Edge Article
Chemical Science
Acknowledgements
We are grateful to Eli Lilly and Company (Lilly Research Award
Program, LRAP) and the DOE (DE-FG02-05ER15690) for fund-
ing. Spectroscopic instrumentation was partially supported by
a generous gi from Paul J. and Margaret M. Bender, the NIH
(1S10 OD020022-1) and the NSF (CHE-1048642).
Scheme
2 Simplified oxidase-type mechanism for Cu-catalyzed
aerobic oxidative N–N coupling reactions.
Inhibition of the reactions by the substrates suggests that
one or more coordinated substrate molecules must dissociate
from CuI prior to the reaction with O2.34 For imine homocou-
pling, the reaction of Cu with O2 is promoted by pyridine. This
observation could arise from electronic effects, as pyridine is
observed to lower the CuII/I potential, or a steric effect arising
from the smaller steric inuence of pyridine relative to the
benzophenone imine. Steric effects will be amplied by the
involvement of two Cu species in the turnover limiting reaction
with O2, evident by the second order dependence of the reaction
on [Cu] (Fig. 1B and 2B).
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Conflicts of interest
There are no conicts to declare.
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Chem. Sci.