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Pd-catalyzed aerobic oxidative coupling of arenes: evidence for transmetalation between two Pd(II)-aryl intermediates.

ABSTRACT: Pd-catalyzed aerobic oxidative coupling of arenes provides efficient access to biaryl compounds. The biaryl product forms via C-H activation of two arenes to afford a Pd(II)ArAr' intermediate, which then undergoes C-C reductive elimination. The key Pd(II)ArAr' intermediate could form via a "monometallic" pathway involving sequential C-H activation at a single Pd(II) center, or via a "bimetallic" pathway involving parallel C-H activation at separate Pd(II) centers, followed by a transmetalation step between two Pd(II)-aryl intermediates. Here, we investigate the oxidative coupling of o-xylene catalyzed by a PdX2/2-fluoropyridine catalyst (X = trifluoroacetate, acetate). Kinetic studies, H/D exchange experiments, and kinetic isotope effects provide clear support for a bimetallic/transmetalation mechanism.

SUBMITTER: Wang D

PROVIDER: S-EPMC4161672 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Pd-catalyzed aerobic oxidative coupling of arenes: evidence for transmetalation between two Pd(II)-aryl intermediates.

Wang Dian D Izawa Yusuke Y Stahl Shannon S SS

Journal of the American Chemical Society 20140630 28

Pd-catalyzed aerobic oxidative coupling of arenes provides efficient access to biaryl compounds. The biaryl product forms via C-H activation of two arenes to afford a Pd(II)ArAr' intermediate, which then undergoes C-C reductive elimination. The key Pd(II)ArAr' intermediate could form via a "monometallic" pathway involving sequential C-H activation at a single Pd(II) center, or via a "bimetallic" pathway involving parallel C-H activation at separate Pd(II) centers, followed by a transmetalation s ...[more]

PMID: 24965384

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