Unusual [4+2]-Cycloaddition Reaction between Electron-Poor 1,2-Diaza-1,3-dienes and Electron-Poor Alkenes: Useful Entry to Novel Tetrahydropyridazines.

1,2-Diaza-1,3-dienes react with electron-poor alkenes to give the corresponding tetrahydropyridazines with high regio- and stereoselectivity. Both regio- and stereoselectivity can be explained considering the interaction between the LUMO of the 1,2-diaza- 1,3-diene and HOMO-1 of the alkene. [ABSTRACT FROM AUTHOR]