Influence du silicium et du germanium sur l'ene-reaction-comportement inattendu des allenylsilanes

The determining role of silicon and germanium for ene syntheses was confirmed in the reactions between 1-sila and 1-germacyclopent-3 enes or allenylsilanes and PhSO₂NSO, a highly reactive new enophile. In the case of the cyclic enes the reaction led to new α,β-unsaturated β-functional cyclic derivatives which can be easily reduced into the corresponding thiols. With allenylsilanes, the adducts resulting from the ene-reaction with PhSO₂NSO or 4-phenyl 1,2,4-triazoline 3,5-dione have an acetylene structure whereas the substituted allenes usually give conjugated diene derivatives.