Surface immobilized Cu-1,10-phenanthroline complexes with -aminophosphonate groups in the 5-position as heterogenous catalysts for efficient atom-transfer radical cyclizations

Many Cu catalyzed ATRC reactions suffer from low catalyst activity and stability. We have synthesized five 1,10-phenanthroline ligands substituted in the 5-position with alpha-aminophosphonate groups, through which the corresponding Cu complexes can be immobilized on Al2O3. These catalysts show similar activity and higher selectivity than the homogenous catalysts while being recyclable.