Regioselective Functionalization of the para-Positions at the Calix[4]arene Upper Rim

This review summarized and systematized the currently known methods of substituting phenolic fragments of calix[4]arenes in the para-position, mainly focusing on the conditions of regioselective carrying out such processes. The reactions of the further transformation of the inserted functional groups, which allows the expansion of the family of para-substituted calixarenes, are also considered. These reactions can be used in the synthesis of inherently chiral calix[4]arenes with asymmetric substitution on the upper rim.