Nouveaux intermediaires du germanium π-lie: les germaphosphimines

The formation of new π-bonded germanium intermediates with dicoordinated phosphorus atoms, germaphosphimines [R 2 2GePR′], has been observed in the exchange reaction between 2,5-disilaphospholanes and dialkyldihalogenogermanes. These transient species have been clearly characterized by insertion and ring expansion reactions on ethylene oxide and sulfide with formation of new heterocycles 2-germa-3-oxyphospholanes and 2-germa-3-thiophospholanes.