Stable and Storable N(CF3)2 Transfer Reagents

Article abstract of DOI:10.1002/chem.202101436

Fluorinated groups are essential for drug design, agrochemicals, and materials science. The bis(trifluoromethyl)amino group is an example of a stable group that has a high potential. While the number of molecules containing perfluoroalkyl, perfluoroalkoxy, and other fluorinated groups is steadily increasing, examples with the N(CF₃)₂ group are rare. One reason is that transfer reagents are scarce and metal-based storable reagents are unknown. Herein, a set of Cu^I and Ag^I bis(trifluoromethyl)amido complexes stabilized by N- and P-donor ligands with unprecedented stability are presented. The complexes are stable solids that can even be manipulated in air for a short time. They are bis(trifluoromethyl)amination reagents as shown by nucleophilic substitution and Sandmeyer reactions. In addition to a series of benzylbis(trifluoromethyl)amines, 2-bis(trifluoromethyl)amino acetate was obtained, which, upon hydrolysis, gives the fluorinated amino acid N,N-bis(trifluoromethyl)glycine.

Full text of DOI:10.1002/chem.202101436

Accepted Article
Accepted Article
Title: Bis(trifluoromethyl)amido Complexes of Copper and
Silver: Stable and storable N(CF3)2 transfer reagents
Authors: Leon N. Schneider, Eva-Maria Tanzer Krauel, Carl Deutsch,
Klaus Urbahns, Tobias Bischof, Kristina Maibom, Johannes
Landmann, Fabian Keppner, Christoph Kerpen, Michael
Hailmann, Ludwig Zapf, Tanja Knuplez, Rüdiger Bertermann,
Nikolai V. Ignatiev, and Maik Finze
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.202101436
Link to VoR: https://doi.org/10.1002/chem.202101436
01/2020

10.1002/chem.202101436
Chemistry - A European Journal
COMMUNICATION
Bis(trifluoromethyl)amido Copper(I) and Silver(I) Complexes:
Stable and Storable N(CF3)2 Transfer Reagents
Leon N. Schneider, Eva-Maria Tanzer Krauel, Carl Deutsch, Klaus Urbahns, Tobias Bischof, Kristina
Maibom, Johannes Landmann, Fabian Keppner, Christoph Kerpen, Michael Hailmann, Ludwig Zapf,
Tanja Knuplez, Rüdiger Bertermann, Nikolai V. Ignat’ev, and Maik Finze[*]
In memoriam Siegfried Hünig
Abstract: Fluorinated groups are essential for drug design, agroche-
micals, and materials science. The bis(trifluoromethyl)amino group is
an example for a stable group that has a high potential. While the
number of molecules containing perfluoroalkyl, perfluoroalkoxy, and
other fluorinated groups is steadily increasing, examples with the
N(CF3)2 group are rare. One reason is that transfer reagents are
scarce and metal-based storable reagents are unknown. Here, we
present a set of CuI and AgI bis(trifluoromethyl)amido complexes
stabilized by N- and P-donor ligands with unprecedented stability. The
complexes are stable solids that can even be manipulated in air for a
short time. They are bis(trifluoromethyl)amination reagents as shown
by nucleophilic substitution and Sandmeyer reactions. In addition to a
series of benzylbis(trifluoromethyl)amines, 2-bis(trifluoromethyl)-
amino acetate was obtained that upon hydrolysis gives the fluorinated
amino acid N,N-bis(trifluoromethyl)glycine.
Transition metal perfluoroalkyl complexes are highly valuable
reagents for the synthesis of fluorinated biologically active
molecules that are employed as pharmaceuticals or agrochemi-
cals and in materials applications.[1-6] Especially, copper(I) com-
Figure 1. Comparison of the availability of CuI and AgI complexes (top), two-
plexes are important as they enable the introduction of a broad
step synthesis of salts of the N(CF3)2– ion via electrochemical fluorination (ECF)
–
of CF3SO2N(CH3)2 (middle),[16-17] and decomposition sequence of the N(CF3)2
variety of perfluoroalkyl groups into organic molecules that range
from the simplest congener, trifluoromethyl, to longer linear and
branched perfluoroalkyl groups such as the heptafluoroisopropyl
(hfip) group.[7-10] Although many of these complexes are used
either in situ or immediately after generation, some complexes
have been isolated and characterized, in detail. These complexes
are often stabilized by co-ligands that typically are pyridines or
phosphanes, for example [(bpy)CuC2F5] (Figure 1)[11] and
[(Ph3P)2Cu{CF(CF3)2}] ([(Ph3P)2Cu(hfip)]).[12] Silver(I) complexes
have been employed as perfluoroalkylation reagents as well,[13-14]
although to a lesser extent than the related copper(I) derivatives.
Because of their easy accessibility using silver(I) fluoride and the
respective perfluoroalkene, e.g. heptafluoropropene and tetraflu-
oroethylene,[15] they are of increasing interest. Similarly, copper(I)
ion via perfluoroazapropene to result in CF3N=CF–N(CF3)2.[18]
and silver(I) complexes with perfluorinated ligands that are coor-
dinated via oxygen, sulfur, or selenium to the coinage metal have
recently come into focus and have been established as transfer
reagents for perfluorinated groups, e.g. for trifluoromethoxyla-
tion,[19-20] trifluoromethylthiolation,[21-22] and trifluoromethylseleno-
lation reactions.[23-24] So far, only few CuI and AgI metal complexes
with the trifluoromethoxy ligand like [(PhtBu2P)(bpy)AgOCF3][25]
are known (Figure 1).[25-27] The small number of structurally
–
characterized complexes is due to the low stability of the OCF3
ion that easily loses F– while releasing carbonyl fluoride (difluoro-
phosgene), which enabled the use of AgOCF3 as C(O)F2
source.[28] This synthetic useful reaction is similar to the decom-
position of perfluoroalkyl ions into perfluoroalkenes and fluoride,
for example the generation of tetrafluoroethylene from the penta-
fluoroethyl ion.
[*] L. N. Schneider, T. Bischof, K. Maibom, Dr. J. Landmann, Dr. F.
Keppner, Dr. C. Kerpen, Dr. M. Hailmann, L. Zapf, T. Knuplez, Dr. R.
Bertermann, Dr. N. V. Ignat’ev, and Prof. Dr. M. Finze
Institut für nachhaltige Chemie & Katalyse mit Bor (ICB)
Institut für Anorganische Chemie
In contrast to perfluoroalkyl and perfluoroalkoxy groups, the
chemistry of related perfluoroalkyl nitrogen substituents has been
studied to a much lesser extent. Some synthetic strategies
towards N-trifluoromethylamines and related N-perfluoroalkyl-
nitrogen derivates have been developed in recent years.[28-38]
Efficient strategies towards N,N-bis(perfluoroalkyl)nitrogen com-
pounds remain scarce, presumably, because of the lack of suitab-
le starting materials.[18,39-40] Especially the N,N-bis(trifluoro-
methyl)amino group is of interest since its organic derivatives are
known to exhibit high stability, e.g. against acids and bases,[1,41]
Julius-Maximilians-Universität Würzburg
Am Hubland, 97074 Würzburg (Germany)
E-mail: maik.finze@uni-wuerzburg.de
Web: http://go.uniwue.de/finze-group
Dr. Eva-Maria Tanzer Krauel, Dr. Carl Deutsch, Dr. Klaus Urbahns
Merck Healthcare KGaA, Darmstadt (Germany)
Dr. Eva-Maria Tanzer
Insitro Inc., South San Francisco, CA, USA
1
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10.1002/chem.202101436
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Figure 2. Synthesis and crystal structures of the copper(I) complexes 1a–1e (thermal ellipsoids set at 25% probability; H atoms are omitted for clarity; C atoms of
the N- and P-donor ligands are depicted as stick models).
and because its potential as substituent in pharmaceuticals was
demonstrated, earlier.[42-43] N,N-Bis(trifluoromethyl)amino deriva-
tives have been obtained from perfluoroazapropene CF3N=CF2
as initial starting compound or via tedious reaction sequen-
ces.[18,39,44] Perfluoroazapropene is accessible via laborious multi-
step syntheses only,[45-47] it is a reactive gas that requires special
equipment for handling, and its transformation into the
[Cu(bpy)2][CuCl2] was either isolated and redissolved or prepared
in situ from copper(I) chloride and 2,2’-bipyridine giving almost
equal yields for 1a of 83 and 82%, respectively. Alternatively,
Cu{N(CF3)2} was synthesized from CuCl and Rb{N(CF3)2} in
acetonitrile, and 2,2’-bipyridine was added to give 1a in 41% yield
(Figure 2). Because of the lower yield, all further copper(I)
bis(trifluoromethyl)amido complexes were synthesized from
preformed copper(I) complexes and Rb{N(CF3)2} or Cs{N(CF3)2}.
In addition to 1a, the analogous dark orange 1,10-phenanthroline
(phen) complex [(phen)Cu{N(CF3)2}] (1d) was isolated in 90%
yield. The colorless triphenylphosphane complex [(Ph3P)2Cu-
{N(CF3)2}] (1b) that was obtained in almost quantitative yield
represents the third complex with a tricoordinate copper center. In
contrast, the yellow-orange mixed complexes [(bpy)(Ph3P)Cu-
{N(CF3)2}] (1c) and [(phen)(Ph3P)Cu{N(CF3)2}] (1e) that were iso-
lated in 77 and 79% yield, respectively, contain four coordinate
CuI centers (Figure 2).
Acetonitrile solutions of the silver(I) salt Ag{N(CF3)2} obtain-
ed from silver(I) fluoride and CF3SO2N(CF3)2 (Figure 1) were used
for the synthesis of silver(I) bis(trifluoromethyl)amido complexes
(Figure 3). In analogy to the copper(I) N(CF3)2 derivatives, three-
and four-coordinate AgI complexes were obtained. The three
colorless complexes [(bpy)Ag{N(CF3)2}] (2a), [(Ph3P)2Ag-
{N(CF3)2}] (2b), and [(bpy)(Ph3P)Ag{N(CF3)2}] (2c) were isolated
in yields of 78, 89, and 90%, respectively. The 2,2’:6’,2’’-
terpyridine (terpy) derivative [(terpy)Ag{N(CF3)2}] (2f) was
obtained as a yellow crystalline material in 62% yield.
–
synthetically useful bis(trifluoromethyl)amide ion N(CF3)2 is
usually accompanied by dimerization giving CF3N=CF–N(CF3)2
(Figure 1). N,N-bis(trifluoromethyl)trifluoromethanesulfonimide
CF3SO2N(CF3)2 is accessible via electrochemical fluorination
(ECF) of CF3SO2N(CH3)2 in anhydrous hydrogen fluoride (aHF)
according to the Simons process on large scale.[16,44,48]
CF3SO2N(CF3)2 reacts with fluorides such as silver(I) and
–
rubidium fluoride providing a convenient access to the N(CF3)2
ion (Fig. 1).[17,49] Some N,N-bis(trifluoromethyl)amides with
organic cations are stable whereas metal salts can only be
handled in solution to prevent decomposition. Few of these
organic salts have been used in metatheses[49-52] or for the
synthesis of organic molecules with the N(CF3)2 group.[39-40,53-54]
So far, mercury complexes, e.g. [Hg{N(CF3)2}2], are the sole
stable metal complexes with the N(CF3)2 ligand, known.[55] The
salts M{N(CF3)2·NCCH3 (M = Ag, Cu) have been described as
white solids.[49] However, these salts cannot be stored because
they immediately start to decompose, even at low temperature.[56]
So, they are no convenient, storable N(CF3)2 transfer reagents.
Herein, we present a set of stable and storable copper(I)
and silver(I) complexes of the bis(trifluoromethyl)amido ligand.
These complexes have been found to be promising compounds
for the transfer of the bis(trifluoromethyl)amino group into organic
molecules.
The silver(I) triphenylphosphane complex 2b reacts with
additional triphenylphosphane under formation of the complex
salt [Ag(PPh3)4]{N(CF3)2} (3) that is composed of the tetrahedral
[Ag(PPh3)4]+ cation and a non-coordinated {N(CF3)2}– anion. Salt
Copper(I) complexes with the N(CF3)2 ligand have been
synthesized via metatheses using CH3CN solutions of rubidium or
cesium bis(trifluoromethyl)amide that were generated from
CF3SO2N(CF3)2 and the respective dry alkali metal fluoride (Figu-
re 2). The dark orange complex [(bpy)Cu{N(CF3)2}] (1a, bpy =
2,2’-bipyridine) was prepared from a solution of Rb{N(CF3)2} in
acetonitrile and [Cu(bpy)2][CuCl2]. The copper(I) derivative
3 was selectively prepared from triphenylphosphane and
Ag{N(CF3)2} in 60% yield and characterized, in detail (Figure 3).
In contrast to [(Ph3P)2Ag{N(CF3)2}] (2b), the respective copper(I)
complex [(Ph3P)2Cu{N(CF3)2}] (1b) does not react with an excess
of triphenylphosphane to result in a complex salt and 1b was
obtained even in the presence of a twofold excess of PPh3 in 78%
yield.
2
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Figure 3. Synthesis and crystal structures of the silver(I) complexes 2a–2c, 2f and of the complex silver(I) salt 3 (thermal ellipsoids set at 25% probability; H atoms
are omitted for clarity; C atoms of the N- and P-donor ligands are depicted as stick models).
The copper(I) and silver(I) bis(trifluoromethyl)amido complexes
are thermally stable with decomposition temperatures ranging
from 114 to 204 °C (onset, DSC measurements). The solid com-
plexes can be stored in a glove box in an inert atmosphere for
more than one year without noticeable decomposition and they
can be manipulated in air for a short period of time enabling a
convenient handling.
solid state NMR spectra of 3 and 2b also reveal the different
bonding situations in the two related silver(I) bis(trifluoro-
methyl)amido complexes. Especially, the smaller 1J(107/109Ag,31P)
coupling constants observed for 3 are indicative for a four-
1
coordinate complex whereas larger J(107/109Ag,31P) hint towards
a three-coordinate silver complex in case of 2b (Figure S18 in the
Supporting Information).[58]
The coordination of the bis(trifluoromethyl)amido ligand to
copper in 1a–1e and to silver in 2a–2c and 2f in the solid state is
evident from single-crystal X-ray diffraction (SC-XRD) analyses,
which are the first examples for SC-XRD studies on N(CF3)2 coor-
dination compounds (Figures 2 and 3 and Table S5 in the
Supporting Information). The metal–nitrogen distances depend
on the coordination number of the metal center. So, d(Cu–
The bis(triphenylphosphane) complexes 1b and 2b were
studied by diffusion-ordered spectroscopy (DOSY) in CD3CN and
CD2Cl2 (Table S7 in the Supporting Information). The diffusion
1
constants derived from the H and 19F NMR measurements on
samples dissolved in CD2Cl2 are very similar. The hydrodynamic
radii of 1b (1H-DOSY: 6.15 Å; 19F-DOSY: 5.97 Å) and 2b (1H-
DOSY: 6.16 Å; 19F-DOSY: 6.00 Å) calculated from diffusion
N(CF3)2) is 1.900(9)–2.004(8) Å in the tricoordinate complexes 1a, constants using a modified Stokes-Einstein equation, are close to
1b, and 1d but 2.0654(16) and 2.101(2) Å in four-coordinate 1c
and 1e, respectively. As expected from the slightly smaller
covalent radius of copper (1.32 Å for Cu vs. 1.45 Å for Ag),[57] the
metal–N(CF3)2 distance is longer in the silver(I) complexes with
2.138(2) and 2.255(4) Å for tricoordinate complexes 2a and 2b
and 2.330(5) and 2.233(3) Å for the four-coordinate derivatives 2c
and 2f. The crystal structure of 3 proves the ionic nature of the
complex salt (Figure 3). The N(CF3)2– ion, which was until now not
characterized by SC-XRD, at all, is disordered over two positions
precluding a detailed discussion of bonding parameters.
radii estimated from the crystal structures (1b: 5.07 Å; 2b: 5.08 Å;
see Supporting Information for a detailed description). Thus, it can
be concluded that 1b and 2b remain intact in CD2Cl2. In contrast,
in CD3CN the diffusion constants derived from the 1H NMR signals
–
of the PPh3 ligands and from the 19F NMR signal of the N(CF3)2
ligand are significantly different. However, the diffusion constant
of the unbound N(CF3)2– ion (Dt(19F) = 24.04·10–10 m2 s–1) derived
from a DOSY study on 3 in CD3CN is much larger than Dt(19F)
measured for 1b (17.48·10–10 m2 s–1) and 2b (14.65·10–10 m2 s–1)
in the same solvent. These data indicate an equilibrium between
coordinated and free N(CF3)2– in solutions of 1b and 2b in CD3CN
as Dt(19F) is an averaged value since M–N(CF3)2 bond formation
and dissociation is too fast to be resolved on the NMR time scale.
Similar to 1b and 2b, the bipyridine complexes 1a and 2a reveal
partial dissociation into ions in CD3CN solution, as well.
The novel thermally robust bis(trifluoromethyl)amido
copper(I) and silver(I) complexes were used for the introduction
of the N(CF3)2 group into organic molecules. The reactions
studied, so far, are (i) nucleophilic substitutions giving a set of
benzylbis(trifluoromethyl)amines (4–6), 2-bis(trifluoromethyl)-
aminomethylnaphthalene (7), 2-bis(trifluoromethyl)amino acetate
(8a), and (ii) a Sandmeyer reaction leading to 1-fluoro-4-
bis(trifluoromethyl)aminobenzene (9).
All copper(I) and silver(I) N(CF3)2 derivatives were charac-
terized by multinuclear NMR, IR, and Raman spectroscopy, as
well as by elemental analysis. The 19F NMR signal of the comple-
xes is in the range from –40.7 to –43.7 ppm, which is similar to
d(19F) of Ag{N(CF3)2} and Cu{N(CF3)2} in CD3CN with –42.1 and
–43.4 ppm, respectively. The signal of Rb{N(CF3)2} in CD3CN is
observed at a significantly lower chemical shift of –37.5 ppm
(Figure S17 in the Supporting Information). Thus, the interaction
between the coinage metal and the N(CF3)2– ligand in solution is
evident from the 19F NMR spectroscopic data. The signal of the
complex salt [Ag(PPh3)4]{N(CF3)2} (3) in CD2Cl2 is observed at
–39.6 ppm, which, in turn, is indicative for the ionic nature that
was proven by the SC-XRD study. Solid state 19F NMR spectra
reveal an even more pronounced difference for diso(19F) with –31.6
and –34.6 ppm for the salt 3 and –40.4 and –41.4 ppm for the
complexes [(Ph3P)2Ag{N(CF3)2}] (2b) and [(Ph3P)2Cu{N(CF3)2}]
The four benzylbis(trifluoromethyl)amines 4–6 and the
naphthalene derivative 7 were isolated in yields of 56–65% using
the 2,2’-bipyridine and 1,10-phenanthroline complexes 1a, 2a, or
1d as starting materials (Figure 4). The synthesis of the parent
(1b) (Figure S19 in the Supporting Information). The 31P and 13
C
3
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Figure 5. Synthesis of 2-bis(trifluoromethyl)amino acetate (8a), its conversion
into N,N-bis(trifluoromethyl)glycine (8b), and the crystal structure of 8b (thermal
ellipsoids set at 30% probability; H atoms are omitted for clarity).
Table 1: Reactivity screening of copper(I) and silver(I) bis-
(trifluoromethyl)amido complexes with ethyl bromoacetate to give 2-
bis(trifluoromethyl)amino acetate (8a).[a]
O
O
+ [LM{N(CF3)2}]
Br
(CF3)2N
O
CH3CN
O
1 eq
1eq
80 °C, over night
8a
Entry
Complex
Yield (%)
1
[(bpy)Cu{N(CF3)2}]
(1a)
75
74
33
39
8
2
3
4
5
6
7
8
[(phen)Cu{N(CF3)2}]
[(bpy)(Ph3P)Cu{N(CF3)2}]
[(phen)(Ph3P)Cu{N(CF3)2}]
[(Ph3P)2Cu{N(CF3)2}]
[(bpy)Ag{N(CF3)2}]
(1d)
(1c)
(1e)
(1b)
(2a)
(2c)
(2b)
54
28
7
[(bpy)(Ph3P)Ag{N(CF3)2}]
[(Ph3P)2Ag{N(CF3)2}]
Figure 4. Synthesis of bis(trifluoromethyl)methyl arenes and crystal structures
of 5 and 7.
[a] The reactions were performed in Young NMR tubes and monitored
by 19F NMR spectroscopy using equimolar amounts of the coinage
metal(I) complex and ethyl bromoacetate. The internal yields were
determined with benzotrifluoride as standard.
benzylbis(trifluoromethyl)amine 4 was reported using freshly pre-
pared solutions of rubidium or cesium bis(trifluoromethyl)-
amide.[17,59] Compounds 4 and 6 are liquids, whereas the para-
cyano derivative 5 and the naphthalene compound 7 are solids.
The four related compounds 4–7 are air and water stable and no
decomposition was observed during work-up or storage. Crystals
of 5 and 7 were studied by SC-XRD. The N–CF3 distances in 5
(1.399(5) Å) and 7 (1.409(3) Å) are longer than in the coinage
metal(I) complexes (ca. 1.35 Å).
1a and 1d were identified as most efficient reagents with internal
yields of 74 and 75%, respectively. The related silver(I) complex
2a gave ester 8a in significantly lower yield of 54%. Triphenyl-
phosphane complexes are less efficient N(CF3)2 transfer reagents
and the amount of 8a formed, dropped with increasing number of
PPh3 ligands at copper(I) or silver(I). The lower yields were
accompanied with an increasing amount of side products. A major
The reaction of 2-(bromomethyl)naphthalene with [(bpy)-
Cu{N(CF3)2}] (1a) was screened in acetonitrile, dichloromethane,
N,N-dimethylacetamide (DMAC), toluene, pyridine, and THF. The
highest yield for 7 was observed in CD3CN. In dichloromethane
and DMAC significantly lower yields were obtained and in toluene,
side product was identified as Ph3PF2 that was confirmed by 19
F
and 31P NMR spectroscopy in the reaction mixtures. Most of the
phosphorane formed crystallized from the CD3CN solutions upon
cooling to room temperature and a single crystal of Ph3PF2 was
characterized by X-ray diffraction (Figure S16 in the Supporting
Information).
pyridine, and THF almost no conversion to 7 was observed by 19
F
NMR spectroscopy (Table S1 in the Supporting Information).
2-Bis(trifluoromethyl)amino acetate (8a) was isolated in
56% yield (Figure 5). Its conversion into ethyl N,N-bis(trifluoro-
methyl)glycine (8b) was described, earlier.[39] The synthesis of 8b
was repeated and the fluorinated amino acid was characterized
by SC-XRD for the first time. Two formula units of 8b form dimers
in the solid state via a cyclic H-bond motif with d(O···O’) =
2.679(3) Å that are located on a center of inversion (Figure 5).
The conversion of ethyl bromoacetate into 8a using different
copper(I) and silver(I) bis(trifluoromethyl)amido complexes was
monitored by 19F NMR spectroscopy in CD3CN using benzotri-
fluoride as internal reference (Table 1). Especially, the complexes
with 2,2’-bipyridine and 1,10-phenanthroline were found to be
efficient N(CF3)2 transfer reagents and the copper(I) complexes
The lower yield of ester 8a starting from [(bpy)Ag{N(CF3)2}]
(2a) compared to [(bpy)Cu{N(CF3)2}] (1a) (Table 1), tempted us to
perform
a comparative study on nucleophilic substitution
reactions using complexes 1a and 2a (Table S2 in the Supporting
Information). Similar to the syntheses of 8a, lower yields were
observed for reactions using the silver(I) complex 2a. The
reactions studied include the synthesis of benzylbis(trifluoro-
methyl)amine 4 starting from benzylbromide and benzyliodide as
well as the formation of 7 starting from the respective bromide.
Furthermore, the conversion of allylbromide into allylbis-
(trifluoromethyl)amine (10) showed a much lower yield for
(CF3)2NCH2CH=CH2 (10) in case of the reaction from 2a (38%)
compared to 1a (75%).
The further potential of the coinage metal(I) complexes as
bis(trifluoromethyl)amination reagents was demonstrated by the
conversion of 4-fluorobenzenediazonium tetrafluoroborate into 1-
fluoro-4-bis(trifluoromethyl)aminobenzene (9) with [(bpy)Cu-
{N(CF3)2}] (1a) in 34% yield as assessed by 19F NMR spectrosco-
py (Scheme 1). An analogous Sandmeyer reaction resulting in 9
was reported in the literature[40] starting from the corresponding 4-
fluorobenzenediazonium
bis(trifluoromethyl)amide
and
a
copper(I) salt with a yield of 43%.[51] However, the preformation of
4
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5
This article is protected by copyright. All rights reserved.

10.1002/chem.202101436
Chemistry - A European Journal
COMMUNICATION
Entry for the Table of Contents
COMMUNICATION
Leon N. Schneider, Eva-Maria Tanzer
Krauel, Carl Deutsch, Klaus Urbahns,
Tobias Bischof, Kristina Maibom,
Johannes Landmann, Fabian Keppner,
Christoph Kerpen, Michael Hailmann,
Ludwig Zapf, Tanja Knuplez, Rüdiger
Bertermann, Nikolai V. Ignat’ev, and
Maik Finze*
Copper(I) and silver(I) complexes with the bis(trifluoromethyl)amido ligand have
become accessible that are stabilized by pyridine and phosphane ligands. These
complexes are thermally stable and can be stored under inert conditions, which is in
contrast to the behavior of other metal salts including M{N(CF3)2} (M = Cu, Ag). The
complexes were found to be convenient reagents for nucleophilic substitution and
Sandmeyer reactions providing access to a series of organic substrates with the
bis(trifluoromethyl)amino group.
Page No. – Page No.
Bis(trifluoromethyl)amido Copper(I)
and Silver(I) Complexes:
Stable and Storable N(CF3)2 Transfer
Reagents
6
This article is protected by copyright. All rights reserved.