Synthetic methods. 15. Unsaturated Acyl Derivatives of Silicon, Germanium, and Tin From Metalated Enol Ethers

The preparation of 1-lithio derivatives of some conjugated vinyl ethers is described. Reaction of these compounds with the chlorotrimethyl derivatives of silicon, germanium, and tin gives the corresponding metallovinyl ethers in 50-80% yield. At least in the case of silicon these reactions proceed with retention of stereochemistry. The silyl compounds undergo Z ↔ E photoisomerization. Hydrolysis of the ethers in aqueous acetone gives the corresponding acylmetallanes in 60-75% yield. The metalation and hydrolysis reactions are examined in some detail. The spectral properties of these novel unsaturated acylmetallanes are presented and discussed.