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equipment used for circuit development and helpful discussions;
and Dr Laura Tedone for assistance with mass spectrometry.
T. P. N. and J. C. R. thank the Australian Government for Research
Training Program Scholarships.
Conflicts of interest
There are no conflicts to declare.
Notes and references
1
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4 6
Scheme 1 (A) Results employing [Cu(MeCN) ]PF , Xantphos (XP), and bath-
ocuproine (bcp). (B) Cu-catalysed hydrodebromination of bromide 12.
a
19
(
C) Tentative mechanistic hypothesis. Determined by F NMR spectroscopy
with the aid of a calibrated internal standard (average of 2 experiments).
1
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1
3 was formed exclusively in 54% yield (Scheme 1B). This
observation is consistent with the reported faster fragmenta-
tion of bromides from radical anions leading to aryl radicals, in
4
1
4
comparison to the analogous fragmentation of fluorides.
Furthermore, electrochemical characterisation of C NHAc (3a)
(2) (E1/2 = ꢀ1.64 V vs.
´
6 5
H
15
I/0
(E
1/2 = ꢀ1.60 V vs. SCE) and [Cu(bcp)(XP)]PF
6
11
SCE) suggests that an electron transfer process may take place in
this chemistry. A tentative outline of the mechanistic pathway
responsible for the reaction is provided in Scheme 1C. Subsequent
studies will focus on exploring the mechanism of this copper-
catalysed reaction in more detail.
6
7
(a) S. M. Senaweera, A. Singh and J. D. Weaver, J. Am. Chem. Soc., 2014,
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In summary, pulsed LED irradiation was exploited to develop a
novel copper-photocatalysed C–F functionalisation reaction. This
strategy was crucial for establishing a more efficient process. The
results of this proof-of-concept study highlight the generally
untapped potential of pulsed LED irradiation in organic synthesis.
Indeed, when coupled with advances in catalyst development, we
suggest that this may represent a powerful approach that can
contribute to extending the applications of earth-abundant, base
metals in photoredox catalysis. We suggest that our findings may
6
1
7
, 7206; (c) S. Senaweera and J. D. Weaver, J. Am. Chem. Soc., 2014,
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8
also have a broader significance in organic synthesis. Subsequent 10 T. P. Nicholls, G. E. Constable, J. C. Robertson, M. G. Gardiner and
A. C. Bissember, ACS Catal., 2016, 6, 451.
studies will focus on extensively investigating the reasons for
1
1 E. Mejia, S.-P. Luo, M. Karnahl, A. Friedrich, S. Tschierlei, A.-E.
Surkus, H. Junge, S. Gladiali, S. Lochbrunner and M. Beller,
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enhanced reaction rate and efficiency provided by pulsed irradia-
tion, in addition to exploring the wider applications of this
strategy in synthesis.
We gratefully acknowledge the University of Tasmania (UTAS),
PhosAgro/UNESCO/IUPAC for a Green Chemistry for Life Grant
1
3
2 Lewis acid Gd(OTf) , or related species, may coordinate compounds
3a and/or 4a and lower their respective redox potentials.
1
3 B. Michelet, C. Deldaele, S. Kajouj, C. Moucheron and G. Evano, Org.
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1
1
(A. C. B.), and Collier Charitable Fund Grant (A. C. B.) for financial
support; UTAS Central Science Laboratory for providing an access
to NMR spectroscopy services; Mr Paul Weller for providing
Chem. Commun.
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