Stereocontrolled Access to (Z)-Heteroatom-Substituted Fluoroalkenes Through Fluorine-Directed, Hydrogen-Bond-Assisted Elimination.

A general method for the stereocontrolled synthesis of (Z)-1,2-heteroatom-substituted monofluoroethylenes is described. The reaction proceeds via the Michael addition of N-, P-, and S-centered nucleophiles to 1-fluorovinyl sulfonium ylide (Ylide-VF) under mild conditions, followed by an E2 process. This general protocol exhibits broad functional group tolerance and significant application potential, as demonstrated by the late-stage functionalization of bioactive molecules and oligopeptides. Mechanistic investigations reveal that an intramolecular hydrogen bond within the Michael addition intermediate is the key stereocontrolling element, dictating the observed Z-selectivity.