COMMUNICATIONS
Strained Dehydrogenative Ring Closure of Phenylcarbazoles
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[10] See the Supporting Information.
[11] Given the large excess of pivalic acid and the relatively
high temperature, it is safe to assume that under the re-
action conditions, at least part of the Ag2O and CuO
salts are converted to AgOPiv and Cu(OPiv)2, by
simple water displacement. In any case, we showed that
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neither Ag nor Cu are essential to the C H activation
events (respectively, experiments IV and V, Scheme 5).
This seems to indicate that neither Ag2O nor AgOPiv
significantly act as external base, but solely as oxidant.
This is also in line with the observation of a thin layer
of Ag(0) mirror inside the glass reactor.
Adv. Synth. Catal. 2015, 357, 945 – 949
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