An unexpected elimination product leads to 4-alkyl-4-deoxy-4-epi-sialic acid derivatives

Abstract: A useful, unexpected β,γ-unsaturated-α-keto ester (ethyl (E)-5-acetamido-3,4,5- trideoxy6,7:8,9-di-OisopropylideneD-manno-non-3-en-2-ulosonate 5) was isolated in 91% yield following ozonolysis and chromatographic purification of its enoate ester precursor ethyl 5-acetamido-2,3,4, 5-tetradeoxy-6,7:8,9-di-O-isopropylidene-2methylene 4-nitro-D-glycero-D-galacto-nononate (6). [...]