An Approach to Optically Pure Bridging Chiral p-tert-Butylcalix[4]arenes through a Homologous Anionic Ortho-Fries Rearrangement.

A novel efficient approach to optically pure bridging chiral calix[4]arenes through a homologous anionic ortho-Fries rearrangement of inherently chiral calix[4]arenes was presented for the first time. As a result, two pairs of N,N′-dimethylformamidyl-substituted bridging chiral p-tert-butylcalix[4]arene enantiomers were facilely obtained. Their absolute configurations were determined through ROESY analysis, ECD comparison, and X-ray crystallographic analysis. [ABSTRACT FROM AUTHOR]