Ni(I)–Alkyl Complexes Bearing Phenanthroline Ligands: Experimental Evidence for CO2 Insertion at Ni(I) Centers

Although the catalytic carboxylation of unactivated alkyl electrophiles has reached remarkable levels of sophistication, the intermediacy of (phenanthroline)­Ni­(I)–alkyl speciescomplexes proposed in numerous Ni-catalyzed reductive cross-coupling reactionshas been subject to speculation. Herein we report the synthesis of such elusive (phenanthroline)­Ni­(I) species and their reactivity with CO2, allowing us to address a long-standing question related to Ni-catalyzed carboxylation reactions.