Stacked Aryl Groups in P-Resolved Cyclic Phosphonamides as a new conformational constrain

Along the lines of a systematic investigation of conformational constraints promoted by weak interactions, the aryl stacked structures of some chiral cyclic phosphonamides, synthesised with the aid of Betti bases as chirality inducers, were investigated by X-ray diffraction analysis and NMR spectroscopy. The sysnthesised systems shown the stacked conformation between two of their aryl groups leading to a pre-organized structures. The π−π stacking motif between the aromatic rings was observed either in solid state and in solution suggesting that this supramolecular synthon could be used as conformational constraining tool in the development of drug molecule candidates based on chiral cyclic phosphonamides. The disabling of the π−π stacking motif was pursued by adding an ortho-substituent on one aromatic ring.