Stereospecific Synthesis of Fluoroalkenes by Silver-Mediated Fluorination of Functionalized Alkenylstannanes.

The known procedures for the conversion of alkenylstannanes into the corresponding fluoroalkenes suffer from largely variable yields and a limited compatibility with functional groups; most notably, protodestannation becomes a serious issue whenever protic sites are present in the substrate. Outlined in this paper is a convenient alternative with a much improved application profile, which is largely unperturbed by free alcohols and amides of all sorts. Key to success is the use of F-TEDA-PF6 in combination with non-hygroscopic and bench-stable silver phosphinate (AgOP(O)Ph2 ) that acts as an essentially neutral, non-nucleophilic promotor and effective tin-scavenger at the same time. This new method opens many opportunities for late-stage fluorination of elaborate compounds far beyond the scope of the literature procedures, as witnessed by the preparation of a fluorinated macrolide antibiotic, a fluorinated prostaglandin derivative, and a set of fluorinated amino acid surrogates and peptide isosteres.