Remote Fluorination of α,β‐Unsaturated Carbonyls via Silyl Dienol Ethers

We report a general, regioselective, and metal free γ‐fluorination of α,β‐unsaturated carbonyls via silyl dienol ethers that are readily prepared from simple ketones and aldehydes. The transformation displays broad scope including 27 cyclic and acyclic siloxydienes providing γ‐fluoro compounds in 28–91 % yield. Notably, the reported conditions are also suitable for the synthesis of challenging tertiary fluorides. The regioselectivity of the reaction was studied on a series of acyclic siloxydienes and was observed to be sensitive to the conformational flexibility of the substrate. Diversification of the γ‐fluorocarbonyls demonstrates the promise of fluorine as a stereocontrol element.