Fluorine–copper exchange reaction of α,β,γ,γ,γ-pentafluorocrotonates with organocuprates: Generation and cross-coupling reactions of β-metallated α,γ,γ,γ-tetrafluorocrotonates

Reaction of α,β,γ,γ,γ-pentafluorocrotonates with organocuprates derived from organomagnesium or zinc reagents in THF at −78 °C for 1 h took place smoothly to generate β-metallated intermediate, of which hydrolysis gave the β-reduction product in good yield. The fluorinated vinylcopper intermediate formed by fluorine–copper exchange was found to be stable at low temperature due to the strong electron-withdrawing effect of a CF3 group, and was readily converted to various types of β-substituted products in good yields with high stereoselectivity by treating with electrophiles, such as iodine and allylic bromides.