CrossRef enabled

PAC Archives

Archive →

Pure Appl. Chem., 2011, Vol. 83, No. 3, pp. 655-665

Published online 2011-02-07

An oxidative carbon–carbon bond-forming reaction proceeds via an isolable iminium ion

Althea S.-K. Tsang1, Paul Jensen1, James M. Hook2, A. Stephen K. Hashmi3 and Matthew H. Todd1*

1 School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
2 NMR Facility, Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia
3 Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany

Abstract: The mechanism of our previously reported DDQ-mediated oxidative C–C bond-forming reaction is investigated. We are able to trap and characterize an iminium ion intermediate with X-ray crystallography, elemental analysis, and solid-state NMR spectroscopy; to our knowledge this is the first time this putative intermediate ion has been directly observed in such cross-dehydrogenative couplings (CDCs). The intermediate can be reacted with a range of nucleo-philes, including a malonate that is not amenable to a one-pot reaction protocol.