Chapter 5 Generation of Alkylideneallyl Cations from Alkylidenecyclopropanone Acetals: Selectivity of Reaction with Nucleophiles

摘要

Ring opening reaction of alkylidenecyclopropanone acetals readily proceeds in the presence of Lewis or Bransted acids to produce 1-alkylidene-2-oxyallyl cation, which is provided for the reaction with nucleophiles such as chloride, alcohols, siloxyalkenes, and furans. The reaction of this cation with the carbon nucleophiles gives products of [4 + 3] and [3 + 2] cycloaddition as well as those of nucleophilic addition. The modes of addition reactions are controlled by the oxy group of the cation and by the reaction conditions including solvent.