SYNTHESIS OF UPPER AND LOWER RIM BINAPHTHYL BRIDGED CALIX[4]ARENES - NEW POTENTIAL CHIRAL HOSTS FOR MOLECULAR RECOGNITION AND CATALYSIS

New chiral upper and lower rim (R)-binaphthyl-bridged calix[4]arenes i n the cone conformation (5, 10, 11, 15, 17, 18) have been synthesized by exploiting the selective functionalization of the calix[4]arene ske leton, The conformational properties of the new hosts in CDCl3 and DMS O-d(6) have been clarified by dynamic NMR measurements, and their comp lexation properties toward neutral molecules, alkali metal, and silver (I) cations have been explored. The upper rim binaphthyl-bridged calix [4]arene 5 is able to form a 1:1 complex with Ag+ in CDCl3:CD3OD 1:1 v /v solution, where the silver cation is encapsulated into the apolar c avity. The determined association constant (log K = 3.51) is substanti ally higher than for unbridged calix[4]arenes in the cone conformation . These new macrobicyclic compounds are potential hosts for chiral rec ognition and catalysis.