Concave Reagents, 15[1]. New Concave 1,10‐Phenanthrolines: Catalysts for the Alcohol Addition to Ketenes and Ligands in Transition Metal Complexes

By bridging tetrahydroxy‐1,10‐phenanthrolines 9 by ditosylates 10 or diiodides 11 concave 1,10‐phenanthrolines 1 were synthesized. Their concave shape was proven by X‐ray analyses of 1a and 1c , their basicities were determined by photometric titrations. Compounds 1a‐g are active in the basecatalyzed addition of alcohols to ketenes and form stable metal ion complexes with transition metal salts.