Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

Article abstract of DOI:10.3762/bjoc.15.239

The bis-ortho-thioether 9,10-bis[(o-methylthio)phenyl]anthracene was synthesized as a syn-atropisomer, as revealed by X-ray diffraction. This alkylaryl thioether ligand (L) formed different macrocyclic complexes by coordination with silver(I) salts depending on the nature of the anion: M₂L₂ for AgOTf and AgOTFA, M₆L₄ for AgNO₃. A discrete M₂L complex was obtained in the presence of bulky PPh₃AgOTf. These silver(I) complexes adopted similar structures in solution and in the solid state. As each sulfur atom in the ligand is prochiral, macrocycles L₂M₂ were obtained as mixtures of diastereoisomers, depending on the configurations of the sulfur atoms coordinated to silver cations. The X-ray structures of the two L₂·(AgOTf)₂ stereoisomers highlighted their different geometry. The catalytic activity of all silver(I) complexes was effective under homogeneous conditions in two tandem addition/cycloisomerization of alkynes using 0.5-1 mol % of catalytic loading.

Full text of DOI:10.3762/bjoc.15.239

Self-assembled coordination thioether silver(I) macrocyclic
complexes for homogeneous catalysis
Zhen Cao, Aline Lacoudre, Cybille Rossy and Brigitte Bibal*
Full Research Paper
Open Access
Address:
Beilstein J. Org. Chem. 2019, 15, 2465–2472.
Université de Bordeaux, Institut des Sciences Moléculaires, UMR
CNRS 5255, 351 cours de la libération, 33405 Talence, France
doi:10.3762/bjoc.15.239
Received: 06 May 2019
Email:
Accepted: 20 September 2019
Published: 17 October 2019
Brigitte Bibal* - brigitte.bibal@u-bordeaux.fr
* Corresponding author
Associate Editor: M. Rueping
Keywords:
© 2019 Cao et al.; licensee Beilstein-Institut.
License and terms: see end of document.
coordination macrocycle; homogeneous catalysis; prochiral; silver
complex; thioether ligand
Abstract
The bis-ortho-thioether 9,10-bis[(o-methylthio)phenyl]anthracene was synthesized as a syn-atropisomer, as revealed by X-ray
diffraction. This alkylaryl thioether ligand (L) formed different macrocyclic complexes by coordination with silver(I) salts
depending on the nature of the anion: M2L2 for AgOTf and AgOTFA, M6L4 for AgNO3. A discrete M2L complex was obtained in
the presence of bulky PPh3AgOTf. These silver(I) complexes adopted similar structures in solution and in the solid state. As each
sulfur atom in the ligand is prochiral, macrocycles L2M2 were obtained as mixtures of diastereoisomers, depending on the configu-
rations of the sulfur atoms coordinated to silver cations. The X-ray structures of the two L2·(AgOTf)2 stereoisomers highlighted
their different geometry. The catalytic activity of all silver(I) complexes was effective under homogeneous conditions in two
tandem addition/cycloisomerization of alkynes using 0.5–1 mol % of catalytic loading.
Introduction
Since the early advances in the late eighties [1-10], silver(I) ca- plexes were prepared by using (bi)pyridine [19,23-26], phos-
talysis has been widely exploited based on the versatile redox phine [22,27-30], ditopic N/P [22] ligands and a few S/P and
and soft Lewis acid properties of this coinage metal cation. S/N ones [31-34]. None of the silver(I) catalysts based on sulfur
Silver catalysis has proved its effectiveness for numerous trans- ligands were reported so far, although alkyl thioethers are soft
formations involving unsaturated bond activation (allene, σ-donor ligands such as crown thioethers that were largely de-
alkyne, alkene) [11-17], radical-based reactions [18-20] and veloped as macrocyclic ligands for silver(I) [35-43]. Interest-
several applications in asymmetric reactions [21,22].
ingly, depending on their design, these known silver(I) com-
plexes can be discrete species [35-38], coordination driven
This successful chemistry was usually conducted in the pres- supramolecules [35,42] or coordination polymers [39,40,42].
ence of commercially available inexpensive salts (AgOTf, To the best of our knowledge, silver crown thioether com-
AgNO3) and eventually a (chiral) ligand. Such silver(I) com- plexes were never reported as catalysts.
2465

Beilstein J. Org. Chem. 2019, 15, 2465–2472.
Recently, we described a flexible bis-dialkyl thioether ligand AgOTf for 1a, AgOTFA for 1b, AgNO3 for 1c and PPh3AgOTf
for gold(III) chloride whose photoreduction to gold(I) was fast for 1d.
and controlled [44,45]. These gold complexes at different oxi-
dation states showed efficient catalytic properties, that were
Crystallographic structures of silver
highlighted in a one-pot cascade synthesis of 4H-benzoquino- complexes
lizin-4-one. Now, we propose to investigate a rigid bis-alkyl- Single crystals of 1a, 1c and 1d suitable for X-ray diffraction
aryl thioether ligand to control the directionality and spatial ori- analysis were grown from the slow diffusion of hexane into a
entation of its coordination to silver(I). Besides, 9,10-diphenyl- solution of each complex in dichloromethane. Interestingly,
anthracenes (DPA) with ortho-substituted 9- and 10-aryl groups each prochiral sulfur atom of the ligand becomes asymmetric by
can exist as syn- or anti-atropisomers whose rotational barrier coordination to silver(I). In absence of any chiral source, the
[46,47] ranges from 21 (ortho-H) to 25–29 kcal/mol (ortho- complexes were obtained either as nonchiral coordination prod-
CH3). A few ortho-substituted DPA atropisomers have been de- ucts with a center or an axis of symmetry (1a and 1c, with
scribed as potent molecular switches [48,49], building-blocks (R,S)–1 ligands) or as a racemic mixture (1d, with (R,R)–1 or
for self-assembled capsules [50,51] or optical materials [52-54]. (S,S)–1 ligands).
However, due to their partially frozen structure, syn-isomers of
DPA are ideal candidates for directional metal coordination. The X-ray diffraction of monocrystals 1a revealed the forma-
Herein, a new syn-atropisomer of 9,10-DPA ortho-substituted tion of (R,S–1)2·(AgOTf)2 macrocycles driven by silver(I) coor-
by two thioethers is exploited as a ligand for silver(I) salts. The dination (Figure 1). The two ligands are facing through the
impact of this bis-thioether ligand on silver(I) homogeneous ca- coordination of one syn-thioether group to the same silver
talysis is evaluated in two tandem addition/cycloisomerization cation. Two different crystals were isolated and highlighted the
reactions of alkynes.
two possible arrangements of the ligands that led to different
diastereoisomeric macrocycles (Figure 1a,b). In Figure 1a, each
silver cation was coordinated to two sulfur atoms with the same
configuration (named head-to-head coordination mode for
Results and Discussion
Synthesis of silver(I) complexes
Ligand 1 was synthesized in one step, from commercially avail- ligands) meanwhile in Figure 1b, each Ag(I) cation was coordi-
able 9,10-dibromoanthracene and 2-(methylthio)phenylboronic nated to two sulfur atoms with (R)- and (S)-configuration, re-
acid, using a Suzuki–Miyaura cross-coupling reaction. Notably, spectively (head-to-tail ligand coordination mode). These dia-
the yield was low (26%) [55], and the X-ray analysis of stereoisomeric crystals presented a slightly different spatial
monocrystals revealed the syn-conformation of 1 (Scheme 1). A arrangement.
variable temperature 1H NMR (VT-NMR, Figures S10–12 in
Supporting Information File 1) experiment conducted on syn-1 The head-to head macrocycle 1a had a parallelepiped shape
in the range of –30 to 110 °C in C2D2Cl4 showed the broad- (Figure 1a): the interplanar distance between two anthracenes
ening of proton signals, due to the restricted rotation of the was ca. 6.31 Å and the dihedral angle between the anthracene
9,10-aryl substituents in respect to the anthracene core, without core and its 9,10-aryl substituents was 89° and 104°, respective-
any indication of a syn-to-anti isomerization.
ly. The head-to-tail macrocycle 1a adopted a V-shape
(Figure 1b): the angle between the planes of the two
Four silver(I) complexes 1a–d were prepared in excellent anthracenes was 73.2° and the dihedral angles between the aryl
yield (77–92%) by mixing the ligand and the following silver substituents and the anthracene plane ranged between 77° and
salts in a 1:1 ratio in dichloromethane at room temperature: 87°, respectively.
Scheme 1: Synthesis of ligand 1, as its syn-atropisomer.
2466

Beilstein J. Org. Chem. 2019, 15, 2465–2472.
Figure 1: X-ray structures of complex 1a, as two diastereoisomeric macrocycles (R,S-1)2·(AgOTf)2 with ligands assembled in: (a) a head-to-head
fashion and, (b) a head-to-tail mode. Hydrogen atoms are omitted for clarity.
In solution, the two diastereoisomeric macrocycles coexisted,
possibly in different ratios as the chemical shift of protons on
the 9,10-phenyl and anthracene moieties were found slightly
different for three different batches of silver complexes pre-
pared by the same procedure (see Supporting Information
File 1, Figure S9).
The complex formed with AgNO3 had a different stoichiome-
try, due to the multidentate nitrate anions. The X-ray structure
of 1c appeared as a large (R,S-1)4·(AgNO3)6 complex with
three nitrate anions as coordinating bridges between the two
symmetric M3L2 units (Figure 2). The resulting coordinated
macrocycle M6L4 had a globular shape that displayed the
polyaromatic ligands towards the exterior and fully encapsu-
lated two nitrate anions and the silver(I) cations. This silver
nitrate complex was thus soluble in chlorinated solvents.
In the presence of the bulky triphenylphosphine silver triflate
salt, a monocoordination occurred between Ag(I) and each
sulfur atom of ligand 1 leading to a discrete complex (syn-
1)·(Ph3PAgOTf)2, as revealed by 1H NMR and X-ray
(Figure 3). The steric hindrance also induced the access to a
racemic mixture of (R,R)- and (S,S)-complexes where triphenyl-
phosphine groups were located at the opposite sides of the
anthracene core.
Figure 2: X-ray structure of complex 1c, as a (R,S-1)4·(AgNO3)6 cage
with three nitrate anions as coordinating bridges. Hydrogen atoms are
omitted for clarity.
anion induced the formation of a large globular macrocycle
M6L4. A bulkier silver salt favored a mono-coordination on
each binding site.
The crystallographic structures of 1a, 1c and 1d showed that
both ligand syn-1 and the nature of silver anion impacted on the Silver(I) complexes in solution
stoichiometry of coordination complexes. Atropisomer 1 Surprisingly, several batches of each complex 1a–d were com-
directed the self-assembly towards the same half-space pared by 1H NMR (CDCl3, 2 mM) (see Supporting Informa-
(regarding the anthracene core). The triflate anion lead to a tion File 1, Figure S9) and revealed slight variations in the
[2 + 2] macrocycle meanwhile the more coordinating nitrate chemical shifts that might originate from the presence of several
2467

Beilstein J. Org. Chem. 2019, 15, 2465–2472.
ences observed on 1H NMR spectra at 60 °C accounted for a
slight change in the geometry of the complexes probably due to
the thermal motion, and not to the dissociation of self-aggre-
gates. In the temperature range of –30 to 60 °C, none dissociat-
ed free ligand was observed, thus confirming that coordinated
macrocycles 1a–c were thermally stable. At room temperature,
the slight different 1H NMR spectra may account for the exis-
tence of several conformations for these constrained coordinat-
ed architectures, which still have a certain degree of freedom,
that is required for further catalytic properties.
Diffusion-ordered spectroscopy (DOSY) 1H NMR was also
used on complexes 1a–d (5 mM) in CDCl3 (Supporting Infor-
mation File 1, Table S7). Each complex appeared as a unique
species whose diffusion coefficient (D) can be fitted. So the
presence of species with different coordination modes can be
excluded. Unexpectedly, the diffusion constants of both com-
plexes 1a and 1b were disparate (0.6–1.9 × 10−9 m2/s)
Figure 3: X-ray structure of complex 1d, as a racemic mixture of
(R,R)- and (S,S)-(syn-1)·(PPh3AgOTf)2.
species in solution, such as self-aggregates, mixture of depending on the batches meanwhile the D values of com-
conformers, mixture of diastereoisomers or complexes with dif- plexes 1c and 1d at 5 mM were similar (0.80–0.93 × 10−9 m2/s)
ferent stoichiometry.
and not depending on the batch. The nonreproducibility of
DOSY experiments for 1a and 1b might originate from the
To investigate the possible self-aggregation of complexes 1a–c uncontrolled formation of different diastereoisomers by coordi-
(7 mM), VT NMR experiments were conducted between nation which had different geometries. Thereafter, the silver(I)
–30 °C and 60 °C in CDCl3. For complex 1a, the aromatic complexes are discussed with the proposed stoichiometry from
protons were shifted for 0.1 to 0.2 ppm meanwhile the methyl X-ray and NMR data, without accounting for stereochemistry:
of the thioether group was shifted for 0.12 ppm (Figure 4). The M2L2 for AgOTf and AgOTFA complexes (1a,b), M6L4 for
two most affected aromatic protons were located on the 9,10- AgNO3 one (1c) and M2L complex with PPh3AgOTf (1d).
substituents, the one adjacent to SMe group (H1) and the one
closest to the anthracene core (H4). Similar changes on VT Finally, the photophysical properties of ligand syn-1 (20 μM)
NMR were observed for complex 1b and 1c (see Supporting and complexes 1a–d (30 μM) were evaluated in dichloro-
Information File 1, Figures S11 and 12), with chemical shift methane (Supporting Information File 1, Figures S4–S8). The
variations in the range of 0.1 to 0.3 ppm for 1c. The little differ- UV–visible and fluorescence emission spectra (λexc = 345 nm)
Figure 4: Variable temperature 1H NMR of complex 1a in CDCl3 (7 mM) from −30 °C to 60 °C.
2468

Beilstein J. Org. Chem. 2019, 15, 2465–2472.
of ligand and complexes were similar and correspond to those catalyst loadings and under milder conditions (20 °C, full
of 9,10-diphenylanthracene [56,57]. The silver(I) coordination conversion after 12 h). As previously observed for inorganic Ag
on the ligand and the formation of supramolecular systems does salts [60], the catalyst efficiency for this cyclization slightly
not seem to affect the spectroscopic properties of the 9,10- depends on its anion nature (1a > 1c > 1b > 1d).
diphenylanthracene system.
To further demonstrate the catalytic properties of silver(I) com-
Silver catalysis
plexes 1a–d, we investigated their performance in the cycliza-
As silver(I) salts exhibit a high alkynophilicity [11-17], the new tion [63] of alkynone 3 [63-65] in the presence of benzylamine,
complexes 1a–d were evaluated as homogeneous catalysts in as a nucleophile (Table 2) that lead to substituted pyrrole 5.
two tandem addition/cycloisomerization reactions using alkynes This tandem condensation/cycloisomerization was previously
2 and 3.
reported in 78% yield using AgOTf at 5 mol % (reaction time
3.5 h, 50 °C) [63]. Noteworthy, at 50 °C the transformation
2-Alkynylbenzaldehyde 2 [58,59] was chosen as the first model occurs in 35% yield without any catalyst (Table 2, entry 1). In
substrate for a cyclization reaction in the presence of methanol our hands, using AgOTf (2.5 mol %), the product was obtained
as a second nucleophile. This tandem addition/cycloisomeriza- in 73% yield meanwhile 67–76% yield were reached when
tion was previously described in high yields (>95%) using silver complexes 1a–d at 1 mol % were employed (Table 2,
5 mol % catalyst loadings starting from 2-(alkynyl)quinoline-3- entries 2–6). Interestingly, a lower catalytic loading of
carbaldehyde [60,61] with AgOTf catalyst and starting from 0.5 mol % allowed the isolation of 73% of pyrrole 5 in the pres-
2-alkynylbenzaldehyde derivatives [62] in the presence of a ence of catalysts 1a and 1b (Table 2, entries 7 and 8). Under the
macrocyclic pyridine-tetraaza complex of Ag(I) as a catalyst. In same conditions, the catalytic efficiency of 1c and 1d was
our control experiment, alkyne 2 was converted into product 4 slightly lower (64–67 % yield) but similar to AgOTf at
in high yield (88 %) using AgOTf at 5 mol % (Table 1, entry 1). 2.5 mol % (Table 2, entries 9 and 10). For this second
Interestingly, 1-methoxyisochromene 4 can also be isolated in tandem model cyclization, the effect of the anion on the
89% yield, using a AgOTf catalytic loading of 1 mol % catalysts’ efficiency was weak. Finally, this second model addi-
(Table 1, entry 2). All silver complexes 1a–d (1 mol %) effi- tion/cycloisomerization was successfully catalyzed by silver
ciently catalyzed the intramolecular cyclization with 65–92% complexes 1a–b also at lower loadings (0.5 mol %) than
yields (Table 1, entries 3–7). To our delight, the transformation AgOTf.
also reached 92% yield by employing 1a at 0.5 mol % (Table 1,
entry 4). Compared to literature [60-62], catalyst 1a is effective
Table 2: Condensation/cycloisomerization of alkyne 3.a
for the tandem cyclization of 2-alkynylbenzaldehyde 2 at lower
Table 1: Addition/cycloisomerization of alkyne 2.a
Entry
[Ag] catalyst Loading (mol %)
Yieldb (%)
1
2
3
4
5
6
7
8
–
–
2.5
1
1
1
35
73
76
67
72
76
73
73
67
64
AgOTf
1a
1b
1c
1d
1a
1b
1c
Entry
[Ag] catalyst Loading (mol %)
Yieldb (%)
1
2
3
4
5
6
7
AgOTf
AgOTf
1a
1a
1b
5
1
1
0.5
1
88
89
92
92
73
85
65
1
0.5
0.5
0.5
0.5
9
10
1c
1d
1
1
1d
aUnless specified, all the reactions were performed at 50 °C under
argon atmosphere in dry 1,2-dichloroethane for 12–16 h, in the pres-
ence of alkyne 3 (27 mg, 0.2 mmol), benzylamine (0.3 mmol) and a
silver(I) catalyst (0.5–2.5 mol %). bIsolated yield.
aUnless specified, all the reactions were carried out in dry CH2Cl2 at
room temperature for 12–16 h with alkyne 2 (30 mg, 0.15 mmol),
MeOH (0.45 mmol) and a silver(I) catalyst (0.5–5 mol %). bIsolated
yield.
2469

Beilstein J. Org. Chem. 2019, 15, 2465–2472.
Conclusion
hydrous CH2Cl2 (1 mL) and benzylamine (33 µL, 0.3 mmol)
9,10-Diphenylanthracene with two ortho-substituted thioether were successively added. The mixture was stirred at 50 °C for
functional groups is an attractive scaffold which allowed us to 12 h. The solution was concentrated under reduced pressure and
design and prepare a stable syn-atropisomer ligand 1 which can the crude product was purified by column chromatography on
direct coordinate towards the same half-space. Three macro- silica gel (eluent: petrol ether/ethyl acetate 70:1) to obtain
cyclic silver complexes were then synthesized and their coordi- pyrrole 5.
nation modes revealed by X-ray diffraction were depended on
the nature of the anion, i.e., M2L2 for –OTf/–OTFA and M6L4
for NO3–. With prochiral thioether groups, M2L2 macrocycles
Supporting Information
were obtained as mixtures of diastereoisomers due to the two
Supporting Information File 1
possible arrangements of the coordinated ligands (head-to-head
or head-to-tail) resulting into different spatial arrangements. In
solution, the architectures of silver(I) complexes with ligand
syn-1 seemed to be similar to the solid-state structures. The
silver(I) complexes were evaluated as homogeneous catalysts in
two tandem addition/cycloisomerization reactions on model
alkynes to give the expected cyclization products in excellent
yields, also by using 0.5 mol % catalytic loading, with efficien-
cies similar to those reported in the literature [60-63] with inor-
ganic silver salts and complexes employed at higher loadings
(2.5–5 mol %). The use of original and effective silver com-
plexes might be a way to lower the catalytic loading in silver-
catalyzed transformations and opens perspectives to the design
of new asymmetric ligands.
Synthesis and characterization data of ligand and silver
complexes, details of X-ray structures.
[https://www.beilstein-journals.org/bjoc/content/
supplementary/1860-5397-15-239-S1.pdf]
Supporting Information File 2
Crystallographic structures CCDC 1883532, 1883535,
1883536, 1883538 and 1883674 of ligand 1 and silver
complexes 1a–d (.cif files).
[https://www.beilstein-journals.org/bjoc/content/
supplementary/1860-5397-15-239-S2.zip]
Acknowledgements
Financial support was provided by the China Scholarship
Council (Z.C. Ph.D. fellowship), the University of Bordeaux
Experimental
General procedure for the synthesis of silver(I) complexes and Centre National de la Recherche Scientifique. The authors
1a–d: To a solution of ligand 1 (15 mg, 0.0355 mmol) in an- acknowledge Damien Jardel and Clotilde Davies for their
hydrous CH2Cl2 (1 mL) was added the corresponding silver salt contribution to the synthesis of the syn-ligand, Stéphane Massip
(0.0355 mmol, 1.0 equiv) under argon atmosphere at room tem- for the resolution of the corresponding crystallographic struc-
perature. The mixture was stirred for 4 h. The clear solution was ture.
concentrated to ca. 0.3 mL and diethyl ether (2.0 mL) was
ORCID® iDs
slowly added to afford a precipitation. After filtration, the iso-
lated solid was washed with diethyl ether and dried under
vacuum.
Cybille Rossy - https://orcid.org/0000-0003-4107-9977
Brigitte Bibal - https://orcid.org/0000-0003-0146-8396
References
General procedure for the acetalization/cycloisomerization
of alkyne 2: An oven-dried Schlenk tube was charged with the
silver(I) catalyst (0.5–5 mol %), then degassed and backfilled
with argon for three times. A solution of alkyne 2 (30 mg,
1. Castellino, S.; Sims, J. J. Tetrahedron Lett. 1984, 25, 4059–4062.
doi:10.1016/s0040-4039(01)90181-9
2. Lathbury, D.; Gallagher, T. Tetrahedron Lett. 1985, 26, 6249–6252.
doi:10.1016/s0040-4039(00)95065-2
3. Grimaldi, J.; Cormons, A. Tetrahedron Lett. 1986, 27, 5089–5090.
0.15 mmol) in anhydrous CH2Cl2 (1 mL) and dry MeOH
(18 µL, 0.45 mmol) were successively added. The mixture was
stirred at room temperature for 12 h. The solution was concen-
trated and the crude residue was purified by column chromatog-
raphy on silica gel (eluent: petrol ether/ethyl acetate 50:1) to
obtain 1-methoxyisochromene 4.
doi:10.1016/s0040-4039(00)85140-0
4. Pale, P.; Chuche, J. Tetrahedron Lett. 1987, 28, 6447–6448.
doi:10.1016/s0040-4039(00)96884-9
5. Sawamura, M.; Hamashima, H.; Ito, Y. J. Org. Chem. 1990, 55,
5935–5936. doi:10.1021/jo00311a007
6. Hayashi, T.; Uozumi, Y.; Yamazaki, A.; Sawamura, M.;
Hamashima, H.; Ito, Y. Tetrahedron Lett. 1991, 32, 2799–2802.
doi:10.1016/0040-4039(91)85090-r
General procedure for condensation/cycloisomerization of
alkyne 3: A dry Schlenk tube charged with silver catalyst
(0.5–2.5 mol %) was degassed and backfilled with argon for
three times. A solution of alkyne 3 (27 mg, 0.2 mmol) in an-
7. Kimura, M.; Fugami, K.; Tanaka, S.; Tamaru, Y. Tetrahedron Lett.
1991, 32, 6359–6362. doi:10.1016/0040-4039(91)80169-7
2470

Beilstein J. Org. Chem. 2019, 15, 2465–2472.
8. Marshall, J. A.; Wang, X. J. J. Org. Chem. 1991, 56, 960–969.
doi:10.1021/jo00003a013
35.Küppers, H.-J.; Wieghardt, K.; Tsay, Y.-H.; Krüger, C.; Nuber, B.;
Weiss, J. Angew. Chem., Int. Ed. Engl. 1987, 26, 575–576.
doi:10.1002/anie.198705751
36.De Groot, B.; Jenkins, H. A.; Loeb, S. J. Inorg. Chem. 1992, 31,
203–208. doi:10.1021/ic00028a015
37.Blake, A. J.; Gould, R. O.; Parsons, S.; Radek, C.; Schröder, M.
Angew. Chem., Int. Ed. Engl. 1995, 34, 2374–2376.
doi:10.1002/anie.199523741
9. Cooper, D. M.; Grigg, R.; Hargreaves, S.; Kennewell, P.; Redpath, J.
Tetrahedron 1995, 51, 7791–7808. doi:10.1016/0040-4020(95)00397-q
10.Yanagisawa, A.; Nakashima, H.; Ishiba, A.; Yamamoto, H.
J. Am. Chem. Soc. 1996, 118, 4723–4724. doi:10.1021/ja9603315
11.Halbes-Letinois, U.; Weibel, J.-M.; Pale, P. Chem. Soc. Rev. 2007, 36,
759–769. doi:10.1039/b602151b
12.Alvarez-Corral, M.; Mun
̃
38.Alberto, R.; Nef, W.; Smith, A.; Kaden, T. A.; Neuburger, M.;
Zehnder, M.; Frey, A.; Abram, U.; Schubiger, P. A. Inorg. Chem. 1996,
35, 3420–3427. doi:10.1021/ic951421y
39.Blake, A. J.; Li, W.-S.; Lippolis, V.; Schröder, M. Chem. Commun.
1997, 1943–1944.
40.Alberto, R.; Angst, D.; Schubiger, A. P.; Abram, U.; Ortner, K.;
Kaden, T. A. Chem. Commun. 1999, 1513–1514.
doi:10.1039/a903455b
Chem. Rev. 2008, 108, 3174–3198. doi:10.1021/cr078361l
13.Belmont, P.; Parker, E. Eur. J. Org. Chem. 2009, 6075–6089.
doi:10.1002/ejoc.200900790
14.Muñoz, M. P. Chem. Soc. Rev. 2014, 43, 3164–3184.
doi:10.1039/c3cs60408j
15.Fang, G.; Bi, X. Chem. Soc. Rev. 2015, 44, 8124–8173.
doi:10.1039/c5cs00027k
16.Blanc, A.; Bénéteau, V.; Weibel, J.-M.; Pale, P. Org. Biomol. Chem.
2016, 14, 9184–9205. doi:10.1039/c6ob01468b
17.Sekine, K.; Yamada, T. Chem. Soc. Rev. 2016, 45, 4524–4532.
doi:10.1039/c5cs00895f
18.Zheng, Q.-Z.; Jiao, N. Chem. Soc. Rev. 2016, 45, 4590–4627.
doi:10.1039/c6cs00107f
19.Alderson, J. M.; Corbin, J. R.; Schomaker, J. M. Acc. Chem. Res.
2017, 50, 2147–2158. doi:10.1021/acs.accounts.7b00178
20.Fang, G.; Cong, X.; Zanoni, G.; Liu, Q.; Bi, X. Adv. Synth. Catal. 2017,
359, 1422–1502. doi:10.1002/adsc.201601179
41.Blake, A. J.; Champness, N. R.; Howdle, S. M.; Webb, P. B.
Inorg. Chem. 2000, 39, 1035–1038. doi:10.1021/ic991145d
42.Casula, A.; Nairi, V.; Fernández-Moreira, V.; Laguna, A.; Lippolis, V.;
Garau, A.; Gimeno, M. C. Dalton Trans. 2015, 44, 18506–18517.
doi:10.1039/c5dt02723c
43.Chang, Y.-P.; Levason, W.; Reid, G. Dalton Trans. 2016, 45,
18393–18416. doi:10.1039/c6dt03409h
44.Mongin, C.; Pianet, I.; Jonusauskas, G.; Bassani, D. M.; Bibal, B.
ACS Catal. 2015, 5, 380–387. doi:10.1021/cs5016063
45.Cao, Z.; Bassani, D. M.; Bibal, B. Chem. – Eur. J. 2018, 24,
18779–18787. doi:10.1002/chem.201804322
21.Naodovic, M.; Yamamoto, H. Chem. Rev. 2008, 108, 3132–3148.
doi:10.1021/cr068413r
46.Nikitin, K.; Müller-Bunz, H.; Ortin, Y.; Muldoon, J.; McGlinchey, M. J.
22.Pellissier, H. Chem. Rev. 2016, 116, 14868–14917.
doi:10.1021/acs.chemrev.6b00639
Org. Lett. 2011, 13, 256–259. doi:10.1021/ol102665y
47.Marriott, P. J.; Lai, Y.-H. J. Chromatogr. A 1998, 447, 29–41.
doi:10.1016/0021-9673(88)90004-0
48.Zehm, D.; Fudickar, W.; Linker, T. Angew. Chem., Int. Ed. 2007, 46,
7689–7692. doi:10.1002/anie.200700443
49.Zehm, D.; Fudickar, W.; Hans, M.; Schilde, U.; Kelling, A.; Linker, T.
Chem. – Eur. J. 2008, 14, 11429–11441. doi:10.1002/chem.200801355
50.Suzuki, A.; Kondo, K.; Akita, M.; Yoshizawa, M. Angew. Chem., Int. Ed.
2013, 52, 8120–8123. doi:10.1002/anie.201302789
51.Yazaki, K.; Akita, M.; Prusty, S.; Chand, D. K.; Kikushi, T.; Sato, H.;
Yoshizawa, M. Nat. Commun. 2017, 8, 15914–15921.
doi:10.1038/ncomms15914
52.Iida, A.; Yamaguchi, S. Chem. Commun. 2009, 3002–3004.
doi:10.1039/b901794a
53.Moon, H.; Jun, Y. W.; Kim, D.; Ryu, H. G.; Wang, T.; Kim, K. H.;
Huh, Y.; Jung, J.; Ahn, K. H. Chem. – Asian J. 2016, 11, 2518–2523.
doi:10.1002/asia.201600986
23.Türkmen, Y. E.; Montavon, T. J.; Kozmin, S. A.; Rawal, V. H.
J. Am. Chem. Soc. 2012, 134, 9062–9065. doi:10.1021/ja302537j
24.Zeng, Y.; Zhang, L.; Zhao, Y.; Ni, C.; Zhao, J.; Hu, J.
J. Am. Chem. Soc. 2013, 135, 2955–2958. doi:10.1021/ja312711c
25.Zeng, Y.; Hu, J. Chem. – Eur. J. 2014, 20, 6866–6870.
doi:10.1002/chem.201402846
26.Tseberlidis, G.; Dell'Acqua, M.; Valcarenghi, D.; Gallo, E.; Rossi, E.;
Abbiati, G.; Caselli, A. RSC Adv. 2016, 6, 97404–97419.
doi:10.1039/c6ra22231e
27.Ji, J.-X.; Au-Yeung, T. T.-L.; Wu, J.; Yip, C. W.; Chan, A. S. C.
Adv. Synth. Catal. 2004, 346, 42–44. doi:10.1002/adsc.200303148
28.Yao, X.; Li, C.-J. Org. Lett. 2005, 7, 4395–4398.
doi:10.1021/ol051575+
29.Takechi, S.; Yasuda, S.; Kumagai, N.; Shibasaki, M.
Angew. Chem., Int. Ed. 2012, 51, 4218–4222.
doi:10.1002/anie.201200520
30.Su, Y.; Lu, M.; Dong, B.; Chen, H.; Shi, X. Adv. Synth. Catal. 2014,
356, 692–696. doi:10.1002/adsc.201300785
54.Belyaev, A.; Chen, Y.-T.; Su, S.-H.; Tseng, Y.-J.; Karttunen, A. J.;
Tunik, S. P.; Chou, P.-T.; Koshevoy, I. O. Chem. Commun. 2017, 53,
10954–10957. doi:10.1039/c7cc06882d
31.Chen, Q.-A.; Zeng, W.; Wang, D.-W.; Zhou, Y.-G. Synlett 2009,
2236–2241. doi:10.1055/s-0029-1217805
32.Iglesias-Sigüenza, J.; Ros, A.; Díez, E.; Magriz, A.; Vázquez, A.;
Álvarez, E.; Fernández, R.; Lassaletta, J. M. Dalton Trans. 2009,
8485–8488. doi:10.1039/b910846g
55.Du, C.; Ye, S.; Liu, Y.; Guo, Y.; Wu, T.; Liu, H.; Zheng, J.; Cheng, C.;
Zhu, M.; Yu, G. Chem. Commun. 2010, 46, 8573–8575.
doi:10.1039/c0cc04147e
56.Meech, S. R.; Phillips, D. J. Photochem. 1983, 23, 193–217.
doi:10.1016/0047-2670(83)80061-6
33.Prakash, O.; Joshi, H.; Kumar, U.; Sharma, A. K.; Singh, A. K.
Dalton Trans. 2015, 44, 1962–1968. doi:10.1039/c4dt02813a
34.Rasheed, O. K.; Bawn, C.; Davies, D.; Raftery, J.; Vitorica-Yrzebal, I.;
Pritchard, R.; Zhou, H.; Quayle, P. Eur. J. Org. Chem. 2017,
5252–5261. doi:10.1002/ejoc.201701033
57.Suzuki, K.; Kobayashi, A.; Kaneko, S.; Takehira, K.; Yoshihara, T.;
Ishida, H.; Shiina, Y.; Oishi, S.; Tobita, S. Phys. Chem. Chem. Phys.
2009, 11, 9850–9860. doi:10.1039/b912178a
58.Sakamoto, T.; Kondo, Y.; Miura, N.; Hayashi, K.; Yamanaka, H.
Heterocycles 1986, 24, 2311–2314. doi:10.3987/r-1986-08-2311
2471

Beilstein J. Org. Chem. 2019, 15, 2465–2472.
59.Dyker, G.; Stirner, W.; Henkel, G. Eur. J. Org. Chem. 2000,
1433–1441.
doi:10.1002/(sici)1099-0690(200004)2000:8<1433::aid-ejoc1433>3.0.c
o;2-7
60.Godet, T.; Vaxelaire, C.; Michel, C.; Milet, A.; Belmont, P.
Chem. – Eur. J. 2007, 13, 5632–5641. doi:10.1002/chem.200700202
61.Parker, E.; Leconte, N.; Godet, T.; Belmont, P. Chem. Commun. 2011,
47, 343–345. doi:10.1039/c0cc02623a
62.Dell’Acqua, M.; Castano, B.; Cecchini, C.; Pedrazzini, T.; Pirovano, V.;
Rossi, E.; Caselli, A.; Abbiati, G. J. Org. Chem. 2014, 79, 3494–3505.
doi:10.1021/jo5002559
63.Harrison, T. J.; Kozak, J. A.; Corbella-Pané, M.; Dake, G. R.
J. Org. Chem. 2006, 71, 4525–4529. doi:10.1021/jo060382c
64.Trost, B. M.; Rudd, M. T. J. Am. Chem. Soc. 2005, 127, 4763–4776.
doi:10.1021/ja043097o
65.Jazkewitsch, O.; Mondrzyk, A.; Staffel, R.; Ritter, H. Macromolecules
2011, 44, 1365–1371. doi:10.1021/ma1027627
License and Terms
This is an Open Access article under the terms of the
Creative Commons Attribution License
(http://creativecommons.org/licenses/by/4.0). Please note
that the reuse, redistribution and reproduction in particular
requires that the authors and source are credited.
The license is subject to the Beilstein Journal of Organic
Chemistry terms and conditions:
(https://www.beilstein-journals.org/bjoc)
The definitive version of this article is the electronic one
which can be found at:
doi:10.3762/bjoc.15.239
2472