Synthesis of bromoundecyl resorc[4]arenes and applications of the cone stereoisomer as selector for liquid chromatography
As an extension of our studies on the multifaceted properties of C-alkylated resorc[4]arenes, we planned to immobilize on a solid support resorc[4]arenes with C11-long side chains in the lower rim. To this purpose, we synthesized two conformationally diverse resorc[4]arenes containing a bromoundecyl moiety in the four axial pendants. The cone stereoisomer 6a (30% yield) was selected for the reaction with an aminopropylated silica gel (APSG) obtained from spherical Kromasil Si 100, 5 μm particles, to give the corresponding immobilized SP-C11-resorc[4]arene system.