Takateru Kubota

Novel Amide‐Based Molecular Knots: Complete Enantiomeric Separation, Chiroptical Properties, and Absolute Configuration

By comparison of experimental and theoretical CD curves the absolute configurations of chromatographically baseline-separated enantiomers of new trefoil molecular knots could be determined. From the results of syntheses with differently substituted starting materials, conclusions can be drawn about the knot-formation mechanism.

Chiral Dendrophanes, Dendro[2]rotaxanes, and Dendro[2]catenanes: Synthesis and Chiroptical Phenomena

New chiral dendrimers with planar-chiral, cycloenantiomeric and topologically chiral cores were prepared in yields of up to 90% starting from a racemic 4-hydroxy[2.2]paracyclophane, a [2]rotaxane with sulfonamide groups in the wheel and axle positions and [2]catenane with a sulfonamide group in both of its macrocycles. The separation of the racemic mixture of these dendrimers was possible by HPLC on chiral stationary phases. The CD spectra of the dendro[2.2]phanes showed a hitherto unknown influence of the dendritic part on the intensities of the Cotton effects. The chirality of these dendrimers is dependent not only on its chiral elements but also on its dendritic wedges and their generation.