Synthesis and catalytic activity of N-heterocyclic silylene (NHSi) iron (II) hydride for hydrosilylation of aldehydes and ketones

Article abstract of DOI:10.1002/aoc.6286

A novel silylene supported iron hydride [Si, C]FeH (PMe₃)₃ (1) was synthesized by C (sp³)-H bond activation with zero-valent iron complex Fe (PMe₃)₄. Complex 1 was fully characterized by spectroscopic methods and single crystal X-ray diffraction analysis. To the best of our knowledge, 1 is the first example of silylene-based hydrido chelate iron complex produced through activation of the C (sp³)?H bond. It was found that complex 1 exhibited excellent catalytic activity for hydrosilylation of aldehydes and ketones. The catalytic system showed good tolerance and catalytic activity for the substrates with different functional groups on the benzene ring. It is worth mentioning that, the experimental results showed that both ketones and aldehydes could be reduced in good to excellent yields under the same catalytic conditions. Based on the experiments and literature reports, a possible catalytic mechanism was proposed.

Full text of DOI:10.1002/aoc.6286

Received: 22 February 2021
DOI: 10.1002/aoc.6286
Revised: 11 April 2021
Accepted: 25 April 2021
F U L L P A P E R
Synthesis and catalytic activity of N-heterocyclic silylene
(NHSi) iron (II) hydride for hydrosilylation of aldehydes
and ketones
Xinyu Du1 | Xinghao Qi1 | Kai Li1 | Xiaoyan Li1 | Hongjian Sun1
Olaf Fuhr2 | Dieter Fenske2
|
1School of Chemistry and Chemical
A novel silylene supported iron hydride [Si, C]FeH (PMe3)3 (1) was synthesized
by C (sp3)-H bond activation with zero-valent iron complex Fe (PMe3)4. Com-
plex 1 was fully characterized by spectroscopic methods and single crystal X-ray
diffraction analysis. To the best of our knowledge, 1 is the first example of
silylene-based hydrido chelate iron complex produced through activation of the
C (sp3)ꢀH bond. It was found that complex 1 exhibited excellent catalytic activ-
ity for hydrosilylation of aldehydes and ketones. The catalytic system showed
good tolerance and catalytic activity for the substrates with different functional
groups on the benzene ring. It is worth mentioning that, the experimental
results showed that both ketones and aldehydes could be reduced in good to
excellent yields under the same catalytic conditions. Based on the experiments
and literature reports, a possible catalytic mechanism was proposed.
Engineering, Key Laboratory of Special
Functional Aggregated Materials, Ministry
of Education, Shandong University, Jinan,
China
2Institut für Nanotechnologie (INT) und
Karlsruher Nano-Micro-Facility (KNMF),
Karlsruher Institut für Technologie (KIT),
Eggenstein-Leopoldshafen, Germany
Correspondence
Hongjian Sun, School of Chemistry and
Chemical Engineering, Key Laboratory of
Special Functional Aggregated Materials,
Ministry of Education, Shandong
University, Shanda Nanlu 27, Jinan
250100, China.
Email: hjsun@sdu.edu.cn
K E Y W O R D S
Funding information
aldehyde, hydrosilylation, iron hydride, ketone, silylene
National Natural Science Foundation of
China, Grant/Award Numbers: 21971151,
21572119; Natural Science Foundation of
Shandong Province, Grant/Award
Numbers: ZR2019ZD46, ZR2019MB065
1 | INTRODUCTION
found that NHSi supported transition metal complexes[2]
as catalysts could be used in the Kumada reaction,[3]
As carbene analogue, silylene has strong σ-donating/
π-backdonation ability and unique stereoscopic charac-
teristics. The transition metal complexes supported by
silylene exhibit rich diversity in coordination mode, spa-
tial structure, and electronic configuration.[1] Therefore,
silylene metal complexes have important value in orga-
nosilicon chemistry and applied chemistry. In the past
20 years, the types of N-heterocyclic silylene (NHSi) have
been greatly enriched, and the silylene chemistry has
made significant progress in the construction of metal
complexes, activation of small molecules, homogeneous
catalysis, nitrogen reduction, and other fields. It has been
Sonogashira reaction,[4] reduction of amides,[5]
hydrosilylation
of
aldehydes
and
ketones,[6]
hydrosilylation of olefins,[7] and C-H borylation reac-
tion.[8] Base metal iron complexes have gradually rep-
laced precious metal complexes for a variety of catalytic
reactions. Driess reported the first silylene iron complex
and found that this complex could catalyze the
hydrosilylation of ketones.[9] Huang successfully realized
the hydrosilylation of ketones with iron silylene complex
as catalyst.[10] Recently, Cui's research group published
the first NHSi iron nitrogen complex, and proved that
this complex has a good catalytic effect for nitrogen
Appl Organomet Chem. 2021;e6286.
wileyonlinelibrary.com/journal/aoc
© 2021 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.6286

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DU ET AL.
SCHEME 1 Synthesis of NHSi hydrido Fe (II) complex 1
reduction.[11] However, there are still few examples on
the synthesis and application of silylene Fe complexes.
Because metal hydride as catalyst or intermediate par-
ticipates in many catalytic reactions, it has been widely
concerned in organometallic chemistry.[12,13] In recent
years, our group has also been devoted to metal hydride
chemistry, and we synthesized various iron hydrides and
studied the catalytic activity of these hydrides for differ-
ent reactions.[14] Due to the diversity of the coordination
chemistry of silylenes, we introduce silylenes into iron
hydrides, and expect these hydrides to have special chem-
ical properties and applications.
Driess realized the catalytic hydrosilylation of carbonyl
compounds with NHSi iron complex as catalyst for the first
time.[9] We synthesized silylene iron hydride by activating
the C (sp2)-H bond on the pyridine ring to catalyze hydro-
boration of carbonyl compounds under mild conditions.[15]
Recently, we reported a bis-silylene iron hydride obtained
by activation of C (sp3)-H bond.[16] It was proved that this
iron hydride could effectively catalyze nitrogen reduction.
In this paper, chelated silylene iron hydride 1 was syn-
thesized by activation of C (sp3)-H bond. It was found that
complex 1 has good catalytic activity for hydrosilylation of
both aldehydes and ketones. In particular, it is worth men-
tioning that complex 1 has almost the same catalytic activ-
ity for ketones and aldehydes under the same conditions.
Generally, for the same catalyst the conditions for ketone
reduction are more severe than those for aldehyde reduc-
tion. In our system, ketones and aldehydes can be reduced
under the same conditions. In comparison with the publi-
shed work, our catalytic system has the advantages of lower
FIGURE 1 The hydrido resonance of 1
FIGURE 2 Molecular structure of 1. The
thermal ellipsoids are displayed at the 50%
probability level, and most of the hydrogen
atoms are omitted for clarity. Selected bond
lengths (Å) and angles[deg]: Fe1-H1 1.50(4),
Fe1-P1 2.1799(9), Fe1-P2 2.1792(10), Fe1-P3
2.1928(10), Fe1-Si1 2.1641(9), Fe1-C2 2.141(4),
Si1-O1 1.666(2); P2-Fe1-H1 172.4(16), Si1-Fe1-P1
96.97(3), P1-Fe1-P3 96.85(4), C2-Fe1-P3 90.33
(14), C2-Fe1-Si1 74.85(12), C1-O1-Si1 112.75(19)

DU ET AL.
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SCHEME 2 Pathway from L1 to complex 1
TABLE 1 Optimization of catalytic
conditions for aldehydesa
entry
loading
2%
silane
solvent
THF
temp (ꢁC)
time (hr)
Conv. (%)b
1
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
PhSiH3
60
60
50
60
60
60
60
60
60
60
60
60
60
60
60
6
8
8
8
8
8
8
8
8
8
8
8
8
8
8
86
99
88
77
64
23
12
0
2
2%
THF
3
2%
THF
4
1%
THF
5
2%
THF
6
2%
Ph2SiH2
THF
7
2%
Ph3SiH
THF
8
2%
Et3SiH
THF
9
2%
Me (EtO)2SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
THF
80
50
89
74
90
68
0
10
11
12
13
14
15
2%
Toluene
Dioxane
DMF
DME
Benzene
THF
2%
2%
2%
2%
0%
aCatalytic reaction condition: Benzaldehyde (1.0 mmol), Hydrosilane (1.2 mmol) and Catalyst (2% mmol) in
2 ml THF, T ꢁC, t hr.
bDetermined by GC with dodecane as internal standard.

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DU ET AL.
TABLE 2 Products of hydrosilylation of aldehydes to alcoholsa,b
aCatalytic reaction conditions: Aldehyde (1 mmol), (EtO)3SiH (1.2 mmol), Catalyst (2 mol%) in 2 mL THF, 60ꢁC, 8 hr.
bIsolated yield.
TABLE 3 Optimization of catalytic reaction conditions for ketonesa
Entry
Loading
2%
Silane
Solvent
THF
Temp (ꢁC)
Time (hr)
Conv. (%)b
1
2
3
4
5
6
7
8
9
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
(EtO)3SiH
60
60
50
60
60
60
60
60
60
8
6
8
8
8
8
8
8
8
98
80
90
46
75
88
95
91
89
2%
THF
2%
THF
1%
THF
2%
C6H6
2%
Toluene
DMF
2%
2%
Dioxane
None
2%
aCatalytic reaction condition: Acetophenone (1.0 mmol), (EtO)3SiH (1.2 mmol) and Catalyst (2% mmol) in 2 ml THF, 60ꢁC, t hr.
bDetermined by GC with n-dodecane as an internal standard.

DU ET AL.
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catalyst loading, lower reaction temperature, shorter reac-
tion time and no additives for ketone substrates. We have
made a preliminary study on the catalytic mechanism.
of 1 the hydrido resonance is situated at ꢀ15.96 ppm as a
dddd signal caused by the H, P-coupling (Figure 1).
Because of the existence of isomers in the solution, it is
difficult to identify other hydrogen signals. The multi-
plets between 0.90–2.08 ppm belong to the three PMe3
ligands, two tBu, two Me groups, and methylene hydro-
gen. Five aromatic hydrogens are registered between 7.24
and 7.95 ppm as multiplets. The 31P NMR of 1 indicates
that two multiplets for PMe3 ligands are positioned at
19.2–19.6 and 21.2–21.8 ppm in the integral of 1: 2. In the
29Si NMR spectrum of 1, the signal at 53.3 ppm is typical
for the coordinated silylene ligands[15,16] while the free
ligand L1 has the Si resonance at ꢀ5.0 ppm.[17] The
downfield shift is caused by the Si coordination.
Single crystals of 1 suitable for X-ray diffraction analysis
were obtained from n-pentane at ꢀ20ꢁC. 1 has a distorted
octahedral geometry around the iron atom (Figure 2). The
axial direction P2-Fe1-H1 (172.4[16]ꢁ) is almost perpendicu-
lar to the equatorial plane determined by [P1, Si1, Fe1, C2,
P3]. The sum of the bond angles of the four coordination
2 | RESULTS AND DISCUSSION
2.1 | Synthesis of silylene chelate iron
hydride 1
When L1 was mixed with zero valent iron complex Fe
(PMe3)4 in THF, the color of reaction solution gradually
changed from yellow to red (Scheme 1). After simple
work-up, silylene chelate iron hydride 1 as red single
crystals was separated from its n-pentane extract in 70%
yield. On the one hand, silylene Si coordinates with Fe
atom; on the other hand, a chelating five-membered ring
is formed through the activation of the C (sp3)-H bond of
the tert-butoxyl group.
In the IR spectrum of 1 the typical signal of the Fe-H
1
bond is located at 1860 cmꢀ1. In the H NMR spectrum
TABLE 4 Products of hydrosilylation of aromatic ketones to alcoholsa,b
aCatalytic reaction conditions: Aldehyde (1 mmol), (EtO)3SiH (1.2 mmol), Catalyst (2 mol%) in 2 ml THF, 60ꢁC, 8 hr.
bIsolated yield.

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DU ET AL.
bonds in the equatorial plane is 359.0ꢁ with a little deviation
of 360ꢁ. The bond length of Fe1-H1 bond (1.50[4] Å) is
within the normal range of Fe-H bonds.[18] The bond length
of Fe1-P3 (2.1928[10] Å) is longer than that of Fe1-P1
(2.1799[9] Å) and Fe1-P2 (2.1792[10] Å) due to the strong
trans-influence of the Si atom. The bond length of Fe1-Si1
bond (2.1641[9] Å) is comparable to those of the reported
silylene iron complexes.[15,16,19,20]
For the mechanism of the formation of complex
1 (Scheme 2), the substitution of PMe3 ligand with ligand
L1 is the first step. In intermediate A, the coordination of
Si decreases the distance between the central Fe and the
C-H bond. The oxidative addition of the C-H bond at the
electron-rich Fe center affords the final complex 1 with
the formation of the chelate ring. To our knowledge, 1 is
the first example of silylene-based chelate hydrido iron com-
plex produced through activation of the C (sp3)ꢀH bond.
alcohols.[12b] Due to the steric hindrance, it is more
difficult to activate ketones than to activate aldehydes
and the reaction conditions for activating ketones are
more stringent. Therefore, how to improve the conver-
sion of ketone is a subject worthy of exploration.
Benzaldehyde as a template substrate was selected to
explore the hydrosilylation conditions (Table 1). The con-
version could reach 99% at 60ꢁC for 8 hr with 2 mol%
1 as catalyst and (EtO)3SiH as hydrogen source (entry
2, Table 1). When the reaction time was shortened to
6 hr, the conversion of the reaction decreased to 86%
(entry 1, Table 1). When the reaction temperature was
reduced to 50ꢁC or the catalyst loading decreased to
1 mol%, the conversion of the reaction decreased to 88%
and 77% respectively (entries 3–4, Table 1). (EtO)3SiH
has the best catalytic effect compared with other silanes,
such as PhSiH3, Ph2SiH2, Ph3SiH, Et3SiH, and Me
(EtO)2SiH (entries 5–9, Table 1). When the reaction was
carried out in different solvents (THF, toluene, dioxane,
DMF, DME, and benzene), THF was the best reaction
medium (entries 2 and 10–14, Table 1). Without catalyst
1, no conversion was observed (entry 15, Table 1). There-
fore, the optimal reaction conditions are as follows: 2 mol
% catalyst, 60ꢁC, THF, 8 hr (entry 2, Table 1).
2.2 | Catalytic activity of complex 1 for
hydrosilylation of carbonyl compounds
The conversion of aldehydes and ketones into alcohols by
hydrosilylation is an important way to synthesize
SCHEME 3 Chemoselective Hydrosilylation Reactionsa,b. aCatalytic reaction condition: Catalyst (2 mol%) in 2 ml THF, 60ꢁC, 8 hr.
bDetermined by GC with n-dodecane as an internal standard

DU ET AL.
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Under the optimized conditions, benzaldehyde sub-
further shortened to 6 hr, the conversion was reduced to
80% (entry 2, Table 3). When the reaction temperature
was reduced to 50ꢁC, the conversion was 90% (entry
3, Table 3). When the catalyst loading was reduced to
1 mol%, the conversion was only 46% (entry 4, Table 3).
At the same time, when the reaction solvent was changed
to benzene, toluene, DMF, dioxane or without solvent,
the conversion decreased to varying degrees (entries 5–9,
Table 3). Therefore, it can be concluded that the opti-
mized conditions for ketone and aldehyde substrates are
the same (entry 1, Table 3).
strates with different substituents were expanded
(Table 2). The aromatic substrates (2b, 2c, 2d, 2e and 2g)
with different functional groups in different positions on
the phenyl ring have good yields (93%–95%). For sub-
strate (2f) with electron donating group (such as
methoxyl) good yield (77%) could also be achieved. The
yield with 1-naphthaldehyde substrate (2h) is 81%. For
cinnamaldehyde substrates (3a and 3b), the C=O bond
was selectively reduced while the C=C bond did not
react. The yield with α-hexylcinnamaldehyde with long
branched chain could reach 93% yield.
It was found that the catalytic system has good uni-
versality for the ketone substrates (Table 4). The aromatic
ketones (4b, 4c, 4f, 4g, 4e, 4d, and 4h) containing
different functional groups (such as halogen, nitrile, and
In general, it is more difficult to activate ketones than
aldehydes. Surprisingly, under the optimal conditions of
aldehydes, 99% conversion of acetophenone could also be
achieved (entry1, Table 3). When the reaction time was
methoxy)
have
good
yields
(90%–97%).
For
SCHEME 4 Proposed catalytic mechanism

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DU ET AL.
2-acetonaphthalene (4j) the yield was 96%. For N-
heterocyclic compound (2-acetylpyridine, 4i) 95% yield
could be reached. At the same time, the change of sub-
stituent position has little effect on the catalytic reaction.
For ethyl phenyl ketone (4k), methyl (4-trifluoromethyl)
benzyl ketone (4l) and methyl hexyl ketone (4m), the
yields of the related alcohols are between 78% and 85%.
We also studied the effect of catalyst on the
chemoselectivity of the system (Scheme 3). When
1 mmol of benzaldehyde and 1 mmol of acetophenone
were used as substrates in the presence of 1.1 mmol
silane, the conversion of aldehyde was much higher than
that of ketone (Scheme 3a). When 2.2 mmol silane were
added, almost equivalent conversion of aldehyde and
ketone could be achieved (Scheme 3b). Interestingly,
when α, β-unsaturated aldehyde (3-[4-chlorophenyl]
acrylaldehyde) and benzaldehyde (Scheme 3c) or
acetophenone (Scheme 3d) were used as substrates,
the conversion of α, β-unsaturated substrate is much
higher than that of aldehydes or ketones. Therefore, the
order of substrate activity for this catalytic system is
as follows: α, β-unsaturated aldehyde ꢂ benzaldehyde >
acetophenone.
1 is an effective catalyst for hydrosilylation of aldehydes
and ketones. Interestingly, the experimental results
showed that both ketones and aldehydes could be
reduced in good to excellent yields under the same cata-
lytic conditions. Chemoselective hydrosilylation reactions
indicate that the order of substrate activity for this
catalytic system is as follows: α, β - unsaturated
aldehyde ꢂ benzaldehyde > acetophenone under the
same conditions. Based on the experiments and literature
reports, a possible catalytic mechanism was proposed.
4 | EXPERIMENTAL SECTION
4.1 | General procedures and materials
All experiments and manipulations were carried out
under nitrogen atmosphere using standard Schlenk tech-
niques, unless otherwise noted. All solvents were dried
by general methods and freshly distilled before use.
Chlorosilylene,[23] PhC (NtBu)2SiOtBu,[17] Fe (PMe3)4
[24]
was prepared according to the reported procedures. All
the aldehydes, ketones and α, β-unsaturated carbonyl
compounds were purchased and used without further
purification. The purity of the triethoxysialne used is
95%, the other 5% is tetraethoxysialne. The silanes were
purchased from J&K scientific. Infrared spectra (4000–
400 cmꢀ1) were recorded on a Bruker ALPHA FT-IR
2.3 | Study on the catalytic reaction
mechanism
1
In order to understand the reaction mechanism, the stoi-
chiometric reaction of catalyst 1 with 2-acetonaphthone
or (EtO)3SiH was explored. The disappearance of Fe-H
signal in the in situ IR indicated that both reactions took
place, and the color of the reaction solution changed
from red to green or yellow. Unfortunately, we cannot
separate the products that can be characterized. These
two experiments imply that the intermediates containing
Fe-O or Fe-Si bond may be formed. Theoretical calcula-
tions show that the insertion of C=O bond into the M-H
bond is preferred over that into the M-Si bond.[21] Based
on the experiments and literature reports,[22] we propose
a possible catalytic mechanism (Scheme 4). The first step
from 1 to intermediate A is the ligand replacement. The
insertion of C=O bond into the Fe-H bond affords inter-
mediate B. After σ-bond metathesis via C the final prod-
uct (EtO)3Si-O-CRHR0 is formed with the recovery of
catalyst 1.
instrument by using Nujol mulls between KBr disks. H,
13C {1H}, 31P {1H} and 29Si {1H} NMR spectra were
recorded on Bruker Avance 300- and 400-MHz spectrom-
eters. Gas chromatography was performed by using a Fuli
9790 instrument with n-dodecane as an internal stan-
dard. Melting point was measured in capillarie sealed
under N2 and was uncorrected. Elemental analyses were
carried out on an Elementar Vario ELIII instrument.
4.2 | Synthesis of 1
A solution of ligand L1 (1.20 g, 3.61 mmol) in 30 ml of
THF was slowly added to a solution of Fe (PMe3)4
(1.30 g, 3.61 mmol) in 30 ml of THF at ꢀ78ꢁC, forming a
red reaction mixture. The reaction mixture was stirred
overnight. All volatiles were removed in vacuo. The
residue was extracted with 70-ml n-pentane. The
combined organic solutions were concentrated to 40 mL
and red crystals were formed at ꢀ20ꢁC. Yield: 1.55 g,
70%. Dec: >157 ꢁC Anal. calcd for C28H59FeN2OP3Si
(616.65 g/mol): C, 54.54; H, 9.64; N, 4.54. Found: C,
54.79; H, 9.50; N, 4.67. IR (Nujol mull, KBr, cmꢀ1): 1860
ν (Fe-H), 930 ρ (PCH3). 1H NMR (300 MHz, C6D6, 298 K,
ppm): ꢀ15.96 (dddd, 2JP,H = 15 Hz, 2JP,H = 30 Hz,
3 | CONCLUSION
In this paper, a novel silylene chelate iron hydride 1 was
synthesized by Csp3-H bond activation using zero-valent
iron complex Fe (PMe3)4. It has been found that complex

DU ET AL.
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2JP,H = 36 Hz, 1H, Fe-H), 0.90–2.08 (m, 53H, C [CH3]3),
PCH3, CH3, CH2) 7.24–7.95 (m, 5 H, Ar-H). 31P NMR
(121 MHz, C6D6, 298 K, ppm): 19.2–19.6 (m, 1P), 21.2–
21.8 (m, 2P). 13C NMR (75 MHz, C6D6, 298 K, ppm): 24.7
CONFLICT OF INTEREST
There are no conflicts to declare.
2
(m), 29.0 (m), 29.9, 32.0 (d, JP,c = 8 Hz), 33.2, 35.8, 53.4,
REFERENCES
54.5, 77.7 (Fe-CH2), 129.0 (Carom), 129.7 (Carom), 134.0
(Carom), 171.3 (NCN). 29Si NMR (59.59 MHz, C6D6,
298 K, ppm): 53.3 (m).
[1] a) S. Raoufmoghaddam, Y. P. Zhou, Y. Wang, M. Driess,
J. Organomet. Chem. 2017, 829, 2; b) Y. P. Zhou, M. Driess,
Angew. Chem., Int. Ed. 2019, 58, 3715; c) C. K. Shan, S. L. Yao,
M. Driess, Chem. Soc. Rev. 2020, 49, 6733.
[2] a) A. Fürstner, H. Krause, C. W. Lehmann, Chem. Commun.
2001, 2372; b) G. Tan, S. Enthaler, S. Inoue, B. Blom, M.
Driess, Angew. Chem., Int. Ed. 2015, 54, 2214; c) H. Ren,
Y. P. Zhou, Y. Bai, C. Cui, M. Driess, Chem. – Eur. J. 2017,
23, 5663.
4.3 | Representative experimental
procedure for the hydrosilylation reactions
Under a nitrogen atmosphere, 1-mmol aldehyde or
ketone substrate was weighed into a 20 mL Schlenk tube
[3] S. Khoo, J. Cao, M. C. Yang, Y. L. Shan, M. D. Su, C. W. So,
Chem. – Eur. J. 2018, 24, 14329.
[4] a) R. Chinchilla, C. Najera, Chem. Rev. 2007, 107, 874; b) R.
Chinchilla, C. Najera, Chem. Soc. Rev. 2011, 40, 5084.
[5] M. Stoelzel, C. Prasang, B. Blom, M. Driess, Aust. J. Chem.
2013, 66, 1163.
[6] M. P. Luecke, D. Porwal, A. Kostenko, Y. P. Zhou, S. Yao, M.
Keck, C. Limberg, M. Oestreich, M. Driess, Dalton Trans.
2017, 46, 16412.
[7] Y. Wang, A. Kostenko, S. Yao, M. Driess, J. Am. Chem. Soc.
2017, 139, 13499.
[8] A. Bruck, D. Gallego, W. Wang, E. Irran, M. Driess, J. F.
Hartwig, Angew. Chem., Int. Ed. 2012, 51, 11478.
[9] B. Blom, S. Enthaler, S. Inoue, E. Irran, M. Driess, J. Am.
Chem. Soc. 2013, 135, 6703.
[10] Z. Zuo, L. Zhang, X. Leng, Z. Huang, Chem. Commun. 2015,
51, 5073.
[11] Y. Bai, J. Zhang, C. Cui, Chem. Commun. 2018, 54, 8124.
[12] a) S. L. Zhou, D. Addis, S. Das, K. Junge, M. Beller, Chem.
Commun. 2009, 4883; b) R. Langer, G. Leitus, Y. Ben-David,
D. Milstein, Angew. Chem., Int. Ed. 2011, 50, 2120; c) I. Buslov,
J. Becouse, S. Mazza, M. Montandon-Clerc, X. L. Hu, Angew.
Chem., Int. Ed. 2015, 54, 14523; d) P. Kang, C. Cheng, Z. Chen,
C. K. Schauer, T. J. Meyer, M. Brookhart, J. Am. Chem. Soc.
2012, 134, 5500.
containing
a
magnetic stirring. Later, 1.2-mmol
(EtO)3SiH and 2 mmol% iron hydride 1 were added to
the tube. The system was then heated at 60ꢁC for 8 hr.
The conversion was determined by GC with n-dodecane
as an internal standard. After cooling to room tempera-
ture, the mixture was quenched with MeOH (2 ml) and a
10% aqueous solution of NaOH (2 ml) under vigorous
stirring at 60ꢁC for about 24 hr. The product alcohol was
extracted with 60-ml diethyl ether three times and dried
over Na2SO4. After filtration, the volatile materials were
evaporated in vacuo. The crude product was purified by
column chromatography over silica gel with a mixture of
petroleum ether and ethyl acetate (10:1) as the eluent to
yield the product. The pure product was characterized by
NMR analysis.
4.4 | X-ray structure determinations
Intensity data were collected on a Stoe Stadi Vari dif-
fractometer equipped with graphite-monochromatized
Ga Kα radiation (λ = 1.34143 Å). Crystallographic data
for complex 1 are summarized in the Supporting Infor-
mation. The structure was solved by direct methods
with the OLEX 2 program[25] and refined with full-
matrix least squares on all F2 (SHELXL).[26] All non-
hydrogen atoms were refined anisotropically. CCDC
1865448 (1) contains supplementary crystallographic
data for this paper.
[13] R. Imayoshi, K. Nakajima, J. Takaya, N. Iwasawa, Y.
Nishibayashi, Eur. J. Inorg. Chem. 2017, 3769.
[14] a) S. Wu, X. Li, Z. Xiong, W. Wu, Y. Lu, H. Sun, Organometal-
lics 2013, 32, 3227; b) S. Ren, S. Xie, T. Zheng, Y. Wang, S. Xu,
B. Xue, X. Li, H. Sun, O. Fuhrd, D. Fenske, Dalton Trans.
2018, 47, 4352.
[15] X. Qi, T. Zheng, J. Zhou, Y. Dong, X. Zuo, X. Li, H. Sun, O.
Fuhr, D. Fenske, Organometallics 2019, 38, 268.
[16] S. Li, Y. Wang, W. Yang, K. Li, H. Sun, X. Li, O. Fuhr, D.
Fenske, Organometallics 2020, 39, 757.
[17] R. Azhakar, R. S. Ghadwal, H. W. Roesky, H. Wolf, D. Stalke,
Organometallics 2012, 31, 4588.
[18] P. Bhattacharya, J. A. Krause, H. Guan, Organometallics 2011,
30, 4720.
[19] H. Tobita, A. Matsuda, H. Hashimoto, K. Ueno, H. Ogino,
Angew. Chem., Int. Ed. 2004, 43, 221.
ACKNOWLEDGMENTS
We gratefully acknowledge the support by the Natural
Science Foundation of Shandong Province ZR2019ZD46/
ZR2019MB065 and NSF China (no. 21971151/21572119).
[20] D. Gallego, S. Inoue, B. Blom, M. Driess, Organometallics
2014, 33, 6885.
[21] L. Zhao, N. Nakatani, Y. Sunada, H. Nagashima, J. Hasegawa,
J. Org. Chem. 2019, 84, 8552.
DATA AVAILABILITY STATEMENT
The data that supports the findings of this study are avail-
able in the supporting information of this article.

10 of 10
DU ET AL.
[22] a) A. Raya-Baron, P. Ona-Burgos, I. Fernandez, ACS Catal.
2019, 9, 5400; b) T. Bleith, H. Wadepohl, L. H. Gade, J. Am.
Chem. Soc. 2015, 137, 2456; c) Q. Niu, H. Sun, X. Li, H.-F.
Klein, U. Floerke, Organometallics 2013, 32, 5235.
[23] S. S. Sen, H. W. Roesky, D. Stern, J. Henn, D. Stalke, J. Am.
Chem. Soc. 2010, 132, 1123.
SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of this
article.
[24] H. H. Karsch, Chem. Ber. 1977, 110, 2699.
How to cite this article: X. Du, X. Qi, K. Li, X. Li,
H. Sun, O. Fuhr, D. Fenske, Appl Organomet Chem
2021, e6286. https://doi.org/10.1002/aoc.6286
[25] O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard,
H. Puschmann, J. Appl. Crystallogr. 2009, 42, 339.
[26] G. M. Sheldrick, Acta Crystallogr., Sect. A: Found. Crystallogr.
2008, 64, 112.