Functionalisation of Unsaturated Amides: Synthesis of Chiral α- or β-Hydroxy Acids
Mercury cyclisation of hemiamidals containing a stereogenic centre affords diastereoisomeric mixtures of tetrahydro-1,3-oxazin-4-ones or oxazolidin-4-ones, which are easily separated by silica gel chromatography and hydrolysed to give chiral α- and β-hydroxy acids.