Classical approaches to the BOB framework have been based on nucleophilic addition of stoichiometric organometallics to a borylated arene bearing an adjacent carbonyl, or borylation of an ortho-halo benzyl alcohol derivative using Miyaura-type conditions (Scheme 1a). Con-temporary approaches include B-insertion strategies using B-Br reagents (Scheme 1b), such as a dual Ni/Zn catalysis to insert a boron unit into the C(sp 3 )-O bond of benzodihydrofurans by Dong and coworkers, and the electrophilic haloboration approach reported by Ingleson and coworkers to directly access benzoxaboronines from oalkynyl phenols. A complementary approach that does not rely upon electrophilic borylating agents or C-B bond formation was developed by Sheppard and coworkers, where gold catalysis generated the benzoxaborinine from o-alkynyl boronic acids. An attractive synthetic approach to BOB compounds is through [2+2+2]cycloaddition. The main advantages over other approaches are its high atom efficiency and the rapid generation of molecular complexity using modular components. First disclosed in 1890 by Berthelot, 51 this procedure has been improved considerably using transition metal catalysis, initially by Reppe, and it is now extensively used in a variety of fields from pharmaceutical and natural product synthesis to polymer chemistry. In the context of BOB synthesis, the [2+2+2]cycloaddition approach has seen limited development. Elegant work from Yamamoto and co-workers used ruthenium catalysis to generate benzoxaboroles through trimolecular [2+2+2]cycloaddition wherein an alkyne boronic ester was used to template diyne formation by in situ transesterification using a propargylic alcohol (Scheme 1c). Here we report the development of a method for the direct, modular, and regioselective synthesis of complex BOB scaffolds using Rh-catalyzed [2+2+2]cycloaddition, which uses chelation-assistance to overcome an innate steric inhibition (Scheme 1d).