Experimental and computational studies on the mechanism of N-heterocycle C-H activation by Rh(I).
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.
Department of Chemistry, University of California, and Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Sean H
SH
Wiedemann
Jared C
JC
Lewis
Jonathan A
JA
Ellman
Robert G
RG
Bergman
D002384:Catalysis; D018360:Crystallography, X-Ray; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D011799:Quinazolines / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D013816:Thermodynamics
D011799:Quinazolines; D012238:Rhodium