Our strategy to tackle this challenging cyclization revolved around the use of an optimally preorganized template, that could both: 1) orient the reacting groups in a way that maximizes intramolecular reactivity over intermolecular oligomerization (substrate geometric preorganization, Figure and) and 2) partially compensate for product ring strain by designing a frustrated starting material that adopts a product-like torsional profile around key dihedral angles (ground state destabilization). Some degree of flexibility must still be present to allow interconversion among stereoisomeric conformations of the starting material, allowing for a stereoconvergent and stereogenic process to take place. With the synthetic target of dibenzodiazepinones in mind, we envisioned that a central N-alkyl, N-aryl amide on the starting material could provide the desired conformational bias to favor s-cis conformations of the side aryl rings (Figure ) . As a key disconnection, we elected one of the diarylamide C-N bonds through a superbase-mediated SNAr cyclization from the respective acyclic sulfonamide aryl fluoride. The sulfonamide nucleophile could be further preorganized for intramolecular attack by placing a blocking group in a neighboring position, tilting the nitrogen nucleophile towards the inner region of the ring. This set of properties delineated substrate 2a as an ideal candidate for the desired reactivity, which was synthesized in 5 steps from commercial starting materials. Under mild basic conditions, we were pleased to observe the rapid and selective conversion of 2a to product 3a (Figure ). Notably, no dimeric nor oligomeric products were detected. To our knowledge, this constitutes the first example of the formation of this challenging type of inherently chiral scaffold under mild conditions. Calcium oxide proved to be the best stoichiometric reagent to affect catalyst turnover while possessing negligible background reactivity as an achiral base. Presumably, this is due to its low solubility in the reaction solvent and due to the driving force of the formation of stable, insoluble calcium fluorides alongside the catalyst freebasing reaction. While different catalyst classes were effective for the reaction, asymmetric induction proved challenging. A series of known and effective (super)basic catalysts were explored, as well as chiral cations under phasetransfer conditions, but low enantioinduction was observed throughout (see Figure for more catalyst screening data). Initially, peptidyl guanidines provided the best selectivity (up to 64:36 er). However, we found that Nuñez-Dixon iminophosphorane 1c , which provided comparable selectivity to peptidyl catalysts in chloroform (65:35 er), provided a significant boost of selectivity in toluene (85:15 er). Following this promising lead, we conducted a few rounds of catalyst optimization that identified catalyst 1d as the best performing, delivering product 3a in 88% yield and 92:8 er under optimized conditions. To our knowledge, these results constitute the first and only observations of catalyst-controlled enantioselectivity for medium-sized ring cyclization in the absence of local stereogenic elements. Fine-tuning of iminophosphorane 1c to 1d was guided by the latest developments on this class of catalysts from the Dixon group, where these proved highly selective for Michael addition reactions and other transformations .