Nickel-Catalyzed Cross-Electrophile Coupling of Alkyl Fluorides: Stereospecific Synthesis of Vinylcyclopropanes

The stereospecific reductive cross-electrophile
coupling reaction
of 2-vinyl-4-halotetra­hydropyrans for vinylcyclopropane synthesis
is reported. The nickel-catalyzed reaction occurs with both alkyl
fluorides and alkyl chlorides. To the best of our knowledge, this
is the first reported cross-electrophile coupling reaction of an alkyl
fluoride. Ring contraction proceeds with high stereospecificity, providing
selective synthesis of either diastereomer of di- and trisubstituted
cyclopropanes. The utility of this methodology is demonstrated by
several synthetic applications including the synthesis of the natural
product dictyopterene A. 2-Vinyl-4-fluorotetra­hydro­furans
also undergo stereospecific ring contractions, providing access to
synthetically useful hydroxymethyl cyclopropanes.