Catalytic Aldehyde and Alcohol Arylation Reactions Facilitated by a 1,5-Diaza-3,7-diphosphacyclooctane Ligand
Eric S. Isbrandt, Amrah Nasim, Karen Zhao and Stephen G. Newman*
*Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada,
Email: stephen.newman
uottawa.ca
E. S. Isbrandt, A. Nasim K. Zhao, S. G. Newman, J. Am. Chem. Soc., 2021, 143, 14646-14656.
DOI: 10.1021/jacs.1c05661
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Abstract
A Ni complex with a 1,5-diaza-3,7-diphosphacyclooctane ligand catalyzes a reductive or redox-neutral coupling of aryl iodides with either aldehydes or alcohols, respectively. The P2N2 ligand was found to avoid deleterious aryl halide reduction pathways that dominate with more traditional phosphines and NHCs.
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proposed mechanism
General Procedure: The redox neutral cross-coupling of aryl iodides and primary alcohols
Inside the glovebox, to a dry 8 mL screw-capped reaction vial equipped with a magnetic stir bar, NiBr2•diglyme (0.10 equiv, 0.03 mmol, 10.6 mg) and (PCyNArCF3)2 (0.30 equiv, 0.09 mmol, 54.2 mg) were added and dissolved in toluene (1.5 mL). Solution was stirred. 2,2,6,6-tetramethyl piperidine (2 equiv, 0.6 mmol, 84.7 mg) and aryl iodide (1 equiv, 0.3 mmol) were added to the vial followed by primary alcohol (2.5 equiv, 0.75 mmol). The vial was capped, removed from the glove box, and placed in a stirring (350 rpm) mineral oil bath pre-heated to 75°C. After stirring for 16 hours, the reaction vial was removed from the oil bath and cooled down to room temperature. An aliquot was filtered through silica and analyzed by GC-MS to assess crude alcohol:ketone ratio. The reaction was diluted with DCM, dried in vacuo, and purified by column chromatography.
Key Words
ID: J48-Y2021
