Reduction of Polysilacycloallenes by Sodium:  Structure of the Donor-Free Sodium Salt of an Allyl Anion

The reduction of the tetrasilacyclohepta-1,2-diene 1 afforded the stable allyl anion 2. The structure of 2 (Na salt) was determined by a single-crystal X-ray diffraction analysis. The reaction of allyl anion 2 with methyl iodide gave the methyl adducts 3a,b.