Accounting for Strong Ligand Sensitivity in Pd-Catalyzed α-Arylation of Enolates from Ketones, Esters, and Nitroalkanes.

ABSTRACT: The mechanism of the Pd-catalyzed α-arylation of three model enolates is studied focusing on an analysis of their very different reactivities. In particular, the low reactivity of nitronates under standard arylation conditions and their high sensitivity to the nature of catalytic systems are addressed. The three canonical steps for each of the reaction systems are examined, and key trends surrounding the stability of intermediates and transition states are delineated. A framework based on molecular orbital analyses and the hard-soft acid-base (HSAB) theory is advanced to explain the observed reactivity trends. The local softness of the enolates was found to be a key parameter controlling the energy of the enolate-catalyst complexes. The low reactivity of the nitroalkane enolates is attribu

SUBMITTER: Tcyrulnikov S 

PROVIDER: S-EPMC7061083 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature