A New Approach towards the Asymmetric Fluorination of Alkenes Using Anionic Phase-Transfer Catalysts

摘要

The addition of halogen electrophiles to the carbon-carbon double bond is one of the most common methods for the functionalization of alkenes. Chlorine, bromine, and iodine electrophiles react even with simple, nonactivated alkenes forming cyclic halonium intermediates which are subsequently opened by a suitable nucleophile. Electrophilic fluorination reagents are less reactive towards simple alkenes presumably because cyclic fluoronium ions are not formed. For this reason electrophilic fluorinations are usually conducted on more activated carbon-carbon double bonds like enol ethers or allyl silanes.