Chirality transfer & molecular propellers

The fascinating stereochemistry of molecular propellers – both static and dynamic – have attracted a lot of attention in the last two decades.

We demonstrated for the first time that the ECD spectra of trityl-protected monoalcohols are highly sensitive to the chirality (absolute configuration) of the alcohol. The transmission of chirality from an alcohol chiral center to the trityl group through a molecular “bevel gear” mechanism is directly observed.

Effective chirality transmission is not reserved for systems in which the inductor and the receptor (trityl) are in immediate proximity, but extends over a distance of about 4 Å utilizing a rigid amide frame and weak intramolecular interactions.

Comparable sensitivity in chirogenesis was reported for a supramolecular system based on the formation of a complex between chiral amines and the ethane-bridged bis(zincporphyrin).

Figure 4