Experimental and computational studies on the mechanism of N-heterocycle C-H activation by Rh(I)

J Am Chem Soc. 2006 Feb 22;128(7):2452-62. doi: 10.1021/ja0576684.


Evidence is presented for a proposed mechanism of C-H activation of 3-methyl-3,4-dihydroquinazoline (1) by (PCy(3))(2)RhCl. One intermediate (3), a coordination complex of 1 with (PCy(3))(2)RhCl, was identified along the path to the Rh-N-heterocyclic carbene product of this reaction (2). Isotopic labeling and reaction-rate studies were used to demonstrate that C-H activation takes place intramolecularly on the reaction coordinate between 3 and 2. Computational studies corroborate the proposed mechanism and suggest that the rate-limiting step is oxidative addition of the C-H bond to the metal center. The consequences of this mechanism for coupling reactions of N-heterocycles that occur via Rh-catalyzed C-H bond activation are discussed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Catalysis
  • Crystallography, X-Ray
  • Kinetics
  • Models, Molecular
  • Molecular Structure
  • Quinazolines / chemistry*
  • Rhodium / chemistry*
  • Thermodynamics


  • Quinazolines
  • Rhodium