Cycloaddition Reactions of Benzonorbornadiene and Homonorbornadiene: New Isoxazoline and Pyridazine Derivatives

Ten new isoxazoline derivatives were synthesized from the reactions of benzonorbornadiene and homonorbornadiene derivatives with nitrile oxides formed from benzaldehyde and 4‐substituted benzaldehyde. Two new pyridazine derivatives were also synthesized from the reaction of the homonorbornadiene derivatives with 3,6‐di (2‐pyridyl)‐s‐tetrazine. It was seen that all cycloaddition reactions were realized as exo selectivity. Finally, γ‐Gauche effect in the isoxazoline derivatives was discussed.