1: With iron; zinc(II) iodide; zinc; CoBr2{N-[(pyridin-2-yl)methylene]methanesulfonamide} in dichloromethane T=20°C; Diels-Alder reaction; 24 h; 2: With 2,3-dicyano-5,6-dichloro-p-benzoquinone in benzene T=20°C;

[Rh(1,5-cyclooctadiene)(1,4-bis(diphenylphosphino)butane)]PF6 in dichloromethane T=25°C; 168 h; in a sealed tube under argon atmosphere; Yield given. Further byproducts given. Yields of byproduct given;