Diastereoselective additions of organolithium reagents to the C=N bond of protected erythrulose oxime ethers. Synthesis of enantiopure α,α-disubstituted α-aminoacids

Article abstract of DOI:10.1016/S0040-4039(97)00165-2

The addition of organolithium reagents to the C=N bond of several erythrulose-derived chiral (E)- and (Z)-ketoxime ethers has been shown to be highly diastereoselective for the (E)-isomers. A chelated transition state has been proposed to explain this result. The addition products were converted into the two α,α-disubstituted α-aminoacids (R)-2-(-)-methylserine and (R)-(+)-2-phenylserine.