Cycloaddition de derives organiques insatures du silicium,du germanium et de l'etain

The effect of atom M and of its substituents Σ upon dienophilic activity of Σ₃MCHCH₂ and Σ₃MCCH (MC, Si, Ge, Sn) is interpreted in terms of a perturbation scheme involving the lowest unoccupied orbital of the dienophile and the highest occupied orbital of the diene. This scheme also explains the stereochemistry of Diels-Alder reactions and the regioselectivity of the ene reaction with organometallic compounds.