Stereoselective One‐Pot Sequential Dehydrochlorination/ trans ‐Hydrofluorination Reaction of β‐Chloro‐α,β‐unsaturated Aldehydes or Ketones: Facile Access to ( Z )‐β‐Fluoro‐β‐arylenals/β‐Fluoro‐β‐arylenones

The monofluoroalkene substructure shows a high potential as a fluorinated synthon in organic synthesis. However, control of the Z / E stereoselectivity of multi‐substituted monofluoroalkene products in one‐pot reactions still remains a challenge. An unprecedented one‐pot approach for the highly regio‐ and stereoselective preparation of functionalized ( Z )‐β‐monofluoro tri‐substituted alkenes from readily available β‐chloro‐α,β‐unsaturated aldehydes or ketones has been explored. Mechanistic studies demonstrated that the reaction is initiated by dehydrochlorination of the substrates to give alkynyl aldehydes/ketones, followed by their trans ‐hydrofluorination. It is worth mentioning that a fluorinating reagent with suitable basicity and nucleophilicity plays a key role in promoting the formation of ( Z )‐β‐fluoro‐β‐aryl tri‐substituted monofluoroalkenes.