of organolithium and organomagnesium reagents to the C=N bond of the nitrone were found to be diastereoselective. The addition products are useful intermediates for the preparation of α,α- disubstituted α-aminoacids and other nitrogen-containing compounds in enantiopure form.