Observation of a “Cu(III)“ intermediate: Structure determination by NMR and density functional theory (DFT) calculations

ORGN 33

Steven H. Bertz, Complexity Study Center, Mendham, NJ 07945, Craig A. Ogle, cogle@uncc.edu, Department of Chemistry, University of North Carolina at Charlotte, Charlotte, NC 28223, and James P. Snyder, jsnyder@emory.edu, Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322.

Text Box: It has long been proposed that an organo-Cu(III) (i.e. C-tetravalent Cu(I)) intermediate is the essential agent promoting cuprate-mediated conjugate addition to α,β-unsaturated carbonyl groups.  Using DFT calculations, we have examined substitutent effects on the stability of square-planar cuprate anions.  The cyanide ligand is suggested to impart relatively high stability.  Accordingly, compound 1 has been observed by NMR at -100 °C and the two-bond coupling constants (13C-Cu-13C) determined (see accompanying abstract).  A second application of DFT to calculate 2JCC‘s for models of 1 supports the tetravalent nature of copper, its square-planar geometry and the arrangement of ligands around the metal.

 

 

 

Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
8:00 AM-11:40 AM, Sunday, 10 September 2006 Moscone Center -- Room 133, Oral

Division of Organic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006