Amidoresorcinarenes were prepared from achiral resorcinarene scaffolds with amino acids as chiral building blocks. CD spectra of the macrocycles show their enantiomeric nature with four (S)- and (R)-phenylalanine residues, respectively.
The cavity of inherently chiral resorcinarenes was extended via a quadruple intramolecular coupling reaction giving a tetrabiaryl ether with four new stereogenic axes. The configuration was elucidated by X-ray analysis and by CD spectroscopy to be of (M,M,M,P) chirality in the (M,R) enantiomer.
For complexation experiments in the gas phase monitored by mass spectrometry two pairs of quasi-racemates were synthesised with one enantiomer terminally labelled in the alkyl chains. Complexes were generated the chiral resorcinarene and chiral amino alcohols, amino acid esters and amino acids, respectively.
In ligand exchange experiments monitored by means of ESI-FT-ICR mass spectrometry with some amino bases the reaction rates were determined. The entioselectivities were in the range of 0.4 < rho < 3.88.