Design, Synthesis, and Implementation of Sodium Silylsilanolates as Silyl Transfer Reagents

Article abstract of DOI:10.1021/acscatal.1c02733

There is an increasing demand for facile delivery of silyl groups onto organic bioactive molecules. One of the common methods of silylation via a transition-metal-catalyzed coupling reaction employs hydrosilane, disilane, and silylborane as major silicon sources. However, the labile nature of the reagents or harsh reaction conditions sometimes render them inadequate for the purpose. Thus, a more versatile alternative source of silyl groups has been desired. We hereby report a design, synthesis, and implementation of storable sodium silylsilanolates that can be used for the silylation of aryl halides and pseudohalides in the presence of a palladium catalyst. The developed method allows a late-stage functionalization of polyfunctionalized compounds with a variety of silyl groups. Mechanistic studies indicate that (1) a nucleophilic silanolate attacks a palladium center to afford a silylsilanolate-coordinated arylpalladium intermediate and (2) a polymeric cluster of silanolate species assists in the intramolecular migration of silyl groups, which would promote an efficient transmetalation.

Full text of DOI:10.1021/acscatal.1c02733

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Research Article
Design, Synthesis, and Implementation of Sodium Silylsilanolates as
Silyl Transfer Reagents
Hiroki Yamagishi, Hayate Saito, Jun Shimokawa,* and Hideki Yorimitsu*
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ABSTRACT: There is an increasing demand for facile delivery of
silyl groups onto organic bioactive molecules. One of the common
methods of silylation via a transition-metal-catalyzed coupling
reaction employs hydrosilane, disilane, and silylborane as major
silicon sources. However, the labile nature of the reagents or harsh
reaction conditions sometimes render them inadequate for the
purpose. Thus, a more versatile alternative source of silyl groups
has been desired. We hereby report a design, synthesis, and
implementation of storable sodium silylsilanolates that can be used for the silylation of aryl halides and pseudohalides in the presence
of a palladium catalyst. The developed method allows a late-stage functionalization of polyfunctionalized compounds with a variety
of silyl groups. Mechanistic studies indicate that (1) a nucleophilic silanolate attacks a palladium center to afford a silylsilanolate-
coordinated arylpalladium intermediate and (2) a polymeric cluster of silanolate species assists in the intramolecular migration of
silyl groups, which would promote an efficient transmetalation.
KEYWORDS: silylsilanolate, silanolate salts, silylation, palladium, DFT calculation
INTRODUCTION
■
Silicon typically adopts four covalent, tetrahedrally disposed
bonds in molecular architectures, so that it resembles one of
the most fundamental elements of life, carbon. The major
difference between these two group 14 elements lies in
electronegativity and the bond length to the adjacent atoms.
Thus, in the realm of silicon-containing drugs and bioactive
molecules,1 a carbon atom could be exchanged to a silicon
atom as a bioisostere to modify the physical and biological
characteristics. Through these strategies known as “silicon
switch”,1a silicon-containing bioactive molecules have been
successfully devised (Figure 1). Retinoid X receptor (RXR)-
selective retinoid antagonist, bexarotene, has been redesigned
to disila-bexarotene by exchanging two carbon atoms with
silicon atoms without any detrimental effect on bioactivity.2
Figure 1. Sila-analogs developed via a carbon/silicon switch strategy.
The silicon switch strategy has also effectively proposed potent
sila-analogs of acaricide cyflumetofen3 and p38 MAP kinase
of an appropriate reagent that is amenable even to the late-
inhibitor doramapimod4 (BIRB 796). As illustrated in these
stage functionalization of complex molecules through tran-
examples, the substitution of a tert-butyl group with a
bioisosteric trimethylsilyl group is an intriguing tactic for
changing physicochemical properties such as human micro-
somal stability without lowering the biological activities.
sition-metal-catalyzed silylation of aryl halides or C−H
silylation6 of arenes (Figure 2A). Commonly used reagents
for those silylation can be mainly classified into three silicon
Despite this successful implementation of the silicon switch
strategy, synthetic approaches to complex silicon-containing
molecules have been restricted. Selective deprotonation and
Received: June 18, 2021
Revised: July 10, 2021
subsequent trapping with silicon electrophiles, such as
trimethylsilyl cyanide,5 constitute a viable strategy only if the
substrate allows strongly basic conditions. Thus, we hypothe-
sized that the synthetic difficulty would be due to the scarcity
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a b c
, ,
Scheme 1. Synthesis of Sodium Silylsilanolates
a
1.05 equiv of 1,2-dichlorotetramethyldisilane, 1.0 equiv of BnMgCl,
b
tetrahydrofuran (THF), 0−50 °C, 4 h. 1.03 equiv of 1,2-
dichlorotetramethyldisilane, 1.0 equiv of tBuLi, hexane, reflux, 13 h.
c
1.0 equiv of 1,2-dichlorotetramethyldisilane, 1.0 equiv of allylZnCl,
THF, 0 °C to r.t., 4 h.
silanolate as a catapult. We hypothesized the mode of
migration of a silyl group from silylsilanolate, as shown in
Figure 2C, based on a similar system for arylsilanolate
proposed by Denmark.14g In contrast to the ordinary disilanes,
an anionic silylsilanolate can act as a nucleophile that attacks
the palladium(II) center to form a silylsilanolate-coordinated
intermediate. This proximity effect would facilitate an
intramolecular delivery of the terminal silyl group to the
palladium center, with concomitant formation of a waste
polysiloxane.
Figure 2. Blueprint for development of sodium silylsilanolate.
species: hydrosilanes, disilanes, and silylboranes. Hydrosilanes
often provide reduced products during a transition-metal-
catalyzed silylation reaction, which often complicates the
reaction consequences.7 Particularly, trimethylhydrosilane is a
gaseous and pyrophoric reagent that is impractical to use in the
laboratory. Disilanes are less likely to cause transmetalation so
that relatively high temperatures (>100 °C) and strong bases
are often necessary for the activation.8 In most cases,
hexamethyldisilane is employed as a reagent, and a judicious
choice of ligands is often necessary for each substrate. Thus,
the use of disilanes leads to the reduced variation of the silyl
group and functional group tolerance. Silylboranes9 are
silylation reagents that are now frequently used in transition-
metal-catalyzed silylation of aryl (pseudo)halides.9b,10 While
silylboranes bearing bulky silyl groups are reported to be
stable,11 typical silylborane Me2PhSi−Bpin is known to be air-
and moisture-sensitive.9b Me3Si−Bpin has long been consid-
ered fairly labile, so that it is hydrolyzed during purification.12
As the synthetic preparation of Me3Si−Bpin was reported to be
possible only quite recently,13 the utility of silylboranes as the
source of trimethylsilyl groups is currently yet to be revealed.
In terms of nucleophilic silylation reactions, the simplest
trialkylsilyl group, trimethylsilyl, is definitely not a trivial one.
By probing these three reagents, it is now evident that the
development of a novel practical nucleophilic silylating reagent
is necessary for more efficient silylation under mild conditions.
Herein, we propose sodium trimethylsilyldimethylsilanolate
(Na+1−) as a new silylating reagent that works in the presence
of palladium catalyst (Figure 2B). The design of this reagent
was inspired by analogy to arylsilanolates that have been
known as reagents for transferring aryl groups in palladium-
catalyzed cross-coupling reactions.14 The molecular structure
of Na+1− contains one Si−Si bond that connects a
trimethylsilyl group to be delivered and a nucleophilic
RESULTS AND DISCUSSION
■
Na+1− was easily synthesized from commercially available
chloropentamethyldisilane 1 over two steps (Scheme 1A):
hydrolysis of a chlorosilane in an acetate buffer to afford a
silanol and the subsequent deprotonation with NaH. The
reagent was obtained as an analytically pure, mildly
hygroscopic, and thermally stable white powder that can be
easily handled in a dry atmosphere. Sodium silylsilanolates
other than Na+1− were synthesized, as shown in Scheme 1B.
Commercially available 1,2-dichlorotetramethyldisilane was
treated with nucleophilic organometallic species (BnMgBr,
tBuLi, allylZnCl) to mediate monosubstitutions to give the
corresponding chlorodisilanes 2, 3, and 4.15 Hydrolysis of 2−4
followed by deprotonation with NaH provided the correspond-
ing sodium silylsilanolates Na+2−−Na+4− in good yields.
Na+2− and Na+3− were obtained as white solids, and Na+4−
was isolated as a sticky oil.
To evaluate the synthetic utility of sodium silylsilanolate, we
studied the silylation of aryl bromide 5 in the presence of a
palladium catalyst with Na+1− (Table 1). Under our optimized
standard conditions, treatment of ethyl 4-bromobenzoate (5)
with preformed MePhos Pd G4 (3 mol %)16 and Na+1− (2.0
equiv) in 1,2-dichloroethane (DCE) as the solvent at 50 °C for
2 h provided the silylated product 6 in 89% NMR yield (88%
isolated yield) (entry 1). The yield of 6 was competitive (83%)
with the use of the catalyst generated in situ from Pd2dba3 and
MePhos (entry 2). The influence of ligands on the efficiency of
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esters.17 The substrate with a formyl or acetyl group could be
transformed in good yield into 8 or 9. In the case of 9, the
reaction was performed at 25 °C to suppress the formation of
an α-arylated byproduct. Cyano and nitro groups could poison
a palladium catalyst. While a substrate with a cyano group was
converted into arylsilane 10 in good yield, arylsilane 11 with a
nitro group was obtained only in moderate yield. Fluoro and
vinyl substituents were also confirmed to be compatible (12,
13). Substrates with electron-rich substituents, such as
methoxy (p-, m-, and o-OMe)-, silyloxy-, amino-, and amido-
substituted aryls, were generally transformed into arylsilanes
(14−19). A wide range of heteroaryl trimethylsilanes could
also be synthesized under our silylation reaction (Table 2B).
Electron-rich heteroarenes, such as benzofuran 20, benzothio-
phene 21, N-(p-toluenesulfonyl)indole 22, and N-methylpyr-
rolopyridine 23, were obtained in excellent yields. A sterically
hindered pyrazole was converted to the silylated product 24,
albeit in moderate yield (53%). Electron-deficient heteroarenes
were also compatible. The conditions were amenable to the
syntheses of quinoline 25, as well as pyridine 26 and
pyrimidines 27 and 28. As an entry to alkenes, β-bromostyrene
could be transformed into the trimethylsilylated derivative 29
(Table 2C). The reaction was also applicable to the synthesis
of known biologically relevant compounds (Table 2D).
Acetylcholinesterase inhibitor zifrosilone18 (30) was synthe-
sized from the commercially available 3′-bromo-2,2,2-trifluor-
omethylacetophenone in good yield. A potent inhibitor of the
drug-resistant S31N mutant of the M2 ion channel of influenza
A virus 3119 was synthesized from the corresponding aryl
bromide even in the presence of a free hydroxy and a
secondary amino group.
a b
,
Table 1. Optimization of the Reaction Conditions
In an attempt to demonstrate the applicability of our
method to the late-stage silylation, we tested several drugs and
drug-like molecules containing aryl bromides (Table 2E).
Trimethylsilylated analogs of sulfadimethoxine 32 and ataluren
33 were synthesized in 77% and 53% respective yields from the
corresponding aryl bromides. The bromide moiety of SC-558
was similarly converted to a trimethylsilyl group to give a
celecoxib analog 34 in 76% yield. Nicergoline was also
trimethylsilylated to give an ergot alkaloid analog 35 in 64%
yield. An increased amount of the catalyst and silylsilanolate
was required for ataluren and celecoxib analogs, whose
oxadiazole and sulfonamide moieties might work inhibitively
to the catalyst. Thus, in the case of the ataluren analog, the
slower rate of the coupling reaction seemed to result in partial
hydrolysis of the ester moiety in 33. The sila-analog of
fenazaquin 36,20 in which a tert-butyl group is replaced with a
trimethylsilyl group, was analogously synthesized from the
corresponding aryl bromide in excellent yield. Just to compare
the functional group tolerance, the known palladium-catalyzed
silylation conditions8h using hexamethyldisilane were applied
for the syntheses of relatively functionalized 28 and 32, which
resulted in 31 and 34% respective yields. The reaction
proceeded in concomitant with the formation of the reduced
products both in ca. 30% yields with about 30% recovery of the
starting material (see the Supporting Information (SI)). These
results indicate that the new silylation strategy using sodium
silylsilanolate is suitable for the highly versatile syntheses of
sila-analogs of bioactive molecules.
a
1
Yields were determined by H NMR using 1,3,5-trimethoxybenzene
b
as an internal standard. Isolated yield (0.50 mmol scale).
the reaction was examined first. Monodentate ligands, PCy3,
CyJohnPhos, and JohnPhos afforded 6 in competitive yet
lower yields (51−81%) (entries 3−5).
An acceptable result was also obtained with N-heterocyclic
carbene complex (IPr)Pd(allyl)Cl as a catalyst (73%) (entry
6). A bidentate phosphine ligand, dppe, was ineffective (7%) in
the current reaction system (entry 7). Use of lithium
silylsilanolate Li+1− or potassium silylsilanolate K+1− showed
lower efficiency (entries 8 and 9), which underscored the
importance of the choice of the countercation for efficient
silylation. The reaction in toluene was similarly efficient (74%),
while low yields were observed in THF and CH3CN with the
recovery of most of the substrates (entries 10−12) in
concomitant with the formation of the reduced product
(<20%). No conversion of 5 was observed in the absence of a
palladium catalyst (entry 13).
Next, we explored the reaction scope with respect to aryl
bromides (Table 2A). Silylation of 5 could be run even on a
5.0 mmol scale to afford 6 in excellent yield (92%). The
reaction could tolerate various electronic and steric properties
of substituents (6−11). Esters in 6 and 7 survived the
silylation conditions. This outcome is intriguing given that
trimethylsilanolates are generally used for the hydrolysis of
We applied the optimized silylation conditions to other aryl
halides and pseudohalides (Table 3). For electron-deficient
arenes, iodide, triflate, and chloride were silylated to provide 6
in high yields. Iodide could be transformed even at 25 °C. For
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a b c d
, , ,
Table 2. Scope of Silylation of Aryl Bromides
a
b
c
5.0 mmol scale. Temperature: 25 °C. NMR yield. Reaction conditions: 1.2 equiv of hexamethyldisilane, 1.5 mol % Pd2dba3, 9 mol % JohnPhos,
d
5.0 equiv of KF, 2.0 equiv of H2O, DMPU (0.90 mL), 100 °C, 12 h. 6 mol % MePhos Pd G4 and 3.0 equiv of Na+1− were used.
an electron-rich series, aryl iodide was also converted to the
corresponding product 14 in high yield, while triflate and
chloride showed low or no conversion even under the
optimized conditions. In the case of aryl fluoride, both
electron-withdrawing and electron-donating substrates re-
mained intact throughout the reaction conditions.9b,21
Silylation of aryl triflate and chloride on more functionalized
molecules was also achieved. The silylated products 37 and 38
were obtained from the estrone derivative (X = OTf) or
fenofibrate (X = Cl), respectively, in high yields. In the case of
a protected L-tyrosine derivative (X = OTf), the silylated
product 39 was obtained in good yield, albeit in an almost
racemized form. In terms of transition-metal-catalyzed
silylation, the reaction developed in this study is exceptional
in that most of the electron-rich/deficient aryl halides and
pseudohalides could be silylated under identical catalytic
reaction conditions.
With Na+2−−Na+4−, introduction of other silyl groups was
also possible in the current strategy (Table 4). Delivery of a
benzyldimethylsilyl group has been known to be inefficient
with a disilane8m or silylborane22 as a precursor. Under the
optimized conditions with Na+2−, a benzyldimethylsilyl group
could be introduced to afford both electron-deficient and
-donating arenes 40 and 41 in high yields. In the case of p-
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Table 3. Scope of Silylation of Aryl Halides and
a b c
, ,
Pseudohalides
a
b
c
Temperature: 25 °C. 6 mol % MePhos Pd G4 was used. NMR
yield.
a
Table 4. Scope of Silyl Groups
Figure 3. Sequential 31P NMR spectra on the ligand exchange of 44
with sodium silylsilanolate: (A) 44 in DCE at r.t., (B) 45 generated in
situ by the reaction of 44 with NaBAr4F at 0 °C, (C) 45 with 0.5 equiv
of Na+1− at −30 °C, and (D) 45 with total 1.0 equiv of Na+1− at −30
°C in DCE.
(44) was synthesized from 4-FC6H4Br, Pd(cod)(CH2SiMe3)2,
and SPhos.23 As reported by Hii, Pd complexes with SPhos
such as 44 were known to show two signals corresponding to
the monomer of 44 and its μ2-halo-bridged dimer (Figure
3A).24 Cationic Pd(II) species 45 was prepared in situ by the
reaction of 44 with NaBAr4 at 0 °C (ArF = 3,5-
F
(CF3)2C6H3),25 which showed a downfield shift of the 31P
NMR signal26 at 49.4 ppm (Figure 3B). Upon treatment of 45
with 0.5 equiv of Na+1− at −30 °C, a new 31P NMR signal
appeared (37.8 ppm), in addition to the broadened signal for
the remaining 45 (Figure 3C). After the addition of an
additional 0.5 equiv of Na+1− to the solution at −30 °C, 45
was fully consumed, leaving the species that shows the sharp
signal at 38.0 ppm with a broadened signal at 41.2 ppm (Figure
3D). The stoichiometry obtained in these experiments revealed
that the attack of Na+1− on 45 rapidly occurred and resulted in
the formation of a Pd species 46 bearing a silylsilanolate
substituent.14g We attributed the slight shift of the broadened
signal of 45 in Figure 3C to the fast equilibrium between the
free cationic 45 and a complex of 45 and 46. By analogy to
Figure 3A, the sharp signal at 38.0 ppm and the broad peak at
41.2 ppm in Figure 3D could be respectively assigned as the
monomeric species of 46 and its silanolate-bridged dimer. A
19F NMR study was separately conducted for the same time
courses (see the SI). The product that formed in the reaction
was confirmed to be the coupled product 4-fluorotrimethylsi-
a
Reported yield in Ref 18.
bromoanisole, the yield of 41 under the current conditions
(94%) is higher than the one in the known result with
silylborane-based conditions.22 While no coupling reaction
with tert-butyldimethylsilyl and allyldimethylsilyl groups has so
far been reported under transition-metal-catalyzed conditions
with conventional silylating reagents, our silylation method
with silylsilanolates Na+3− and Na+4− enabled an easy access
to the tert-butyldimethylsilyl arene 42 (62%) and allylsilylated
arene 43 (70%). These results indicate that the core structure
of silylsilanolate would be generally more viable for the
transmetalation of various silyl groups than the known
silylating reagents.
To gain mechanistic insights into the silylation with
silylsilanolates, we conducted 31P and 19F NMR experiments
(Figure 3 and S1). T-shape complex SPhosPdBr(4-FC6H4)
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Figure 4. Energy profile for migration of the silyl group of silylsilanolate to the palladium atom at the ωB97X-D/def2-TZVP/SMD (DCE)//
ωB97X-D/def2-SVP level of theory at 323.15 K.
lylbenzene from the 19F NMR spectrum. Also, after the
solution of 46 was warmed to room temperature, the 19F NMR
signal showed the disappearance of 46. These NMR
experiments corroborated the hypothesis that silylsilanolate-
coordinated species 46 was a viable intermediate for the
palladium-catalyzed silylation.
Figure 4 (silanolate dimer-assisted pathway). The complex-
ation of INT-1 with the sodium trimethylsilanolate dimer 49
proceeds exergonically to afford INT-B1. The intramolecular
transfer of the trimethylsilyl group to the palladium atom
requires a lower activation barrier (ΔG‡ = 28.1 kcal/mol) via
TS-B to afford INT-B2 than that via TS-A. In the calculated
structure of TS-B shown in Figure 4, the silicate moiety on the
Si2 atom forms a trigonal bipyramidal structure, where Si1 and
O1 atoms occupy the apical positions. NBO analysis revealed
that the NPA charge of the trimethylsilyl unit of the
silylsilanolate in TS-B (−0.552e) was significantly more
negative than the one in TS-A1 (−0.110e) (see the SI).
Also, each of NPA charges of Si1 and Si2 atoms in TS-B is +
0.875e and + 2.081e, which indicates that the Si1 atom is more
negatively charged. Thus, through the formation of a silicate-
like structure in TS-B, the trimethylsilyl unit containing the Si1
atom is rendered anionic to result in the smooth combination
of the Si1 unit with the nearby palladium atom. Dissociation of
a silanolate-bearing disiloxane moiety 50 from INT-B2 affords
INT-B3. Cluster 50 that goes off in the course of the reaction
would again assist in the activation of the transfer of the silyl
group. Of note, our simplified calculation model based on a
sodium silanolate dimer does not exclude the possibility of the
interference of a larger cluster of silanolates. From these
results, we conclude that the transfer of the silyl group
proceeds with the aid of a cluster of silanolates that would exist
in the reaction mixture.27 A calculation on the reductive
elimination of 48 indicates that the final reductive elimination
is a low-barrier process through TS-RE (ΔG‡ = 5.7 kcal/mol)
to exergonically afford INT-B4. This result is consistent with
To figure out the mechanism of the migration of the silyl
groups to the palladium atom of 46, DFT calculations were
carried out (Figure 4). Based on the results of the 31P NMR
experiments, silylsilanolate-coordinated arylpalladium INT-1
was chosen as a reliable starting point of the calculated
pathway. To simplify the calculations, the ligand was modeled
as 2-(diisopropylphosphino)biphenyl. A pathway for the
migration of the silyl group directly from INT-1 (non-assisted
pathway) was initially examined. The energy profile is
summarized on the left side of Figure 4. The pathway for
the direct elimination of dimethylsilanone (47) from INT-1 to
afford INT-A2 via TS-A and INT-A1 was found to be
endergonic probably because of the thermodynamically
unfavorable generation of a silanone. As the calculated
activation energy from INT-1 to TS-A is 34.8 kcal/mol, direct
transfer of the silyl group to give 48 is not a likely pathway. We
next hypothesized that sodium silylsilanolates that exist in large
excess compared with the palladium species would promote
the migration of a silyl group. Experimental observations
revealed that non-polar solvents such as DCE and toluene were
effective for the silylation, so we assumed that an aggregated
cluster of sodium silylsilanolates may have an effect on the
migration process. To simplify the calculation, an activator was
modeled as sodium trimethylsilanolate dimer 49. The energy
profile with the aid of 49 is summarized on the right side of
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the fact that such a silylpalladium species was not observed
either in the 31P or 19F NMR experiments.
ACKNOWLEDGMENTS
■
This work was supported by JSPS KAKENHI Grant Numbers
JP21H01934, JP20J23393, JP19H00895, and JP18J22838 and
partly by JST CREST Grant Number JPMJCR19R4, Japan. H.
Yamagishi acknowledges a JSPS Predoctoral Fellowship. J.S.
thanks the support by The Sumitomo Foundation.
CONCLUSIONS
■
We have developed a new class of practical silylating reagents,
sodium silylsilanolates, and confirmed their efficiency for the
delivery of silyl groups in the palladium-catalyzed silylation of
aryl (pseudo)halides. The new silylation method with
silylsilanolates allowed the introduction of a series of silyl
groups including the ones that have been regarded to be
laborious. A good functional group tolerance exhibited under
the conditions proved an applicability to the late-stage
silylation of drugs and complex molecules. Mechanistic studies
with 31P and 19F NMR experiments and DFT calculations
revealed a plausible reaction mechanism for the intramolecular
transfer of the terminal silyl group on a silanolate to the
palladium center, which was assisted by a cluster of silanolates.
These results unveiled a broader potential versatility of sodium
silylsilanolates as reagents for transferring broad silyl groups in
a range of challenging silylating transformations. Development
of other silylsilanolate species and further applications of alkali
metal silylsilanolates in combination with other transition-
metal catalysts will be reported in due course.
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ASSOCIATED CONTENT
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acscatal.1c02733.
Characterization of the products, experimental proce-
dures, and details for NMR experiments and DFT
calculations (PDF)
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AUTHOR INFORMATION
■
Corresponding Authors
Jun Shimokawa − Department of Chemistry, Graduate School
of Science, Kyoto University, Kyoto 606-8502, Japan;
orcid.org/0000-0002-4023-4640; Email: shimokawa@
kuchem.kyoto-u.ac.jp
Hideki Yorimitsu − Department of Chemistry, Graduate
School of Science, Kyoto University, Kyoto 606-8502, Japan;
orcid.org/0000-0002-0153-1888; Email: yori@
kuchem.kyoto-u.ac.jp
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Substitution with Silicon Electrophiles: Catalytic Friedel−Crafts C−H
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Authors
Hiroki Yamagishi − Department of Chemistry, Graduate
School of Science, Kyoto University, Kyoto 606-8502, Japan;
orcid.org/0000-0001-9220-6839
Hayate Saito − Department of Chemistry, Graduate School of
Science, Kyoto University, Kyoto 606-8502, Japan;
orcid.org/0000-0002-4549-7917
Complete contact information is available at:
https://pubs.acs.org/10.1021/acscatal.1c02733
Author Contributions
The manuscript was written through contributions of all
authors. All authors have given approval to the final version of
the manuscript.
Notes
The authors declare no competing financial interest.
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