A high yielding route to the (-)-platensimycin core is communicated. This entailed the discovery of Bi(OTf)(3) to catalyze a Friedel-Crafts cyclization of a free lactol, supplemented by LiClO(4) to suppress the Lewis basicity of the sulfonate group. After TBAF-promoted cyclodearomatization, a diastereoselective conjugate reduction of a dienone was achieved by adopting amine-based organocatalytic rationales to reverse the inherent steric control of the substrate.