Nickel-Catalyzed\nRegio- and Stereoselective Hydroalkylation\nof Allenes: Exploiting the Unique Reactivity of Diazo Compounds as\nan Alkylating Source

The reactivity of allenes has historically been limited\nwith no\nprevious examples of their hydroalkylation using diazo compounds in\nany transition-metal catalytic framework. In this study, we present\na Ni-catalyzed regio- and stereoselective hydroalkylation reaction\nof allenes utilizing diazo compounds as alkylating agents. The success\nof this method can be attributed to the use of a pyridine-based P,N\nligand, which combines the advantages of both phosphine and nitrogen\nligands. Additionally, the carbonyl group in the diazo compound facilitates\nthe formation of stable intermediates. Our detailed mechanistic studies\nreveal that the reaction proceeds through an initial interaction with\nthe diazo compound, followed by engagement with the allene.