2,14-Dithiacalix[4]arene and its homooxa analogues: synthesis and dynamic NMR study of conformational behaviour

Chem Commun (Camb). 2015 Apr 25;51(32):7051-3. doi: 10.1039/c5cc00819k. Epub 2015 Mar 25.

Abstract

A simple and scalable synthesis of 2,14-dithiacalix[4]arene with alternating bridges (-CH2- and -S-) is reported. Proper selection of the bisphenol-based starting building blocks can provide not only the title compound (58%) but also yet unreported homooxa analogues possessing three different bridging units (-CH2-, -S- and -CH2-O-CH2-) in the molecule. These systems exhibit interesting conformational behaviour allowing for the study of flip-flop motion of the circular hydrogen bond arrays using dynamic NMR techniques.