Chiral Derivatives of 2‑Aminotribenzotriquinacene: Synthesis and Optical Resolution

Starting
from a hitherto unknown 2-aminotribenzotriquinacene, several
2-amino-3-X-substituted TBTQ derivatives, all bearing a single ortho-difunctionalized indane wing, were synthesized as
rigid and chiral building blocks for the potential construction of
complex supramolecular architectures. Efficient access to two pairs
of enantiomeric TBTQ derivatives, namely, the peripheral ortho-nitroaniline (X = NO2) and the related anthranilic acid
(X = CO2H), was developed using chiral auxiliaries as the
resolving reagents. The structure of the intermediate diastereomers
was confirmed by 1H and 13C NMR spectroscopy,
high-resolution mass spectroscopy (HRMS), and polarimetry. The absolute
configuration of the optically active derivatives was confirmed by
quantum chemical time-dependent density functional theory (TD-DFT)
calculations of the theoretical electronic circular dichroism (ECD)
spectra and by single-crystal X-ray structure analysis of a synthesis
intermediate.