Work

Sterically Induced Acceleration of Aryl Halide Activation by Pd(0): A Radical Alternative to 2-Electron Oxidative Addition

Year: 2025

Type: article

Abstract: The first elementary step of Pd (0) -catalyzed cross-coupling involves the activation of an aryl halide by a Pd (0) catalyst, which is widely assumed to proceed in a formal 2-electron process, involving concerted cleavage of the aryl halide bond and formation of an aryl-Pd bond as to generate a Pd (II) complex. Contrary to common reactivity assumptions under this mechanistic manifold, we observed that severe steric hindrance in the aryl halide and catalyst did not inhibit the thermal activation of the aryl halide but instead greatly accelerated it, giving full conversion of an ortho, ortho- di- tert -butyl-substituted aryl bromide in 1 min at room temperature on gram scale with a bulky Pd (0) catalyst. Our mechanistic data revealed that a 1-electron-based halogen abstraction by Pd (0) is operative in such sterically demanding settings.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c04407

Authors: Daniel Hupperich, Jaime Ponce-de-León, Ignacio Funes-Ardoiz, Theresa Sperger, Franziska Schoenebeck

Institution: RWTH Aachen University

Language: English

Topic: Catalytic Cross-Coupling Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: Alexander von Humboldt-Stiftung, Fonds der Chemischen Industrie, RWTH Aachen University, European Research Council