Reaction of alkyl, acetoxy, and silyl enol ethers of 3-(organosilyl)cyclohexanone with molecular dioxygen in toluene at 110 degrees C produced the corresponding conjugated enones in yields up to 88% yield. The reaction of the same type failed on replacement of the silyl group at the C-3 position with an isopropyl group. These results indicate the existence of an unprecedented silicon-induced ene-type reaction. Its reaction mechanism, generality, limitations, and exceptions are discussed.

Organo-silicon compounds S 0060Silicon-Induced Ene-Type Reaction in the Thermal Conversion of Enolates to β-Silyl Enones with Molecular Dioxygen. -An appropriately chosen C-3-silyl group is crucial for the reaction. The method is applied to cyclohexanones and other types of substrates such as bridged (XI), polycyclic (XIII) and hindered (VII) enol acetates. -(HWU*, J. R.; CHEN, C. H.; HSU, C.-I.; DAS, A. R.; LI, Y. C.; LIN, L. C.;