The stereoselective synthesis of enantiomerically pure single‐wing‐functionalized tribenzotriquinacenes using the enzyme CAL‐B was successfully extended towards operating on a multi‐gram scale. Based on the (P)‐tribenzotriquinacene‐2‐carbaldehyde (P)‐6 obtained in >99 % ee, the hitherto unknown (P)‐2‐hydroxy‐ and (M)‐2‐hydroxy‐3‐iodo‐TBTQ derivatives (P)‐9 and (M)‐10 were prepared in optically pure form. The bowl‐shaped ortho‐iodophenol (M)‐10 was subjected to a twofold crosswise Ullmann‐type condensation to give, albeit in low yield (10 %), the 1,4‐dioxine 5, in which two TBTQ bowls are fused exclusively in a syn‐bi‐concave orientation, thus demonstrating a new example for a chirality‐assisted synthesis. The corresponding Ullmann condensation of the racemic TBTQ‐ortho‐iodophenol rac‐10 furnished the respective anti‐bis‐TBTQ‐dioxine 11 as the major diastereomer together with the syn‐isomer 5 in the same total yield and in a 11/5 ratio of at least 4. The two diastereomeric bis‐TBTQ‐dioxines show minor but significant differences in most of the characteristic 1H‐NMR chemical shifts. The solid‐state structure of the syn‐dimer 5, determined by X‐ray diffraction, was found to consist of pairs of host–guest complexes, [5·CH2Cl2]2, with pronounced face‐to‐face orientation of the bi‐concave host molecules.

The Front Cover shows the solid‐state structure of a syn‐biconcave tribenzotriquinacene dimer synthesized by chirality‐controlled two‐fold crosswise Ullmann‐type condensation of an enantiomerically pure TBTQ‐based ortho‐iodophenol with (M)‐configuration (X = I, Y = OH). Such highly bowl‐shaped building blocks with single‐wing functionalization at the aromatic periphery were obtained on a gram‐scale via enantioselective enzyme‐catalyzed ester hydrolysis in the key step. More information can be found in the https://doi.org/10.1002/ejoc.201800465