Scheme 1. (A) Evolution of α,α-Difluorocyclopropanes as New Drug Discovery Modules; (B) n → π* Interaction in Biology and Isostere Design.; (C) Catalysis-Based Strategy to Enable the Direct Conversion of Bicyclobutanes to cis-α,α-Difluorocyclopropanes Enabled by I(I)/I(III) Organocatalysis.