Calix(4)arene ligands with phosphorus-containing groups tethered at the upper rim

Research was conducted to examine a new mechanism for the preparation of upper-rim functionalized calix(4)arenes bearing distal P-containing substituents. It comprises the starting point for the synthesis of entire families of calixarenes having metals across the upper rim. The dinuclear rhodium complex was found to exhibit useful catalytic activity for the hydroformylation of olefins.