Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF- and CFSF-containing [2]staffanes.

Selectivity in radical chain oligomerizations involving [1.1.1]propellane - i.e., to make []staffanes - has been notoriously challenging to control when > 1 is desired. Herein, we report selective syntheses of SF- and CFSF-containing [2]staffanes from SFCl and CFSFCl, demonstrating cases whereby oligomerization is preferentially truncated after incorporation of two bicyclopentane (BCP) units. Synthetic and computational studies suggest this phenomenon can be attributed to alternating radical polarity matching. In addition, single-crystal X-ray diffraction (SC-XRD) data reveal structurally interesting features of the CFSF-containing [2]staffane in the solid state.