Visible-Light-Mediated Liberation and In Situ Conversion of Fluorophosgene

Article abstract of DOI:10.1002/chem.201804603

The first example for the photocatalytic generation of a highly electrophilic intermediate that is not based on radical reactivity is reported. The single-electron reduction of bench-stable and commercially available 4-(trifluoromethoxy)benzonitrile by an organic photosensitizer leads to its fragmentation into fluorophosgene and benzonitrile. The in situ generated fluorophosgene was used for the preparation of carbonates, carbamates, and urea derivatives in moderate to excellent yields via an intramolecular cyclization reaction. Transient spectroscopic investigations suggest the formation of a catalyst charge-transfer complex-dimer as the catalytic active species. Fluorophosgene as a highly reactive intermediate, was indirectly detected via its next downstream carbonyl fluoride intermediate by NMR. Furthermore, detailed NMR analyses provided a comprehensive reaction mechanism including a water dependent off-cycle equilibrium.

Full text of DOI:10.1002/chem.201804603

A Journal of
Accepted Article
Title: Visible Light Mediated Liberation and in situ Conversion of
Fluorophosgene
Authors: Daniel Petzold, Philipp Nitschke, Fabian Brandl, Veronica
Scheidler, Bernhard Dick, Ruth M. Gschwind, and Burkhard
König
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.201804603
Link to VoR: http://dx.doi.org/10.1002/chem.201804603
Supported by

10.1002/chem.201804603
Chemistry - A European Journal
FULL PAPER
Visible Light Mediated Liberation and in situ Conversion of
Fluorophosgene
Daniel Petzold¶, Philipp Nitschke¶, Fabian Brandl, Veronica Scheidler, Bernhard Dick, Ruth M.
Gschwind, and Burkhard König*[a]
Abstract: We report the first example for the photocatalytic
generation of a highly electrophilic intermediate that is not based on
radical reactivity. The single electron reduction of bench stable and
commercially available 4-(trifluoromethoxy)benzonitrile by an organic
photosensitizer leads to its fragmentation into fluorophosgene and
benzonitrile. The in-situ generated fluorophosgene was used for the
preparation of carbonates, carbamates and urea derivatives in
moderate to excellent yields via an intramolecular cyclization
reaction. Transient spectroscopic investigations suggest the
reaction because they possess only limited reactivity and/or
were already exploited in thermal and photochemical reactions
(Fig. 1c).10 On the other hand, the C-OCF3 bond could only be
activated electrochemically or under harsh reaction conditions
so far.11 However, the photocatalytic N-OCF3 cleavage of
complex starting materials was reported very recently.12 To
address the need of a hazard- and metal-free access to highly
reactive C1 building blocks, we envisioned to cleave the C-OCF3
bond of a simple, commercially available aryl trifluoromethoxy
ether by photoredox catalysis. We identified 4-(trifluoromethoxy)-
benzonitrile as a suitable starting material, which can be cleaved
quantitatively into benzonitrile and fluorophosgene by an organic
photosensitizer (Fig. 1d). Furthermore, we investigated the
reaction mechanism by NMR kinetic and structural analyses and
propose a photo-reductive mechanism based on the results of
radical trapping experiments and excited state quenching
experiments monitored by transient spectroscopy.
formation of
a
catalyst charge-transfer complex-dimer as the
highly reactive
catalytic active species. Fluorophosgene as
a
intermediate, was indirectly detected via its next downstream
carbonyl fluoride intermediate by NMR. Furthermore, detailed NMR
analyses pro-vided a comprehensive reaction mechanism including
a water de-pendent off-cycle equilibrium.
Introduction
Carbonates, carbamates and urea derivatives are privileged
structures in organic synthesis and common motifs in
pharmaceuticals, pesticides and plastics (Fig. 1a).1 Many
methods for the synthesis of these compounds have been
described.2 The direct and most hazardous way is the use of
gaseous phosgene or its less reactive derivatives diphosgene
and triphosgene.3 However, handling of those compounds in the
lab or in industry plants requires special safety precautions due
to their severe toxicity.4 Alternative procedures utilize activated
or non-activated carbonates or ureas, which are either prepared
by reaction with phosgene or less efficiently from CO2 (Fig. 1b).2a,
5
Some of these procedures require harsh reaction conditions or
suffer from low reactivity and poor atom economy.2 Therefore,
there is still a significant demand for a less hazardous, practical
and easily controllable generation of reactive C1 building blocks.
Photoredox catalysis with organic photosensitizers has received
tremendous attention in the past years.6 Many useful
transformations without the need of metal catalysts were
discovered, exploiting the versatile reduction and oxidation
potentials of organic photocatalysts.7 The common requirement
for a typical photocatalytic reaction is the generation of a radical
species which can either react with another radical, a sp2/sp
center, a nucleophile or a metal complex.8 However, the
photocatalytic generation of intermediates with pure ionic
reactivity remains elusive because energy and single electron
transfer are the predominant reaction paths of all common
photocatalysts.9 But especially under photo-reductive conditions
most leaving groups are ionic species, e.g. halides, pseudo
halides or cyanide, which are neglected in the course of the
Figure 1. a) Structures of prominent carbamate or urea containing molecules
used in synthesis, pharmacy, agriculture and daily life. b) Structures of
phosgene and commonly employed alternatives. c) Typical leaving groups and
their reactivity profile in photoredox catalysis. d) Overview of the photocatalytic
fluorophosgene generation; Tf = trifluoromethanesulfonate, R = benzonitrile.
Results and Discussion
We began our investigation using 2-benzylaminoethanol (1a) as
a model substrate, Rhodamine 6G (P1) as a strongly reducing
photosensitizer, diisopropylethylamine (DIPEA) as electron
donor and trifluoromethoxybenzene (2a) as fluorophosgene
precursor in neat acetonitrile.14 However, no conversion of 2a
was observed (Table 1 entry 1). Switching to commonly
employed Ir(ppy)3 (P2) or to the recently reported, phenoxazine
based photosensitizer P3 did also not lead to fragmentation of
2a (entries 2-3).13 Therefore, trifluoromethoxybenzene derivative
2b bearing an electron withdrawing nitrile group was employed.
[a]
D. Petzold, P. Nitschke, F. Brandl, V. Scheidler, Dr. B. Dick, Dr. R.
M. Gschwind, Dr. B. König
Institut für Organische Chemie
Universität Regensburg
Universitätsstrasse 31, Germany
Burkhard.Koenig@chemie.uni-regensburg.de
This article is protected by copyright. All rights reserved.

10.1002/chem.201804603
Chemistry - A European Journal
FULL PAPER
Hence, the redox potential of 2b was much more accessible
(Ered(2a) = -3.0 V vs. SCE compared with Ered(2b) = -2.1 V vs.
SCE, see Fig. S1) and 2b showed slow conversion in the
presence of photosensitizer P2 (entry 4). The reaction was
significantly improved by switching to P3 giving full conversion of
2b and 1 (entry 5). Further optimization of the reaction lead to
conditions giving 3a in an excellent isolated yield (entry 6).
Control experiments revealed that without catalyst, light or
DIPEA no or only trace amounts of product could be obtained
(entries 7-9). Finally, we observed that the cleavage of 2b was
independent of the presence of 1 (entry 10).
demonstrated that also thiocarbamates can be obtained by this
method. The corresponding carbamates of the amino alcohols
prolinol, valinol and tyrosinol were isolated in moderate yields
(3r-3t), whereas tryptophanol and methioninol showed good to
excellent conversion to 3u and 3v, respectively. Finally, some
bioactive compounds were subjected to this method. Uridine and
ribothymidine as well as the antiviral drug ribavirin were
converted to 3w, 3x and 3y with low to moderate yields. Finally,
the beta-blocker propranolol, the neurotransmitter adrenalin and
the sympathomimetic ephedrine gave good yields of the cyclized
products (3z-3ab). To demonstrate the synthetic utility of the
reaction, a gram scale reaction, using 1a as substrate, was
performed. The corresponding product 3a was isolated with 70%
yield after a prolonged reaction time of 48 h.
Table 1. Optimization of the reaction conditions
Conversion of
2a/2ba
Conversion of
1aa
Entry
1
PC (mol%) / λ
P1 (10)
/ 455
2a 0%
0%
nm
2
P2 (2) / 455 nm
P3 (5) / 400 nm
P2 (2) / 455 nm
P3 (5) / 400 nm
P3 (2) / 400 nm
400 nm
2a 0%
0%
3
2a 0%
0%
4
2b 51%
2b 100%
2b 100%
2b 0%
40%
5
6b
7b
100%
100% [96%]
0%
8b, c
9b, d
10b, e
P3 (2)
2b 0%
0%
P3 (2) / 400 nm
P3 (2) / 400 nm
2b traces
2b 100%
traces
0%
General conditions: A mixture of 0.1 mmol of 1a, 2 eq. of 2b, the indicated
amount of PC, 4 eq. of DIPEA in neat MeCN (0.1 M) under N2 atmosphere
were irradiated for 24 h with 400 nm light (or 455 nm for P1 and P2). a:
Conversion determined by GC-FID, isolated yield of 3a in brackets. b: A
mixture of 0.1 mmol of 1a, 1.05 eq. of 2b, 2 mol% P3, 3 eq. of DIPEA in dry
MeCN (0.1 M) under N2 atmosphere were irradiated for 24 h at 400 nm. c: no
light, 48 h. d: no DIPEA. e: no 1a. Bz = benzyl.
In the next step, the synthetic scope of the method was
investigated (Scheme 1). N-substituted, five membered cyclic
carbamates and ureas were prepared in good to excellent yield
(Fig. 2, 3b-3d). Unsubstituted, five and six membered cyclic
carbamates, carbonates and ureas also showed good to
excellent conversion (3e-3j). More complex carbamate 3k was
isolated in good yield with a diastereomeric ratio of 1:1. 1,2-Cis-
configured carbamate 3l and carbonate 3m were prepared in
moderate to good yield without racemization. Subsequently,
amino acids and amino alcohols were investigated. The ethyl
and benzyl ester of serine (3n and 3o), as well as the methyl
ester of threonine (3p) gave good to excellent yields.
Noteworthily, 3p was obtained diastereomerically pure indicating
that no racemization of the reactive α-position took place. The
methyl ester of cysteine (3q) gave a moderate yield, but
This article is protected by copyright. All rights reserved.

10.1002/chem.201804603
Chemistry - A European Journal
FULL PAPER
Scheme 1. General conditions: A mixture of 0.1 mmol of substrate, 1.05 eq.
of 2b, 2 mol% P3, 3 eq. of DIPEA in neat MeCN (0.1 M) under N2 atmosphere
were irradiated for 24 h with 400 nm light. a: 70% isolated yield on a 7 mmol
(gram)scale. b: 4 eq. of DIPEA were used because the starting material was a
hydrochloride salt. c: DMF (0.1 M) was used as the solvent. Bz = benzyl, Me =
methyl, n-Bu = n-butyl, Et = ethyl.
about the mechanistic investigation). Currently, further transient
spectroscopic investigations on P3 and this catalytic
transformation are ongoing in our lab.
To find evidence for the presence of a benzonitrile radical
originating from a photo-reductive mechanism, we performed
radical trapping experiments in presence of 1a. We observed
48% conversion of 2b to the corresponding N-methylpyrrole
adduct 5a (Fig. 2b). Moreover, the aryl radical could be trapped
with the isolated double bond of allylbenzene giving adduct 5b in
45% yield. The different radical trapping conditions did not
influence the conversion of 1a significantly, as 3a was isolated in
high yields. The formation of 5a and 5b is a good indication for
the intermediacy of an aryl and the operation of a photo-
To investigate the mechanism, transient spectroscopy,
cyclovoltammetry as well as radical trapping experiments and in-
situ and ex-situ NMR analyses were performed. To get insight
into the photocatalytic mechanism, the quenching of the excited
state of P3 was investigated by transient spectroscopy. The
measurements revealed that both, addition of DIPEA (Eox = +0.8
V vs. SCE) and 2b (Ered = -2.1 V vs. SCE) had no influence on
the triplet lifetime of P3 (Eox = +0.4 V; Ered = -1.7 V, see Fig.
S2).14 However, during measurements at catalyst concentrations
of 30 μM and above (compared to 2 mM under the reaction
conditions), we observed a charge-transfer band originating from
the radical cation part in the catalyst CT-complex dimer.15 The
lifetime of this band decreases significantly by addition of DIPEA
(Fig. 2a). This indicates, that the charge recombination might be
slowed down by interaction of the radical cation part of the CT-
complex with DIPEA. As a consequence, the radical anion part
can reduce 2b to restore its uncharged ground state. This
assumption is supported by cyclovoltammetry of P3 revealing a
ground state reduction potential of the P3 radical anion of about
-2.5 V vs. SCE in MeCN (see Fig. S1 and see SI for more data
1
reductive mechanism.16 In-situ H and 19F NMR profiles further
corroborate this mechanistic step monitoring
a
clean
transformation of 2b into 4 upon illumination of P3 in the
presence of DIPEA (see Fig. S16 and S18). Next, an ex situ
NMR profile of the whole reaction with substrate 1a was
recorded (Fig. 2c). Upon illumination, 2b (black) and 1a (violet)
start to decrease, while the two main products 3a (green) and 4
(red) can be readily detected. Furthermore, two more reaction
intermediates could be identified (F-I, magenta and OC-I, cyan).
Instead of the highly reactive free fluorophosgene itself, the
formation of its next downstream more stable reaction
intermediate (F-I) with 1a was observed. Using advanced 1D
1
and 2D NMR techniques for the H, 19F and 13C assignment the
Figure 2. a) Stern-Volmer plot of quenching of the P3 radical cation with DIPEA; inset: comparison of P3 radical cation spectrum obtained via transient
spectroscopy and spectro-electro chemistry (See SI for details). b) Radical trapping experiments with N-methylpyrrole and allylbenzene. c) Ex situ reaction profile
of 1a (100 mM), 2b (105 mM), P3 (2 mM) and DIPEA (300 mM) in CD3CN. Next to the major products 3a (green) and 4 (red), two intermediates can be detected; F-
I (magenta), which is the next downstream intermediate of fluorophosgene and the direct precursor of 3a and OC-I (cyan). OC-I presents an off-cycle intermediate
being in an ongoing water dependent equilibrium with 1a. As long as fluorophosgene is generated, OC-I is slowly converted into 3a through 1a. d) Excerpt of the in
situ reaction profile of 1a (100 mM), 2b (110 mM), P3 (2 mM) and DIPEA (300 mM) in CD3CN showing the initial trend of 3a (green) and F-I (magenta). The
formation of 3a is preceded by an initial lag-phase whilst the intermediate F-I is generated immediately after the light is turned on as the direct precursor of 3a.
This article is protected by copyright. All rights reserved.

10.1002/chem.201804603
Chemistry - A European Journal
FULL PAPER
intermediate was identified as a carbonyl fluoride adduct (F-I) of
1a. The immediate formation of F-I combined with the lag-phase
of 3a in the illuminated in situ NMR profile (Fig. 2d) suggested F-
I as direct precursor of 3a. This is further solidified by the fact
that once the light is turned off, a distinct conversion of F-I into
3a can be observed (for spectra see SI).
based nucleophiles resulting in a carbonylfluoride intermediate
(see F-I).17 Subsequent cyclization leads to the desired product.
To regenerate P3, the P3∙+ oxidizes DIPEA and the aryl radical
abstracts a hydrogen atom from DIPEA∙+ or the solvent to give
benzonitrile. Next to the main pathway, a second off-cycle
pathway is in progress. Downstream reactions of DIPEA lead to
the liberation of acetaldehyde, which can readily react with 1a to
yield the off-cycle intermediate OC-I. The resulting equilibrium of
OC-I and 1 is heavily dependent on the water concentration. As
long as fluorophosgene is provided, OC-I is slowly converted
into 3a through 1a. Addition of extra water can virtually suppress
the off-cycle equilibrium, which in turn accelerates the reaction.
In addition, a second, off-cycle intermediate (OC-I, Fig. 2c) could
be assigned. The emergence of OC-I is the reason for the
evidently faster decrease of 1a with respect to 2b (Fig. 2c), as it
stems from a side reaction of 1a with acetaldehyde, which in
turn is liberated after downstream reactions from DIPEA (see
SI). From the three hour mark on in Fig. 2c, it is evident, that 1a
and F-I are already gone, whilst OC-I is slowly decreasing and
1a is still slowly increasing. This suggests that OC- I and 1a are
in a slow off-cycle equilibrium. It could also be shown that this
equilibrium is heavily water dependent (see SI). This results in
3a still being generated even after 1a is fully consumed as long
as fluorophosgene is still liberated. Furthermore, addition of
water can effectively reduce the formation of OC-I and increase
the reaction rates significantly (See SI for further details on the
NMR analyses). Therefore, we propose the following
mechanism for the liberation of fluorophosgene from 2b (Fig. 3).
P3 is excited by the light of 400 nm LEDs. The two excited
photocatalyst molecules P3* form a CT-complex dimer which
disproportionates to the corresponding P3∙+ and P3∙-. The P3∙-
reduces 2b leading to its fragmentation into the aryl radical and
trifluoromethanolate. Trifluoromethanolate decomposes into F-
and fluorophosgene, which readily reacts with amine- or alcohol-
Conclusions
In summary, we have developed the first, visible light mediated
procedure for the cleavage of an aryl trifluoromethoxy ether and
the controlled liberation and in-situ conversion of fluorophosgene
for the synthesis of carbamates, carbonates and urea
derivatives. The method shows regio-selectivity for aliphatic
amines and/or alcohols in presence of aromatic ones. No
racemization of amino acid stereocenters was observed.
Transient spectroscopy suggests the formation of a catalyst CT-
complex dimer as the catalytic active species. NMR
measurements identified key intermediates consolidating a
stepwise fragmentation into fluorophosgene as the most likely
Figure 3. Proposed catalytic cycle for the photocatalytic liberation of fluorophosgene for substrate 1a, based on the conducted mechanistic studies. The
mechanism can be differentiated into two segments: a: The main reaction, which comprises the photocatalytic liberation of fluorophosgene by reducing 2b and
the subsequent reaction of fluorophosgene with 1a over F-I to yield 3a. b: The off-cycle equilibrium (gray background), which describes the water dependent
equilibrium between 1a and OC-I through addition and cleavage of acetaldehyde (secondary product of DIPEA). Detected products and intermediates are
highlighted.
This article is protected by copyright. All rights reserved.

10.1002/chem.201804603
Chemistry - A European Journal
FULL PAPER
mechanistic pathway; while also uncovering a water dependent
off-cycle equilibrium, which can be effectively modulated to
accelerate the reaction. Notably, this method expands the
toolbox of photoredoxcatalysis by the generation of an extremely
reactive species which is not based on radical reactivity under
mild reaction conditions.
F. Nat. Chem. 2017, 9, 453–456; (c) Studer, A.; Curran, D. P. Nat.
Chem. 2014, 6, 765–773; (d) Hopkinson, M. N.; Tlahuext-Aca, A.;
Glorius, F., Acc. Chem. Res. 2016, 49, 2261–2272.
[9]
(a) Neubauer, A.; Grell, G.; Friedrich, A.; Bokarev, S. I.; Schwarzbach,
P.; Gärtner, F.; Surkus, A.-E.; Junge, H.; Beller, M.; Kühn, O.;
Lochbrunner, S. J. Phys. Chem. Lett. 2014, 5, 1355–1360; (b) Singh,
A.; Fennell, C. J.; Weaver, J. D. Chem. Sci. 2016, 7, 6796–6802; (c) Lu,
Z.; Yoon, T. P. Angew. Chem. Int. Ed. 2012, 51, 10329–10332.
[10] (a) Shaw, M. H.; Twilton, J.; MacMillan, D. W. C. J. Org. Chem. 2016,
81, 6898–6926; (b) Majek, M.; Jacobi von Wangelin, A. Acc. Chem.
Res. 2016, 49, 2316–2327; (c) Petrone, D. A.; Ye, J.; Lautens, M.
Chem. Rev. 2016, 116, 8003–8104.
Acknowledgements
This work was supported by the German Science Foundation
(DFG) (GRK 1626, Chemical Photocatalysis). We thank Dr.
Rudolf Vasold (University of Regensburg) for his assistance in
GC-MS measurements and Regina Hoheisel (University of
Regensburg) for her assistance in cyclic voltammetry
measurements.
[11] (a) Iijima, A.; Amii, H., Tetrahedron Lett. 2008, 49, 6013–6015; (b) Goh,
K. K. K.; Sinha, A.; Fraser, C.; Young, R. D. RSC Adv. 2016, 6, 42708–
42712; (c) Combellas, C., Kanoufi, F., Thiébault A. J. Electroanal.
Chem. 1997, 432, 181–192.
[12] (a) Sahoo, B.; Hopkinson, M. N. Angew. Chem. Int. Ed. 2018, 57,
7942–7944; (b) Togni, A., Jelier, B. J., Tripet, P. F., Pietrasiak, E.,
Franzoni,
I.;
Jeschke,
G.
Angew.
Chem.
Int.
Ed.
10.1002/anie.201806296
Conflict of interest
[13] (a) Pearson, R. M.; Hooi-Lim, C.; McCarthy, B. G.; Musgrave, C. B. J.
Am. Chem. Soc. 2016, 138, 11399−11407; (b) Du, Y.; Pearson, R.;
Hooi-Lim, C.; Sartor, S.; Ryan, M.; Yang, H.; Damrauer, N.; Miyake, G.
Chem. Eur. J., 2017, 23, 10962−10968.
The authors declare no conflict of interest.
[14] McCarthy, B. G.; Pearson, R. M.; Lim, C.-H.; Sartor, S.; Damrauer, N.
H.; Miyake, G. M., J. Am. Chem. Soc. 2018, 140, 5088–5101.
[15] Sartor, S. M., McCarthy, B. G., Pearson, R. M., Miyake, G. M.;
Damrauer, N. H. J. Am. Chem. Soc. 2018, 140, 4778–4781.
[16] Hari, D. P., Schroll, P.; König, B., J. Am. Chem. Soc. 2012, 134, 2958–
2961.
Author contributions
¶: Authors contributed equally to this work. D. P. developed the
project, optimized the reaction, prepared the substrate scope
and the manuscript. P. N. performed the NMR measurements
and evaluations and contributed to the mechanistic part of the
manuscript. F. B. Performed the transient spectroscopy
experiments and evaluations. V. S. assisted with the NMR
measurements. B. D., R. M. G. and B. K. supervised the project
and the preparation of the manuscript.
[17] Nguyen, M.; Matus, M. H.; Ngan, V.; Haiges, R.; Christe, K. O.; Dixon,
D. A. J. Phys. Chem. A 2008, 112, 1298–1312.
Keywords: Photocatalysis • CT-Complex • Fluorophosgene •
NMR-Spectroscopy • Trifluoromethoxyarenes
[1]
[2]
(a) Heravi, M. M.; Zadsirjan, V.; Farajpour, B. RSC Adv. 2016, 6,
30498–30551; (b) Rodrigo, M. A.; Oturan, N.; Oturan, M. A. Chem. Rev.
2014, 114, 8720−8745; (c) Magano, J.; Dunetz, J. R. Chem. Rev. 2011,
111, 2177–2250; (d) Zhou, Y.; Wang, J.; Gu, Z.; Wang, S.; Zhu, W.;
Aceꢀa, J. L.; Soloshonok, V. A.; Izawa, K.; Liu, H. Chem. Rev. 2016,
116, 422−518.
(a) Ghosh, A. K.; Brindisi, M. J. Med. Chem. 2015, 58, 2895−2940; (b)
Parrish, J. P.; Salvatore, R. N.; Jung, K. W. Tetrahedron 2000, 56,
8207–8237; (c) Díaz, D. J.; Darko, A. K.; McElwee-White, L. Eur. J. Org.
Chem. 2007, 4453–4465.
[3]
[4]
Pasquato, L.; Modena, G.; Cotarca, L.; Delogu, P.; Mantovani, S. J. Org.
Chem. 2000, 65, 8224–8228.
(a) W. Schneider, W. Diller in Ullmann’s Encyclopedia of Industrial
Chemistry, Vol. 26, Wiley-VCH: Weinheim, 2000, pp 623−632 (b)
Cotarca, L.; Geller, T.; Répási, J. Org. Process Res. Dev. 2017, 21,
1439−1446.
[5]
[6]
[7]
Sakakura, T.; Kohnoa, K. Chem. Commun. 2009, 1312–1330.
Romero, N. A.; Nicewicz, D. A. Chem. Rev. 2016, 116, 10075–10166.
(a) Petzold, D.; König, B. Adv. Synth. Catal. 2018, 360, 626–630; (b)
Ghosh, I.; Ghosh, T.; Bardagi, J. I.; König, B. Science 2014, 346, 725–
728; (c) Ghosh, I.; König, B., Angew. Chem. Int. Ed. 2016, 55, 7676–
7679; (d) Düsel, S. J. S.; König, B J. Org. Chem. 2018, 83, 7676; (e)
Romero, N. A.; Margrey, K. A.; Tay, N. E.; Nicewicz, D. A. Science
2015, 349, 1326–1330.
[8]
(a) Twilton, J.; Le, C.; Zhang; P. Shaw, M. H.; Evans, R. W.; MacMillan,
D. W. C., Nat. Rev. 2017, 1, 52; (b) Seo, H.; Katcher, M. H.; Jamison, T.
This article is protected by copyright. All rights reserved.

10.1002/chem.201804603
Chemistry - A European Journal
FULL PAPER
FULL PAPER
Fluorophosgene was liberated by the
photocatalytic reduction of a simple
aryltrifluoromethoxyether. This highly
reactive species was used for the
synthesis of cyclic carbonates,
carbamates and urea derivatives. The
reaction mechanism was investigated
by an in-depth NMR study as well as
Daniel Petzold, Philipp Nitschke, Fabian
Brandl, Veronica Scheidler, Bernhard
Dick, Ruth M. Gschwind, Burkhard
König*
1 – 5
Visible Light Mediated Liberation and
in situ Conversion of Fluorophosgene
cyclovoltammetry
and
transient
spectroscopy which suggests
a
charge-transfer complex dimer as the
catalytic active species.
This article is protected by copyright. All rights reserved.