Palladium-catalysed regio- and stereo-controlled C-2 β-fluorovinylation of indoles†

Vinyl-fluorides appended to heterocycles are a broadly underdeveloped family of functionality with potential application in bioactive compounds. Herein, we disclose a C–H functionalisation strategy for the regio- and stereo-controlled synthesis of Z-β-fluorovinyl indoles exclusively in the C-2 position. Z-Fluorovinyl iodonium salts, which are formed from alkynes through a Ag-catalysed process, engage in a palladium-catalysed C-2 C–H functionalisation of indoles (and pyrroles) to achieve a broad scope of β-fluorovinyl heterocycles in good to excellent yields. Mechanistic studies and product derivatisations are provided.