A Masked Cuprous Hydride as a Catalyst for Carbonyl Hydrosilylation in Aqueous Solutions

Article abstract of DOI:10.1002/anie.201811890

Redox-unstable cuprous hydridotriphenylborate was isolated as an N-heterocyclic carbene adduct [(IPr)Cu(HBPh₃)] (IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) with good thermal stability. Although this compound displays a contact ion-pa

Full text of DOI:10.1002/anie.201811890

A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
Chemie
International Edition
www.angewandte.org
Accepted Article
Title: A Masked Cuprous Hydride as a Catalyst for Carbonyl
Hydrosilylation in Aqueous Solutions
Authors: Jun Okuda, Thomas Spaniol, Alexander Hoffmann, Florian
Ritter, and Debabrata Mukherjee
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201811890
Angew. Chem. 10.1002/ange.201811890
Link to VoR: http://dx.doi.org/10.1002/anie.201811890
http://dx.doi.org/10.1002/ange.201811890

10.1002/anie.201811890
Angewandte Chemie International Edition
COMMUNICATION
A Masked Cuprous Hydride as a Catalyst for Carbonyl
Hydrosilylation in Aqueous Solutions
Florian Ritter, Debabrata Mukherjee, Thomas P. Spaniol, Alexander Hoffmann and Jun Okuda*
Abstract: Redox-unstable cuprous hydridotriphenylborate was
isolated as an N-heterocyclic carbene adduct [(IPr)Cu(HBPh3)] (IPr =
1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) with good thermal
stability. Despite a contact ion-pair structure, a Cu(I)H-like catalytic
activity was envisaged in carbonyl hydrosilylation. Sufficient moisture
stability allowed the catalysis in aqueous/organic media. Mechanistic
study further showed a phenyl group abstraction by [(IPr)Cu]+ from a
borate anion to give a cationic organocopper complex [(IPr)2Cu2(-
Ph)][BPh4].
complexes of electropositive metals (Li, Na, K, Mg, Zn, Al) as
chemoselective hydroboration catalysts for various polar
substrates including CO2.[6] Cu+ has the same size as Li+ [(rionic
=
0.6 Å (Cu+ for CN 4), 0.59 Å (Li+ for CN 4)] but is more
electronegative [Pauling = 1.90 (Cu), 0.98 (Li)] and softer.[7] Given
the stability difference between A and B and the increasing
order of hydridicity ([HB(C6F5)3]< [HBPh3] < [HBEt3]),[8] an
NHC-bonded ”Cu(HBPh3)“ may be compelling for further
exploitation. Here we describe the synthesis, structure, and
catalytic carbonyl hydrosilylation activity of an NHC-bonded
“Cu(HBPh3)” species.
Molecular cuprous hydrides are important as mild and
selective reducing agents, as intermediates in hydrofunctionaliz-
ation, and in many other catalytic reactions.[1] They are difficult
to isolate as a monomer due to the inherent redox-instability and
pronounced aggregation tendency.[1f] Phosphines[2] and N-
heterocyclic carbenes (NHCs)[3] are known to stabilize cuprous
hydrides of lower nuclearity, but a monomeric ”Cu(I)H” species
has only been detected spectroscopically in solution.[4]
Salt metathesis of [(IPr)CuI][9] (IPr
=
1,3-bis(2,6-
diisopropylphenyl)imidazol-2-ylidene)[10] with K(HBPh3)[6a] in Et2O
gave the NHC-bonded cuprous hydridotriphenylborate
[(IPr)Cu(HBPh3)] (1) in 57% yield (Scheme 1). 1 can be purified
by recrystallization (see SI). Use of THF instead of Et2O resulted
in an unwanted side product [(IPr)2Cu][BPh4] (2) via carbene and
phenyl ligand exchange (see below). 2 was independently
synthesized from [(IPr)CuI] with [(IPr)H•BPh4] and fully
characterized including a crystal structure analysis (see SI).
Whereas A or B were prepared by treating [(6Mes)CuOtBu] with
LiHBEt3 or with PhMe2SiH in the presence of B(C6F5)3,
respectively,[5] compound 1 was not accessible via any of these
methods. The synthesis of B using Et3SiH instead of PhMe2SiH
gave the by-product [(6Mes)2Cu][B(C6F5)4] that has a similar
composition as 2.[5]
Recently Whittlesey et al. reported cuprous hydridoborates
such as [(6Mes)Cu(HBR3)] [6Mes = 1,3-dimesitylhexahydro-
pyrimidine-2-ylidene; R = Et (A), C6F5 (B)], which may be
regarded as surrogates for monomeric ”Cu(I)H” (Fig. 1).[5]
However, A is stable only below 30 °C, while B persists for ca.
12 h at room temperature. Computational studies identified them
as contact ion-pairs consisting of [(6Mes)Cu]+ and [HBR3] rather
than as a borane adduct of monomeric cuprous hydrides
[(6Mes)CuH•BR3], despite the presence of Cu···H interactions.
Scheme 1: Synthesis of 1 by salt metathesis of IPrCuI with [K(HBPh3)].
Figure 1: NHC-bonded Cu(HBR3); R = Et, B(C6F5)3.[5]
Dimeric NHC- and CAAC (cyclic amino alkyl carbene)-
bonded cuprous hydrides are intensely colored (yellow to
orange).[4, 11] 1 is colorless like A and B, soluble in aromatic
hydrocarbons and stable for at least two days at 25 °C, or for
several hours at 40 ˚C. It decomposes immediately at 60 ˚C.
Dissolving 1 in THF or acetonitrile led to a complex mixture of 1,
2, and other minor species. An ancillary ligand-free “Cu(HBPh3)”
would be redox-unstable and decompose into Cu(0), BPh3 and
H2, rendering this compound inaccessible like [Zn(HBPh3)2].[6d]
Strong -donation and appropriate steric protection from IPr is
Recently, we established hydridotriphenylborate [HBPh3]
F. Ritter, Dr. D. Mukherjee,a Dr. T. P. Spaniol, Dr. A. Hoffmann, Prof.
Dr. J. Okuda*
Institute of Inorganic Chemistry, RWTH Aachen University
Landoltweg 1, 52056, Aachen (Germany)
E-mail: jun.okuda@ac.rwth-aachen.de
Homepage: http://www.ac.rwth-aachen.de/extern/ak-okuda
aNew address: Department of Chemistry, Indian Institute of
Technology Kharagpur, Kharagpur, West Bengal, 721302, India
Supporting information for this article is given via a link at the end of
the document.
This article is protected by copyright. All rights reserved.

10.1002/anie.201811890
Angewandte Chemie International Edition
COMMUNICATION
critical for kinetic stabilization, since the corresponding
between the Cu and H atoms but the interaction is weaker than
the BH bond. Second-order perturbation theory as
implemented in NBO 6.0 gave four donor-acceptor interactions
around copper. The Cipso-Cu interaction is stabilized by 18.3
kcal/mol, the CcarbeneCu donation amounts to 80.4 kcal/mol,
and the B-H Cu donation to 26.3 kcal/mol. Additionally, the
B-Cipso bond donates toCu by 9.9 kcal/mol. Comparing the
NBO and the QTAIM charges of the whole complex with two
hypothetical fragment pairs [(carbene)Cu]+[HBPh3] or
[(carbene)CuH] and [BPh3] agreed better with the hydridoborate
formulation.
[(IMes)Cu(HBPh3)] (IMes
=
1,3-bis(2,4,6-trimethylphenyl)-
imidazol-2-ylidene) was not isolable.
The crystal structure determined by X-ray diffraction shows
the monomeric contact ion pair structure for 1, similar to that of
A and of B.[5] The anion [HBPh3] is bonded to [(IPr)Cu]+ through
the Cu···HB interaction and an additional Cu···Cipso
coordination from one of the three phenyl rings. The hydride
position was located from a Fourier difference map and was
refined. The Cu∙∙∙H distance of 1.59(3) Å is similar to 1.55(3) Å
in both A and B, but the CuCipso contact of 2.166(2) Å is slightly
shorter than 2.2183(17) Å found in B. The ∠IPrCuH angle of
136.1(11)° is more acute than 162.8(14)° and 146.5(8)° in A and
B, respectively.
The fair stability of 1 prompted us to test its activity in
[1d]
carbonyl hydrosilylation catalysis.
The reduction of carbonyl
groups with PhMeSiH2 was catalyzed by 0.1-1.0 mol% of 1
under mild conditions in both benzene and THF (Table 1).
Polymethylhydrosiloxane (PMHS) as reductant gave lower
conversions. Aldehydes were expectedly easier to reduce and
required less catalyst than ketones. Various para-substituted
benzaldehydes containing electron donating and withdrawing
groups (Table 1, entry 1) as well as furfural (Table 1, entry 2)
were hydrosilylated with equal efficiency. The aliphatic
cyclohexanone and dicyclohexylketone (Table 1, entry 3 and 4)
were more reactive than acetophenone or benzophenone (Table
1, entry 5 and 6). The cinnamaldehyde and 2-cyclohexen-1-one
were hydrosilylated in 1,2-fashion with 97% regioselectivity
(Table 1, entry 7 and 8). The current system shows a better
activity for carbonyl hydrosilylation when compared to other
“NHC-Cu” catalysts reported in the literature.[13]
Table 1: Carbonyl hydrosilylation catalyzed by 1 using PhMeSiH2.[a]
Figure 2: Molecular structure of 1. Displacement parameters are set at 50%
probability level; solvent molecules and hydrogen atoms except of H1 are
omitted for clarity. Selected bond distances [Å] and angles [°]: Cu1C1
1.888(3), Cu1H1 1.59(3), B1H1 1.17(3), Cu1C28 2.166(2), ∠C1Cu1H1
136.1(11).
The 1H NMR spectrum of 1 in [D6]benzene shows the
Cat.
mol%
%
Time
(h)
Entry
1[c]
Substrate
Product
Conv.[b]
characteristic resonances of a coordinated IPr carbene and a
1
[HBPh3] anion, but unlike the alkali metal salts, the JBH
coupling is not apparent due to the broad HB ( = 3.42 ppm).
0.1
0.1
0.1
>95
>95
>95
<0.2
<0.2
4
1
Signals for BH ( = 10.5 ppm) in the H and 11B NMR spectra,
were not resolved even at 60 °C. This suggests that a
significant Cu···HB interaction is maintained in solution. This
may also explain the solubility difference between 1 and the
alkali metal salts which are not soluble in aromatic hydrocarbons.
The HB resonances of A ( = 2.60 ppm at 64 °C) and B ( =
2.08 ppm) are quite different.[5] The solid state IR (KBr) spectrum
shows a broad absorption at BH = 1693 cm1.
2
3
The extent of Cu···H···B interaction in 1 was probed by
DFT calculations on the basis of the NBO analysis, the Wiberg
bond indices and of the quantum theory of atoms in molecules
(QTAIM) analysis.[12] The Wiberg bond indices (as implemented
in Gaussian 09) show a high covalency of the BH bond. The
QTAIM analysis (see SI) detects an additional bond critical point
4
1.0
>95
<0.2
This article is protected by copyright. All rights reserved.

10.1002/anie.201811890
Angewandte Chemie International Edition
COMMUNICATION
5
6
1.0
1.0
0.1
>95
>95
>95
16.5
44
Entry
1
Substrate
Product
% Conv.[b]
>95
Time (h)
19
7[d]
0.7
8[d]
1.0
>95
<0.2
2
3
78
58
24
26
(a) n(PhMeSiH2)
= 0.18 mmol, n(substrate) = 0.18 mmol, 0.5 mL of
[D6]benzene. (b) % Conversion determined by 1H NMR spectroscopy using
hexamethylbenzene (0.03 mM) as an internal standard. (c) X = H, Br, F, OMe,
NO2, Me, CN. (d) Trace amounts of C=C double bond reduction.
Complex 1 is surprisingly robust against moisture. A
[D8]THF solution containing 10% (v/v) of water remained visibly
and spectroscopically unchanged at room temperature for at
least 6 h. Standing for 24 h led to only ca. 10% decomposition.
Catalysis in aqueous or aqueous/organic media by NHC-
supported transition metal complexes including copper is of
current interest.[14] Due to the poor solubility of 1, the substrates,
and tetramethyldisiloxane (Me2SiH)2O in neat water, a H2O/THF
(1:4) mixture was used as solvent. As summarized in Table 2,
the reaction time is significantly longer, likely due to
inhomogeneity of the system. 1 can be generated in situ for
catalysis by mixing [(IPr)CuI] and KHBPh3 under N2, followed by
adding the THF/H2O solvent mixture and a mixture of substrate
and hydrosilane. However, a bench-top experiment run in open
air did not lead to conversion.
4
5
>95
74
19
26
(a) n((Me2SiH)2O) = 0.18 mmol, n(substrate) = 0.18 mmol, 0.2 mL of D2O and
0.8 mL of THF (1:4). (b) % Conversion determined by 1H NMR spectroscopy
using hexamethylbenzene (0.03 mM) as an internal standard.
Complex 1 also catalyzed the carbonyl hydroboration with
pinacolborane (HBpin). Similar to the alkali metal salts,[6a] 1 did
not react with polar and nonpolar functional groups such as
imine, amide, ester, nitrile, olefin, and internal alkyne under
stoichiometric as well as catalytic conditions. Reaction with
pyridine led to decomposition.
Air- and moisture-sensitivity of cuprous hydrides vary with
nuclearity and ligand encapsulation. Polymeric [CuH]ꚙ is
produced in water, but dry [CuH]ꚙ is pyrophoric.[15] The
hexameric Stryker’s reagent [(PPh3)CuH]6 is also air-sensitive,
but water-stable.[2] Dimeric cuprous hydrides are thermally
Reaction between
1 and PhC(O)R (R = H, Ph) in
benzene/[D6]benzene unexpectedly precipitated an ionic
complex identified as [(IPr)2Cu2(-Ph)][BPh4] (3) in 70% yield
(Scheme 3). The same outcome was obtained using THF or
Et2O, except that 3 remained soluble. Monitoring the reactions in
[D6]benzene by 1H NMR spectroscopy revealed fast carbonyl
insertion to give [(IPr)Cu][Ph3BOR‘] (R‘ = CHPhR), followed by
phenyl and alkoxy group migrations to ultimately precipitate 3
(Scheme 3). The actual scrambling process is complicated as
signals of several other boranes and borates were detected by
11B NMR spectroscopy. Intriguingly, 1 is stable toward such
exchange process in benzene or Et2O, but the more polar
solvents like THF or acetonitrile trigger the formation of 2.
11, 16]
unstable as well as against air and moisture.[4,
Some
chalcogen-stabilized polyhydrido copper clusters over a wide
range of nuclearities (Cu7 to Cu32) on the other hand exhibit
exceptional air and moisture stability.[17] Catalytically active
cuprous hydrides including those supported by NHCs are often
generated in situ during hydrosilylation.[1c, 1h, 3b, 3c] Protic reagents
such as t-BuOH are used on many such instances to enhance
reaction rates without impeding the catalyst’s activity.[1c, 1h, 3b, 3c]
The sensitivity of A and B against air and moisture were not
reported, but both compounds are thermally less stable than 1.[5]
Table 2: Carbonyl hydrosilylation catalyzed by 1 in a 4:1 water/THF mixture.
This article is protected by copyright. All rights reserved.

10.1002/anie.201811890
Angewandte Chemie International Edition
COMMUNICATION
Scheme 2: Formation of 3 via phenyl abstraction by [(IPr)Cu]+.
Organocopper(I) chemistry is dominated by cuprates
[CuR2] and neutral clusters [CuR]n,[18] whereas cationic
complexes with bridging aryl groups are rare. Apart from 3, few
other examples include [Cu3Ph2(pmdta)2][Cu5Ph6] (PMDTA =
N,N,N’,N”,N”-pentamethyldiethylenetriamine)[19] and [Cu2(μ-
η1:η1-Ar)(DPFN)]X (Ar = C6H5, 3,5-(CF3)2-C6H3, and C6F5; DPFN
Figure 3: Molecular structure of 3. Displacement parameters are set at 50%
probability level; solvent molecules, hydrogen atoms and the [BPh4] anion are
omitted for clarity. Selected bond distances [Å] and angles [°]: Cu1-C1
1.908(2), Cu1-Cu2 2.5373(4), Cu1-C55 1.964(2), Cu2-C55 1.962(2), C1-Cu1-
C55 154.32(9), C28-Cu2-C55 156.89(8).

= 2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine; X = BAr4

and NTf2 ; Tf = SO2CF3).[20] These DPFN complexes were
obtained in a similar manner from the dicationic [Cu2(μ-η1:η1-


NCCH3)(DPFN)]X2 (X
= PF6 and NTf2 ) by aryl group
The reaction between 1 and PhCHO (1:1) with an excess of
PhMeSiH2 in [D6]benzene gave only PhMeSiHOCH2Ph and
regenerated 1. Conversely, the reaction of 1 and PhMeSiH2 (1:1)
with an excess of PhCHO gave the silyl ether and 3. Thus, the
formation of 3 depends on the reaction stoichiometry and is not
operative under catalytic condition as long as hydrosilane is
present. Complex 3 is a much poorer catalyst than 1 for carbonyl
hydrosilylation (see SI). Free BPh3 is also incapable of
hydrosilylation catalysis under this condition.[24]
abstraction from [BAr4] anions. This was explained by the
constrained geometry of the [Cu2(DPEN)]2+ motif and the
cooperative electrophilic effect exhibited by the two Cu+ centers
in close proximity. Aryl group transfer from boron to copper
centers is also common in copper mediated CC coupling
reactions.[21] The same carbene IPr stabilizes a -hydrido

dicopper cation as [(IPr)2Cu2(-H)][A] (A = BF4 , OTf).[22]
Interestingly, the cationic -aryls react with acidic alkynes under
protonation to give cationic -alkynyl dicopper complexes,[23]
while the -hydride reacts with the alkynes under insertion to
give -vinyl derivatives.[22b]
In conclusion, the redox-unstable ”Cu(HBPh3)“ has been
stabilized by the N-heterocyclic carbene IPr as a contact ion-pair
1, whose thermal and moisture stability is notable. It shows
catalytic carbonyl hydrosilylation activity in aqueous media.
Formation of the cationic cuprous aryl complex 3 by phenyl
abstraction highlights the electrophilicity of Cu+, despite being
coordinated to the strong -donor IPr.
The solid-state structure of 3 exhibits two IPr-bonded copper
centers with three-coordinate geometry, bridged symmetrically
by a phenyl ligand [Cu1−C55: 1.964(2) Å; Cu2−C55: 1.962(2)
Å]; the phenyl moiety shows no preferential inclination toward
either copper center. The Cu···Cu distance of 2.5373(4) Å is
longer than 2.3927(5) Å in [Cu2(μ-η1:η1-Ph)(DPFN)][BPh4].[20b]
1
The H NMR spectrum of 3 in [D8]THF shows the characteristic
resonances of a coordinated IPr and [BPh4] anion in 2:1 ratio.
Signals of the bridging phenyl group appeared broad, likely due
to free rotation across the Cu∙∙∙Cu motif which was not the case
for [Cu2(μ-η1:η1-Ph)(DPFN)]BPh4 due to its rigid geometry.[20b]
Acknowledgement
We thank the Deutsche Forschungsgemeinschaft for financial
support through the International Research Training Group
“Selectivity in Chemo- and Biocatalysis”, the Alexander von
Humboldt Foundation for a fellowship to D.M. and the Regional
Computing Center of the University of Cologne (RRZK) for
providing computing time on the DFG-funded High Performance
Computing (HPC) system CHEOPS and the Paderborn Cluster
for Parallel Computing (PC2 Paderborn).
Keywords: Copper
•
Hydridotriphenylborate
•
Carbonyl reduction
•
Hydrosilylation • Catalysis in water
This article is protected by copyright. All rights reserved.

10.1002/anie.201811890
Angewandte Chemie International Edition
COMMUNICATION
[1]
a) A. J. Jordan, G. Lalic, J. P. Sadighi, Chem. Rev. 2016, 116, 8318-
8372; b) Y. Tsuji, T. Fujihara, Chem. Rec. 2016, 16, 2294-2313; c) C.
Deutsch, N. Krause, B. H. Lipshutz, Chem. Rev. 2008, 108, 2916-2927;
d) S. Díez-González, S. P. Nolan, Org. Prep. Proced. Int. 2007, 39,
523-559; e) S. Díez-González, S. P. Nolan, Acc. Chem. Res. 2008, 41,
349-358; f) A. P. Humphries, H. D. Kaesz, in Progress in Inorganic
Chemistry, John Wiley & Sons, 2007, pp. 145-222; g) M. T. Pirnot, Y.-M.
Wang, S. L. Buchwald, Angew. Chem. Int. Ed. 2016, 55, 48-57; h) V.
Jurkauskas, J. P. Sadighi, S. L. Buchwald, Org. Lett. 2003, 5, 2417-
2420.
Bohmann, C. M. Morales, C. R. Landis, F. Weinhold, NBO 6.0,
Theoretical Chemistry Institute, University of Wisconsin, Madison, 2013.
[13] a) S. Díez-González, H. Kaur, F. K. Zinn, E. D. Stevens, S. P. Nolan, J.
Org. Chem. 2005, 70, 4784-4796; b) S. Díez-González, N. M. Scott, S.
P. Nolan, Organometallics 2006, 25, 2355-2358; c) S. Díez-González,
E. D. Stevens, N. M. Scott, J. L. Petersen, S. P. Nolan, Chem. Eur. J.
2008, 14, 158-168; d) S. Díez-González, E. C. Escudero-Adán, J.
Benet-Buchholz, E. D. Stevens, A. M. Z. Slawin, S. P. Nolan, Dalton
Trans. 2010, 39, 7595-7606; e) M. Teci, N. Lentz, E. Brenner, D. Matt,
L. Toupet, Dalton Trans. 2015, 44, 13991-13998; f) T. Vergote, F.
Nahra, D. Peeters, O. Riant, T. Leyssens, J. Org. Chem. 2013, 730, 95-
103; g) T. Vergote, F. Nahra, A. Welle, M. Luhmer, J. Wouters, N.
Mager, O. Riant, T. Leyssens, Chem. Eur. J. 2012, 18, 793-798; h) J.
Yun, D. Kim, H. Yun, Chem. Commun. 2005, 5181-5183.
[2]
[3]
a) S. A. Bezman, M. R. Churchill, J. A. Osborn, J. Wormald, J. Am.
Chem. Soc. 1971, 93, 2063-2065; b) W. S. Mahoney, D. M. Brestensky,
J. M. Stryker, J. Am. Chem. Soc. 1988, 110, 291-293.
a) S. Gaillard, C. S. J. Cazin, S. P. Nolan, Acc. Chem. Res. 2012, 45,
778-787; b) F. Lazreg, C. S. J. Cazin, in N-Heterocyclic Carbenes,
Wiley-VCH, 2014, pp. 199-242; c) F. Lazreg, F. Nahra, C. S. J. Cazin,
Coord. Chem. Rev. 2015, 293–294, 48-79; d) L. Zhang, Z. Hou, Chem.
Sci. 2013, 4, 3395-3403.
[14] a) H. D. Velazquez, F. Verpoort, Chem. Soc. Rev. 2012, 41, 7032-
7060; b) E. Levin, E. Ivry, C. E. Diesendruck, N. G. Lemcoff, Chem.
Rev. 2015, 115, 4607-4692; c) W. Wang, G. Zhang, R. Lang, C. Xia, F.
Li, Green Chem. 2013, 15, 635-640; d) V. B. Purohit, S. C. Karad, K. H.
Patel, D. K. Raval, RSC Adv. 2014, 4, 46002-46007; e) C. Sambiagio,
R. H. Munday, A. J. Blacker, S. P. Marsden, P. C. McGowan, RSC Adv.
2016, 6, 70025-70032; f) M. Pellei, V. Gandin, C. Marzano, M. Marinelli,
F. Del Bello, C. Santini, Appl. Organomet. Chem. 2018, 32, 4185.
[15] a) P. Hasin, Y. Wu, Chem. Commun. 2012, 48, 1302-1304; b) R.
Burtovyy, E. Utzig, M. Tkacz, Thermochim. Acta 2000, 363, 157-163; c)
N. P. Fitzsimons, W. Jones, P. J. Herley, J. Chem. Soc. Faraday Trans.
1995, 91, 713-718.
[4]
[5]
[6]
E. A. Romero, P. M. Olsen, R. Jazzar, M. Soleilhavoup, M. Gembicky,
G. Bertrand, Angew. Chem. Int. Ed. 2017, 56, 4024-4027.
L. R. Collins, N. A. Rajabi, S. A. Macgregor, M. F. Mahon, M. K.
Whittlesey, Angew. Chem. Int. Ed. 2016, 55, 15539-15543.
a) D. Mukherjee, H. Osseili, T. P. Spaniol, J. Okuda, J. Am. Chem. Soc.
2016, 138, 10790-10793; b) D. Mukherjee, S. Shirase, T. P. Spaniol, K.
Mashima, J. Okuda, Chem. Commun. 2016, 52, 13155-13158; c) D.
Mukherjee, H. Osseili, K.-N. Truong, T. P. Spaniol, J. Okuda, Chem.
Commun. 2017, 53, 3493-3496; d) D. Mukherjee, A.-K. Wiegand, T. P.
Spaniol, J. Okuda, Dalton Trans. 2017, 46, 6183-6186; e) H. Osseili, D.
Mukherjee, K. Beckerle, T. P. Spaniol, J. Okuda, Organometallics 2017,
36, 3029-3034; f) H. Osseili, D. Mukherjee, T. P. Spaniol, J. Okuda,
Chem. Eur. J. 2017, 23, 14292-14298.
[16] B. H. Lipshutz, B. A. Frieman, Angew. Chem. Int. Ed. 2005, 44, 6345-
6348.
[17] R. S. Dhayal, W. E. van Zyl, C. W. Liu, Acc. Chem. Res. 2016, 49, 86-
95.
[18] S. H. Bertz, G. Dabbagh, X. He, P. P. Power, J. Am. Chem. Soc. 1993,
115, 11640-11641.
[7]
P. J. Pérez, M. M. Díaz-Requejo, Comprehensive Organometallic
Chemistry III, Elsevier, Amsterdam, 2007, pp. 153-195.
[19] X. He, K. Ruhlandt-Senge, P. P. Power, S. H. Bertz, J. Am. Chem. Soc.
1994, 116, 6963-6964.
[8]
[9]
Z. M. Heiden, A. P. Lathem, Organometallics 2015, 34, 1818-1827.
S. A. Delp, L. A. Goj, M. J. Pouy, C. Munro-Leighton, J. P. Lee, T. B.
Gunnoe, T. R. Cundari, J. L. Petersen, Organometallics 2011, 30, 55-
57.
[20] a) T. C. Davenport, T. D. Tilley, Angew. Chem. Int. Ed. 2011, 50,
12205-12208; b) M. S. Ziegler, D. S. Levine, K. V. Lakshmi, T. D. Tilley,
J. Am. Chem. Soc. 2016, 138, 6484-6491.
[10] J. Huang, S. P. Nolan, J. Am. Chem. Soc. 1999, 121, 9889-9890.
[11] a) N. P. Mankad, D. S. Laitar, J. P. Sadighi, Organometallics 2004, 23,
3369-3371; b) G. D. Frey, B. Donnadieu, M. Soleilhavoup, G. Bertrand,
Chem. Asian J. 2011, 6, 402-405; c) A. J. Jordan, C. M. Wyss, J. Bacsa,
J. P. Sadighi, Organometallics 2016, 35, 613-616; d) C. M. Zall, J. C.
Linehan, A. M. Appel, J. Am. Chem. Soc. 2016, 138, 9968-9977.
[21] A. Verma, W. L. Santos, in Boron Reagents in Synthesis, Vol. 1236,
American Chemical Society, 2016, pp. 313-356.
[22] a) C. M. Wyss, B. K. Tate, J. Bacsa, T. G. Gray, J. P. Sadighi, Angew.
Chem. Int. Ed. 2013, 52, 12920-12923; b) A. M. Suess, M. R. Uehling,
W. Kaminsky, G. Lalic, J. AM. Chem. Soc. 2015, 137, 7747-7753.
[23] M. S. Ziegler, K. V. Lakshmi, T. D. Tilley, J. Am. Chem. Soc. 2017, 139,
5378-5386.
[12] a) E. D. Glendening, C. R. Landis, F. Weinhold, Valency and Bonding :
a
Natural Bond Orbital Donor-Acceptor Perspective, Cambridge
[24] D. Mukherjee, S. Shirase, K. Mashima, J. Okuda, Angew. Chem. Int.
Ed. 2016, 55, 13326-13329.
University Press, Cambridge, 2005; b) E. D. Glendening, C. R. Landis,
F. Weinhold, J. Comput. Chem. 2013, 34, 2134-2134; c) E. D.
Glendening, J. K. Badenhoop, A. E. Reed, J. E. Carpenter, J. A.
This article is protected by copyright. All rights reserved.

10.1002/anie.201811890
Angewandte Chemie International Edition
COMMUNICATION
Entry for the Table of Contents (Please choose one layout)
COMMUNICATION
Monomeric Cu(HBPh3)
supported by an N-
heterocyclic carbene
catalyzed the carbonyl
hydrosilylation in water
as a co-solvent.
Florian Ritter, Debabrata
Mukherjee, Thomas P.
Spaniol, Alexander
Hoffmann, Jun Okuda*
Page No. – Page No.
A Masked Cuprous
Hydride as a Catalyst
for Carbonyl
Hydrosilylation in
Aqueous Solutions
This article is protected by copyright. All rights reserved.