Addition of lithium ethyl fluoroacetate to cis and trans α,β-epoxyaldehydes. Access to C2 fluorinated butyrolactones

The aldolisation reaction of lithium ethyl fluoroacetate with cis and trans α,β-epoxyaldehydes in their racemic forms proceeds with good C₃-OH diastereoselectivity and much less at the C₂-F carbon atom. A two-step reaction on the major aldol compounds (iodination, lactonisation) led to racemic functionalised C₂ fluorinated lactones, possessing a C₂/C₃cis relationship between the fluorine and hydroxyl groups.