Strain‐Release Pentafluorosulfanylation and Tetrafluoro(aryl)sulfanylation of [1.1.1]Propellane: Reactivity and Structural Insight**
Yannick Kraemer, Clément Ghiazza, Abbey N. Ragan, Shengyang Ni, Sigrid Lutz, Elizabeth K. Neumann, James C. Fettinger, Nils Nöthling, Richard Goddard, Josep Cornellà, Cody Ross Pitts
Abstract
Abstract We leveraged the recent increase in synthetic accessibility of SF 5 Cl and Ar−SF 4 Cl compounds to combine chemistry of the SF 5 and SF 4 Ar groups with strain‐release functionalization. By effectively adding SF 5 and SF 4 Ar radicals across [1.1.1]propellane, we accessed structurally unique bicyclopentanes, bearing two distinct elements of bioisosterism. Upon evaluating these “hybrid isostere” motifs in the solid state, we measured exceptionally short transannular distances; in one case, the distance rivals the shortest nonbonding C ⋅⋅⋅ C contact reported to date . This prompted SC‐XRD and DFT analyses that support the notion that a donor‐acceptor interaction involving the “wing” C−C bonds is playing an important role in stabilization. Thus, these heretofore unknown structures expand the palette for highly coveted three‐dimensional fluorinated building blocks and provide insight to a more general effect observed in bicyclopentanes.