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
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.