Biconcave and Convex–Concave Tribenzotriquinacene Dimers

A new chiral tribenzotriquinacene bearing an ortho-bromoaniline nucleus was synthesized and optically resolved. The individual enantiomers, the absolute configuration of which was confirmed by single-crystal X-ray structure analysis, were stereoselectively converted into the same pyrazine-fused syn-bis-TBTQ derivative by chirality-assisted Buchwald–Hartwig amination. The corresponding diastereomeric anti-dimer was obtained alongside the syn-dimer from the racemic sample under similar reaction conditions. X-ray structure analysis of the dimers confirmed the mutual biconcave and convex–concave configuration of their TBTQ moieties and the preservation of the orthogonal orientation of the indane wings within each of them.