Philip Charles Levett

Tandem 1,3-azaprotio cyclotransfer-cycloaddition reactions between ketoximes and divinyl ketone or its equivalents: Lewis acid mediated rate enhancement and control of cycloaddition regioselectivity

Abstract The tandem 1,3-azaprotio cyclotransfer-cycloaddition reaction between a ketoxime and divinyl ketone or its equivalents [2-chloroethyl vinyl ketone and bis(2-chloroethyl) ketone] affords high yields of substituted 1-aza-7-oxabicyclo[3.2.1]octan-4-ones and 1-aza-8-oxabicylo[3.2.1]octan-4-ones. Addition of zinc bromide results both in rate enhancement and control of cycloaddition regioselectivity affording almost exclusively 1-aza-7-oxabicyclo[3.2.1]octan-4-ones.