Investigations of a Nucleophilic Alaninol Synthon Derived from Serine

A nucleophilic synthon, ( S )-(+)-4-(2-oxazolidonyl)-methyltriphenylphosphinyl iodide 6, available from l -serine in five steps (overall yield of 52%), reacts with aldehydes to produce alkenes in good to excellent yields (74−89%) and, in some cases, provides excellent stereocontrol of the new double bond. The geometry of the newly formed double bond is influenced by the nature of the aldehyde and reaction conditions. The trends in olefin configuration are discussed. Application of this methodology allows for easy preparation of molecules containing double bonds allylic to nitrogen, including oxazolidinones and β,γ-unsaturated amino alcohols. Several of the unsaturated oxazolidinones are converted to β,γ-unsaturated amino alcohols in high yields (75 to 90%).