AbstractThe electrochemical reductive silylation of N-alkoxyphthalimides leads to 2-alkoxy-1,3-bis- (trimethylsilyloxy)-isoindoles, which can be trapped by cycloaddition reactions with dienophiles like methyl acrylate and dimethyl acetylenic dicarboxylate. The unstable primary cycloadducts form naphthoquinones and dihydronaphthoquinones as monoxime derivatives. All oximes form syn and anti isomers.