Highly dispersed Ni2P nanoparticles on N,P-codoped carbon for efficient cross-dehydrogenative coupling to access alkynyl thioethers

Article abstract of DOI:10.1039/c9gc04137k

An ultrafine Ni₂P (a metal-rich interstitial phosphide compound) nanoparticles with a narrow size distribution homogeneously dispersed on N,P-codoped carbon was developed for efficient synthesis of alkynyl thioethers via base- and ligand-free cross-dehydrogenative coupling (CDC) of terminal alkynes and thiols using atmospheric air as the oxidant under mild conditions. A remarkable catalytic performance with good functional group compatibility, broad substrate scope and high stability is accomplished. Pyridinic N atoms are identified as basic sites for facilitating the activation of terminal alkynes via hydrogen bonding interactions and play a key role in the success of this base- and ligand-free CDC reaction.

Full text of DOI:10.1039/c9gc04137k

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DOI: 10.1039/C9GC04137K
COMMUNICATION
Highly Dispersed Ni2P Nanoparticles on N,P-codoped Carbon for
Efficient Cross-Dehydrogenative Coupling to Access Alkynyl
Thioethers
Received 00th January 20xx,
Accepted 00th January 20xx
Tao Song,a Peng Ren,a,b Jianliang Xiao c Youzhu Yuand and Yong Yang* a
DOI: 10.1039/x0xx00000x
[4a,4b]
[6b]
An ultrafine Ni2P (a metal-rich interstitial phosphide compound) tetramethylguanidine (TMG),
triethylamine (TEA),
nanoparticles with narrow size distribution homogeneously triethylenediamine (DABCO)[7b]), which usually cause some
dispersed on N,P-codoped carbon was developed for efficient issues of the formation of unstable intermediates or
synthesis of alkynyl thioethers via cross-dehydrogenative coupling undesirable side-products, and requirement of harsh reaction
(CDC) of terminal alkynes and thiols with base- and ligand-free conditions[3a,7a]
.
using atmospheric air as oxidant under mild conditions. A
remarkable catalytic performance with good compatibility of broad
substrate scope and high stability are accomplished. Pyridinic N is
identified as basic sites for facilitating activation of terminal alkyne
via hydrogen bonding interaction and plays a key role for the
success of this base- and ligand-free CDC reaction.
Previous work:
a) Umpolung strategy
R1 X +
[Cu], ligand, base[2a,2b,3b,3c]
R2
S
M
R2
R1
anhydrous, anaerobic,
low temperature conditions[3a]
S
S
X = Ts, SO3Na,
SR1, halides
NiCl2.dme, 4-CzIPN,
Pyridine, hv [6a]
TMG,[4a,4b] K2CO3,[5]
[Pd], Xantphos, TEA [6b]
R2
R1
X = EBX, halides,
thiophenium salts
S H +
X
R2
R1
Alkynyl thioethers are extremely versatile and essential building
blocks in organic synthesis and intermediates for synthesis of
sulfur-rich functional polymers.[1] Up to now, various methods
have been developed for preparation of alkynyl thioethers,
including (i) umpolung strategy via the prefunctionalization of
either thiols or alkynes to sulfenyl halides,[2] disulfides,[3]or
ethynyl benziodoxolone (EDX) reagents,[4] (alkynyl)-
dibenzothiophenium triflates,[5] haloalkynes[6], followed by the
reaction with the coupling partners (Scheme 1a); (ii)
electrophilic alkynylthio transfer strategy, in which alkyne was
firstly converted to highly active electrophile as an alkynylthio
transfer reagent with subsequent reaction with nucleophiles to
deliver C-S bond compounds (Scheme 1b).[7] In these two
strategies, prefunctionalization process of either terminal
alkynes or thiols is necessary and in the presence of transition-
metal (Pd,[6b] Cu,[2a, 2b, 3a, 3b] Ni[6a]) catalysis assisting with ligands
b) Electrophilic Alkynylthio Transfer strategy
anhydrous, anaerobic,
low temperature conditions[7a]
LG
+
R2
Nu-H
S
R2
Nu
R1
DABCO[7b]
S
S
LG = imidazolium, phthalimide
c) Cross-Dehydrogenative Coupling strategy
RhH(PPh3)4, dppf[9a]
R1
S
or
H
R2
+
H
R2
[Cu], K2CO3
R1SSR1
This work:
R1
molecular oxygen[9b-d]
R2
Ni2P@NPC, DMF, 50oC
1 atm Air atmosphere
R1
S
H +
H
R2
S
Base- and ligand-free, atmospheric air as oxidant, mild conditions
High activity, broad substrate scope Easy separation and recyclable
Scheme 1. Strategies for the synthesis of alkynyl thioethers.
Besides, transition-metal catalyzed cross dehydrogenative
coupling (CDC) of inactivated alkynes with thiols or disulfides
represent the most straightforward and efficient method to
access the alkynyl thioethers as shown in Scheme 1c, which
have been frequently employed for construction of C-X (X = C,
N, O) bonds.[8] However, only sporadic reports are available for
synthesis of C-S bond to date, most likely due to the poison
effect of sulphur atom on metals. In this context, Cu-based
[5]
[6a]
or the mediate of base (K2CO3,
pyridine,
a. Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of
Sciences, Qingdao 266101, P R China. E-mail: yangyong@qibebt.ac.cn
b. University of Chinese Academy of Sciences, Beijing 100049, P R China
c. Department of Chemistry, Liverpool University, Liverpool L69 7ZD, UK.
d. State Key Laboratory of Physical Chemistry of Solid Surfaces, National Engineering
Laboratory for Green Chemical Production of Alcohols-Ethers-Esters, College of
Chemistry and Chemical Engineering, Xiamen 361005, P R China.
† Footnotes relating to the title and/or authors should appear here.
Electronic Supplementary Information (ESI) available: [details of any supplementary
information available should be included here]. See DOI: 10.1039/x0xx00000x
catalysts have been successfully applied for such
transformation with one exception of using precious Rh
complex.[9a] Nonetheless, the assistance of sophisticated and
a
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expensive organic ligands (dppf)[9a], and bases (K2CO3)
the presence of molecular oxygen atmosphere are necessary for TEM) images (Figure 1b and c) of the catalyst Ni2P@NPC-800
the success of the reaction.[9b-d] More worse, in these cases, disclose that the small Ni2P NPs with narrow size distribution
poor compatibilities of functional groups, low selectivity to the (3.2 ± 0.7 nm) are uniformly dispersed on the graphitic carbon
targeted products, and difficulty of product-catalyst separation materials. High-angle annular dark-field scanning transmission
significantly limited their practical applications. Therefore, the electron microscopy (HAADF-STEM) (Figure S1a) with energy-
synthesis of alkynyl thioethers from the coupling of alkynes with dispersive X-ray (EDX) maps (Figure S1b-1f) clearly show that a
Journal Name
[9b-d]
in
High-resolution transmission electron microscopy (HR-
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DOI: 10.1039/C9GC04137K
thiols or disulfides still remains a significant challenge.
homogeneous distribution of Ni, P, N, C and O through the
Herein, we developed a stable inexpensive heterogeneous entire carbon framework. Powder X-ray diffraction (PXRD)
metal-rich interstitial nickel phosphide catalyst (denoted as pattern (Figure 1d) discloses the formation of single Ni2P phase
Ni2P@NPC-800), in which ultrafine Ni2P nanoparticles (NPs) on graphitic carbon, in good consistency with HR-TEM
with narrow size distribution were homogeneously dispersed observation. N 1s and P 2p XPS analysis (Figure 1f and 1g) verify
on N,P-codoped biomass-derived porous carbon. The resultant that N and P atoms were co-incorporated into the carbon
catalyst Ni2P@NPC-800 shows excellent catalytic activities for framework. High resolution deconvolution analysis discloses
synthesis of alkynyl thioethers via cross dehydrogenative that N atoms presented in pyridinic-, pyrrolic-, graphitic-, and
coupling of alkynes and thiols using air as the sole oxidant with oxidized-N species, while P-C, P-O, and Ni-P species were
base- and ligand-free under mild conditions (Details of formed for P atoms. Ni 2p XPS (Figure 1e) further confirm the
comparison with previous works see Table S2). To the best of formation of metal-rich interstitial Ni2P NPs, while a certain
our knowledge, this is the first case for expedient synthesis of amount of Ni2+ species were also detected most likely due to
alkynyl thioethers via cross dehydrogenative coupling of the inevitable partial oxidation of Ni2P NPs on the surface. N2
alkynes and thiols catalyzed by a stable Ni catalyst. High adsorption/desorption measurements demonstrate that the
catalytic activity and excellent selectivity accompanying with catalyst Ni2P@NPC-800 prepared in this strategy possesses
good tolerance of functional groups, broad substrate scopes hierarchically micro-, meso-, and macro-pores with high specific
and strong stability were accomplished under mild reaction surface area and large pore volume as shown in Figure S3 and
conditions, highlighting the practicability of this protocol for Table S1.
With the as-prepared catalysts in hand, we initiated our
investigation using phenylacetylene (1a) and para-
chlorobenzenethiol (3a) as coupling partners to test the
feasibility as shown in Table 1. Initially, we performed the
reaction in the presence of Ni2P@NPC-800 (8 mol% of Ni) as a
catalyst, 10 mol% K2CO3 as a base at 70oC in DMF (0.1 M) under
air atmosphere, full conversion of 1a with 77% GC yield of the
targeted product 2a was achieved accompanying with the
formation of diene (4a) in 23% after 6 h (Table 1, entry 1). The
GC yield to 2a could be enhanced to 84% by increasing the ratio
of 1a/1b from 1/1.1 to 1/1.5 (entry 2), while no obvious effect
was observed with further increasing the ratio to 1/2 (entry 3).
Delightfully, we found that the GC yield to 2a was markedly
improved to 95% together with 5% of 4a when the reaction was
carried out in the absence of a base under otherwise identical
conditions. Subsequently, other factors, such as solvents
(entries 5-7), reaction temperatures (entries 9, 10), and reaction
times (entries 8), were intensively investigated for the effect on
reaction efficiency. The reaction in DMSO as the solvent showed
comparable reactivity to that in DMF (entry 5), whereas a
considerable lower reactivity with the formation of 4a as major
product was observed in THF or CH3CN as solvent (entries 6 and
7). The reactivity as a function of reaction time showed that the
reaction could complete with 4 h at 50oC (entry 8). Besides, the
reaction temperature lowered from 70 to 50oC had a negligible
effect on reactivity and selectivity to 2a (entry 9), however, a
further decrease to room temperature led to a significant drop
in reactivity (entry 10). For comparison, the catalyst Ni2P@NPC-
700 showed a relatively lower activity, while a comparable
reactivity was observed for the catalyst Ni2P@NPC-900 (entries
11 and 12), compared with that of Ni2P@NPC-800 under
otherwise identical conditions. In addition, a set of control
experiments either in the absence of a catalyst or air, or in the
presence of NPC-800 without Ni loading or nickel salts as the
sole catalyst, all gave negligible or no reactivity (entries 13-16).
accessing important building blocks alkynyl thioethers.
Ultrafine and highly dispersed Ni2P NPs on biomass-derived
porous carbon was prepared in a sequential hydrothermal and
pyrolysis process according to our previous reports as shown in
Figure 1a (See details in the Supporting Information).[10] The as-
prepared catalysts were denoted as Ni2P@NPC-T, where T
represents the pyrolysis temperature. The Ni content in the
catalysts was determined to be 3.05-4.96 wt% by the coupled
plasma optical emission spectrometry (ICP-OES) (Table S1).
Figure 1. (a) Illustration for preparation of catalyst; (b), (c) HR-TEM and size
distribution of Ni2P@NPC-800; (d) Powder XRD pattern of Ni2P@NPC-800; (e-
g) High-resolution XPS spectra of Ni 2p, N 1s, P 2p of Ni2P@NPC-800.
2 | J. Name., 2012, 00, 1-3
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From these observations, we can safely conclude that the
catalyst Ni2P@NPC-800 and air atmosphere were indispensable
for the success of the reaction.
hydroxyl (1s and 1t) group and conjugated with C=C bond (2u),
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are suitable for the reaction with formDaOtiIo: n10.o10f3t9h/Ce9GtaCr0g4e1t3e7dK
alkynyl thioethers in 72-82% yields. Moreover, other
substituted benzenethiols (3p and 3q) or alkyl thiols (3w and 3x)
also work well to construct the C-S bonds in decent to high
yields. Remarkably, more challenging coupling of aliphatic
terminal alkynes with aliphatic thiols was also realized with this
protocol to deliver their corresponding alkynyl thioether (2y
and 2z) in satisfactory yields.
Table 1. Optimization of reaction conditions.a
Ni2P@NCP-800
S
(8 mol%)
SH
+
+
Cl
Base, DMF,
70oC, 6 h, Air
Cl
2
1a
3a
2a
4a
GC yield [%]b
Entry
1a/1b
(molar ratio)
Solvent
T
Conv.
[%]b
100
[oC]
Subsequently, we investigated the recyclability of the catalyst
Ni2P@NPC-800 for the benchmark reaction under the optimized
conditions. The catalyst has been used 6 times consecutively
with negligible changes of activity, indicating the strong stability
(Figure S7). Separation of the solution from the catalyst at
approximately 45% conversion of 1a via hot filtration stopped
the formation of 2a, suggesting that irreversibly leached nickel
species (if any) have a minor contribution to the reactivity
(Figure S8). Taken together, all the results strongly indicate the
intrinsic role of the heterogeneous Ni2P@NPC-800 in catalysis.
2a
77
4a
1c
1/1.1
DMF
DMF
DMF
DMF
DMSO
THF
70
70
70
70
70
70
70
70
50
RT
50
50
50
50
50
50
23
2c
1/1.5
1/2
100
100
100
100
61
84
87
95
91
11
9
16
17
5
3c
4
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
1/1.5
5
4
6
50
68
4
7
CH3CN
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
77
8d
9d
10
11e
12f
13g
14h
15i
16j
100
100
31
96
95
13
40
93
0
5
Table 2. Substrate scopes for synthesis of alkynyl thioethers.a
Ni2P@NCP-800
(8 mol%)
18
13
7
S
+
SH
R2
R2
R1
R1
DMF, 50oC, 4h, Air
53
1
3
2
100
0
Ar
S Ar
S
S
0
S
S
21k
0
0
0
Cl
Cl
Cl
Cl
Cl
F
Cl
Br
2a 91%
S
2b 94%
S
2c 90%
2d 87%
S
0
0
S
0
0
0
Cl
Cl
Cl
MeO
OMe
2h 93%
2f 82%
2g 97%
S
2e 93%
S
aReaction conditions: phenylacetylene (0.2 mmol), catalyst (8 mol% of Ni),
Solvent (2 mL), air atmosphere, bDetermined by GC based on consumption of
phenylacetylene. cK2CO3 (10 mol%) was used. d4 h instead of 6 h. eNi2P@NPC-
S
S
Cl
Cl
Cl
Cl
N
OMe
F3C
NH2
f
700, 4 h. Ni2P@NPC-900, 4 h. gNPC-800, 4 h. hUnder Ar atmosphere, 4 h.
2j 77%
S
2k 71%
S
2l 77%
S
2i 81%
iNi(OAc)2 instead of Ni2P@NPC-800,
4 4
h. jNo catalyst, h. k(4-
S
chlorophenyl)(styryl)sulfane was detected by GC-MS.
Cl
Cl
Cl
F
S
N
MeO2C
2m 74%
S
2p 91%
S
2n 61%
2o 80%
After identifying the optimized reaction conditions, we then
explored the generality of this protocol for the synthesis of
alkynyl thioethers, the results are compiled in Table 2. Firstly, a
set of functional groups substituted phenylacetylenes were
tested to couple with 3a under the optimized conditions.
Phenylacethylenes bearing either electron-donating groups (-
Me, -OMe, -NH2, -NMe2) or electron-withdrawing groups (-CF3,
-CO2Me) were efficiently coupled to give their corresponding
alkynyl thioethers in 71-97% yields. Comparatively, a relatively
higher yield was achieved for the phenylacetylenes with
electro-donating substituents (1e, 1g, 1h) than those with
electro-withdrawing ones (1l and 1m). The steric effect was
clearly observed, for example, otho-methyl (1f) or methoxyl (1i)
substituted phenylacetylene behaved a lower reactivity than
that in para- or meta-position. Halogen substituents (F, Cl, and
Br) are compatible with the present conditions, affording their
corresponding alkynyl thioethers in 87-94% yields. Of note, the
amino-substituted phenylacetylene (1j and 1k), which are
problematic substrates in previously reported protocols due to
the easy oxidation and coordination with metal centers with N
atom,[12] could also be transformed into alkynyl thioethers in
77% and 71% yields, respectively. Besides, heterocyclic
substituted acetylenes, such as 1n and 1o, were also smoothly
converted into the desired products in good yields. Next,
aliphatic terminal alkynes (1r-1v), including those containing
OH
OH
S
S
Cl
Cl
Cl
Cl
2q 93%
2t 79%
2r 77%
S
2s 72%
S
Alkyl
S Ar
Cl
2u 82%
2v 80%
Ar
S
Alkyl
S
Alkyl
S
Alkyl
S
S
S
2w 67%
2x 61%
2y 52%
2z 57%
aReaction conditions: alkyne (0.2 mmol), thiol (0.3 mmol) Ni2P@NPC-800 (8
mol% of Ni), DMF (2 mL), air atmosphere, 50oC, 4h, bIsolated yields were
reported.
To gain insight into the reaction pathway, a set of control
experiments were carried out. The compounds distribution for
the benchmark reaction as a function of reaction time under the
optimized reaction conditions (Figure 2) reveals that 1,2-bis(4-
chlorophenyl)disulfane (5a) was rapidly produced with the
quick consumption of 3a at the initial reaction stage (within 1
h), while only small amount of the desired product 2a was
generated in this period. Subsequently, the gradual formation
of 2a via the coupling of 1a and 5a dominated the reaction till
complete consumption of 1a. So we assume that 5a most likely
acts as the real intermediate for the coupling, which has been
frequently employed for the coupling of alkynes to construct C-
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
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Journal Name
S bond.[3] To prove this assumption, p-chlorobenzenethiol (3a)
was subjected into the standard conditions (Scheme 2 eq. a),
and 5a was obtained in 99% yield determined by GC. More
interestingly, 3a could be quantitatively converted into 5a in the
absence of the catalyst Ni2P@NPC-800 under otherwise
identical conditions (Scheme 2 eq. b). Furthermore, the
coupling reaction of phenylacetylene (1a) with 5a instead of 3a
as coupling partner under the standard conditions also gave a
comparable yield (93% vs 95% in Table 1, entry 9) to 2a (Scheme
2 eq. c). Taken all results together, it was convinced that the
coupling reaction indeed proceeds via the first formation of
disulfane as a nucleophile for subsequent reaction with alkyne
to produce the desired alkynyl thioether.
Previous studies show that a base (inorganic or organic) is
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basically required in CDCs to initiate the DreOaI:c1t0io.1n03v9i/aC9aGctCiv0a41t3in7Kg
either thiol or terminal alkyne.[9b-9e] However, this is not the
case in our present catalysis, and outstanding catalytic
performance was achieved in the absence of base as shown in
Table 2. We further attempted to elucidate the role of the
catalyst. Control experiments discussed above reveal that thiol
could be readily oxidized into disulfane without catalyst under
1
air in DMF at 50oC (Scheme 2, eq. a). So, H NMR experiments
were conducted to identify how the catalyst activate the
terminal alkyne. Taking phenylacetylene (1a) as an example, an
obvious chemical shift of terminal alkynyl hydrogen to high field
was observed when 1a was added into the CDCl3 solution
containing the Ni2P@NPC-800 for 10 min, which might due to
the hydrogen bonding interaction between alkynyl hydrogen
and Ni2P NPs or N atoms doped in carbon.[13] Similar but with a
slightly lower shift was also observed using NPC-800 instead of
Ni2P@NPC-800 with same treatment. In sharp contrast, no
visible chemical shift was detected using activated carbon (AC)
without N-doping instead, indicating that N atoms did play a
role to interact with alkyne. As previously reported,[10,14]
N
atoms, specifically pyridinic species, in N-doped carbon could
serve as basic sites to interact and/or activate some molecules.
To prove it, pyridine, as mimicking N species in carbon, was
mixed with 1a in CDCl3 solution, almost identical shift to that in
NPC-800 was observed, further confirming the role of N atoms
as basic sites to interact with alkyne in the catalyst Ni2P@NPC-
800.[10e,14] In addition, no reactivity was obtained when the
benchmark reaction was performed under the optimized
conditions, but with addition of stoichiometric amount of H3PO4
as a poisoning agent to deactivate N sites (Scheme 2, eq. d).
Therefore, these experimental results clearly disclose that the
key role of N atoms doped in carbon is as basic sites to activate
alkyne via hydrogen bonding interaction, thereby facilitating
the reaction.
Figure 2. The compounds distribution for the benchmark reaction as a
function of reaction time under the optimized reaction conditions.
Cl
Ni2P@NPC-800
Cl
Cl
SH
SH
S
(a)
(b)
DMF, 50oC, 4 h, Air
>99% GC yield
S
3a
5a
Cl
Cl
Cl
w/o Ni2P@NPC-800
S
S
DMF, 50oC, 4 h, Air
>99% GC yield
5a
3a
Cl
+
S
Ni2P@NPC-800
S
(c)
(d)
S
Cl
Cl
DMF, 50oC, 4h, Air
2a
1a
Cl
5a
(1.5 eq.)
93% yield
S
Cl
Ni2P@NPC-800
+
DMF, 50oC, 4h, Air
SH
2a
1 eq. H3PO4
1a
5a
0 % yield
0% conversion
(1.5 eq.)
Scheme 2. Control experiments.
Scheme 3. Proposed mechanism for the synthesis of alkynyl thioethers via
CDC strategy.
Taking all control experiments and our previous works into
account, we proposed a plausible mechanism for the reaction
as presented in Scheme 3. Initially, thiol was rapidly converted
into disulfane in the presence of air atmosphere, which
underwent the oxidative addition to Ni2P NPs to form the
intermediates.[9a, 9e] Next, the terminal alkyne was adsorbed and
activated via hydrogen bonding between N atoms in carbon and
terminal alkynyl hydrogen. In this step, N atoms as basic sites
Figure 3. 1H NMR experiments for study of the role of N-doping.
4 | J. Name., 2012, 00, 1-3
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not only boost the selective absorption of alkyne on the surface
of catalyst, but also activate Csp-H bond of terminal alkyne.[10, 13]
Finally, the desired product was generated via reductive
elimination and simultaneously completed the entire catalytic
circle.
3
4
(a) T. Reeves, K. Camara, Z. S. Han, Y. Xu, H. Lee, VCie.wAA.rBticulesaOcnclinae,
C. H. Senanayake, Org. Lett., 2014, 16, D1O19I:61;0(.1b0)3K9/.CK9aGnCe0m41o3t7oK,
S. Yoshida, T. Hosoya, Org. Lett., 2019, 21, 3172; (c) W. Wang,
X. Peng, F. Wei, C.-H. Tung, Z. Xu, Angew. Chem. Int. Ed., 2016,
55, 649.
(a) R. Frei, J. Waser, J. Am. Chem. Soc. 2013, 135, 9620; (b) R.
Frei, M. D. Wodrich, D. P. Hari, P.-A. Borin, C. Chauvier, J.
Waser, J. Am. Chem. Soc., 2014, 136, 16563.
Conclusions
5
6
B. Waldecker, F. Kraft, C. Golz, M. Alcarazo, Angew. Chem., Int.
Ed., 2018, 57, 12538.
In conclusion, a stable heterogeneous Ni2P nanoparticles
on N,P-codoped carbon was developed for the synthesis of
alkynyl thioethers via the cross-dehydrogenative coupling of
alkynes and thiols under base- and ligand-free conditions. A
broad range of alkynes and thiols could be efficiently coupled
into their corresponding alkynyl thioethers in good to high
yields with good tolerance of various functional groups. The
catalyst can be readily recovered for successive recycle. N-
dopants in the catalyst was identified to play a key role for the
success of the reaction. To the best of our knowledge, this is the
(a) J. Santandrea, C. Minozzi, C. Cruche, S. K. Collins, Angew.
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7
8
first case to access alkynyl thioethers catalyzed by
a
heterogeneous stable Ni-based catalyst, and also represents
one of the most straightforward and efficient method for
synthesis of alkynyl thioethers in
environmentally friendly manner.
a cost-effective and
9
(a) M. Arisawa, K. Fujimoto, S. Morinaka, M. Yamaguchi, J. Am.
Chem. Soc., 2005, 127, 12226; (b) Z. Fang, W. He, M. Cai, Y. Lin,
H. Zhao, Tetrahedron Lett., 2015, 56, 6463; (c) Y. Yang, W.
Dong, Y. Guo, R. M. Rioux, Green Chem., 2013, 15, 3170; (d) L.
W. Bieber, M. F. da Silva, P. H. Menezes, Tetrahedron Lett.,
2004, 45, 2735.
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
10 (a) Z. Ma, T. Song, Y. Yuan, Y. Yang, Chem. Sci., 2019, 10, 10283.
(b) Y. Duan, X. Dong, T. Song, Z. Wang, J. Xiao, Y. Yuan, Y. Yang,
ChemSusChem, 2019, 12, 4636; (c) T. Song, P. Ren, Y. Duan, Z.
Wang, X. Chen, Y. Yang, Green Chem., 2018, 20, 4629-4637; (d)
Y, Duan, T. Song, X. Dong; Y. Yang, Green Chem., 2018, 20, 2821
-2828; (e) X. Dong, Z. Wang, Y. Duan, Y. Yang, Chem. Commun.,
2018, 54, 8913; (f) Y. Duan, G. Ji, S. Zhang, X. Chen, Y. Yang,
Catal. Sci. Technol., 2018, 8, 1039; (g) G. Ji, Y. Duan, S. Zhang,
B. Fei, X. Chen, Y. Yang, ChemSusChem, 2017, 10, 3427.
11 (a) L.-A. Stern, L. Feng, F. Song, X. Hu, Energy Environ. Sci.,
2015,
The authors would like to acknowledge the financial support
from the Key Technology R&D Program of Shandong Province
(2019GGX102075), Open Projects of State Key Laboratory of
Physical Chemistry of the Solid Surface (Xiamen University) (No.
201808), and the 13th-Five Key Project of the Chinese Academy
of Sciences (Grant No. Y7720519KL). Y.Y also thanks the support
from the Royal Society (UK) for a Newton Advanced Fellowship
(NAF\R2\180695).
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526, 1; (d) J. L. Fiorio, R. V. Goncalves, E. Teixeira-Neto, M. A.
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View Article Online
DOI: 10.1039/C9GC04137K
An Ni2P nanoparticles on N,P-codoped carbon was developed
for efficient synthesis of alkynyl thioethers via cross-
dehydrogenative coupling (CDC) strategy under base- and
ligand-free, air as oxidant conditions.
6 | J. Name., 2012, 00, 1-3
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