Non‐Ionic Peterson‐type Olefination Reactivity and its Use in a Silicon‐promoted Carbonyl‐Carbonyl Cross Coupling Reaction

The [2+2] cycloaddition reaction between the Si=C double bond of adamantylsilene and the carbonyl group of aliphatic, aromatic or acetylenic ketones and aldehydes is demonstrated. The product of this reaction that is central to a non‐ionic version of the Peterson olefination is an unusual four‐membered 1,2‐silaoxetane heterocycle that was characterized spectroscopically and crystallographically. In the presence of SiO 2 , the silaoxetane undergoes retro‐cycloaddition with the formation of alkene products. As the [2+2] cycloaddition proceeds without the necessity of any base, enolizable ketones can be converted into olefins. In addition, it is shown that the adamantylsilene can be produced in situ by a sila‐Peterson reaction, providing valuable input for the development of a new one‐pot silicon‐based reductive carbonyl‐carbonyl cross coupling methodology.