Stereoselective synthesis of spirocyclic nitronates by SnCl4-promoted reaction of nitroalkenes with C-2 substituted 4-methylidene-1,3-dioxolane

SnCl₄-promoted [4 + 2] cycloaddition of β-nitrostyrenes to 4-methylidene-1,3-dioxolane provides stereoselective synthesis of spirocyclic nitronates. 2-Nitrovinyl benzoate under the same conditions produces δ-substituted nitrodiene as a single E,E-isomer.