Tandem 1,3-azaprotio cyclotransfer–cycloaddition reactions between aldoximes and divinyl ketone. The effect of oxime E/Z-isomerism on cycloaddition stereoselectivity

Abstract

The tandem 1,3-azaprotiocyclotransfer–cycloaddition reaction between aldoximes and divinyl ketone affords mixtures of exo- and endo-isomers of substituted 1-aza-8-oxabicyclo[3.2.1]octan-4-ones, the ratio of which is dependent on the E/Z geometry of the starting oxime and its ability to isomerise under the thermal reaction conditions.