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Exploiting "DalPhos" Ligands in Challenging Cross-Coupling Reactions





 email this page to a friendProf. Mark Stradiotto
 Prof. Mark Stradiotto
 Faculty of Science Killam
 Professor of Chemistry


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Overview:

Palladium-catalyzed cross-coupling has emerged as an effective synthetic methodology that is employed in both academic and industrial settings for constructing C-C, C-N and other sigma-bonds. Significant research effort has been directed toward evaluating how modifying various reaction parameters, perhaps most notably the ancillary co-ligand, influences the outcome of the cross-coupling reaction. Consequently, several highly effective classes of ligands/catalysts have emerged that offer broad substrate scope at relatively low catalyst loadings. Despite such progress, a number of challenges still remain, including the establishment of highly efficient and selective catalysts that can monoarylate simple and abundant substrates that feature multiple reactive C-H or N-H bonds.

My research group has initiated a program employing P,N "DalPhos" ligands as alternatives to more traditional ligand archetypes in palladium-catalyzed C-C and C-N bond-forming reactions; our recent progress in this area will be presented. Notably, the Mor-DalPhos ligand represents the state-of-the-art in the palladium-catalyzed monoarylation of small nucleophilic substrates, including ammonia, hydrazine, and acetone, and has also proven to be highly effective in the gold-catalyzed hydroamination of internal aryl alkynes with dialkylamines. In many cases, the reactions can be performed at relatively low catalysts loadings, with excellent functional group tolerance and chemoselectivity. Preliminary results of coordination chemistry and stoichiometric reactivity studies that seek to provide insight into the behavior of our P,N-ligands in this catalytic chemistry will also be presented.

Crystal structure of the [(Mor-DalPhos)Pd(Ph)Cl] coordination complex:
(derived from oxidative addition of PhCl to“(Mor-DalPhos)Pd(0)”)

Areas covered in the webinar:

  • Overview of Buchwald-Hartwig amination (ligand design, catalytic cycle)
  • Development of the DalPhos ligand family
  • Reactivity applications in monoarylation (ammonia, hydrazine, acetone)
  • Stoichiometric reactivity studies directed toward understanding the behavior of the Mor-DalPhos ligand in catalytic chemistry

Who should attend?

  • Organic Chemists
  • Organometallic Chemists
  • Pharmaceutical Chemists
  • Anyone involved in synthetic methodology in academic or corporate labs