Gold-Catalyzed Direct C(sp3)?H Acetoxylation of Saturated Hydrocarbons

Article abstract of DOI:10.1002/cctc.202100804

In this communication we report our studies towards the development of a gold-catalyzed direct acetoxylation of C(sp³)?H bonds. We achieve this through the use of the hypervalent iodine reagent PhI(OAc)₂ in combination with a simple gold salt (HAuBr₄) as the catalyst. Through a comparison of the reactivities of cyclooctane and adamantane we judge the reaction to proceed via hydride transfer. This is further substantiated through computational studies of the relative energies for the anions, radicals and cations derived from C?H bond cleavage of cyclooctane and adamantane relevant to the C?H cleaving step.

Full text of DOI:10.1002/cctc.202100804

Communications
doi.org/10.1002/cctc.202100804
ChemCatChem
3
Gold-Catalyzed Direct C(sp )À H Acetoxylation of Saturated
Hydrocarbons
Tae Geun Jo and Johannes E. M. N. Klein*
[a]
[a]
3
[6]
In this communication we report our studies towards the
C(sp )À H bond oxidation reactions. Similarly, Shul’pin et al.
development of a gold-catalyzed direct acetoxylation of C-
reported that gold salts/complexes are capable of oxidizing
3
3
(
sp )À H bonds. We achieve this through the use of the hyper-
C(sp )À H bonds in simple hydrocarbons, such as cyclooctane,
valent iodine reagent PhI(OAc) in combination with a simple
using either H O or simply aerobic conditions as the terminal
2 2
2
[7]
gold salt (HAuBr ) as the catalyst. Through a comparison of the
oxidant (Scheme 1a). These reports indicate that gold is
capable of activating oxidants for the transformation of CÀ H
into CÀ O bonds and demonstrate the potential for gold to serve
as a catalyst for these types of transformations. In stoichiometric
experiments, it was also shown that gold(III) hydroxide com-
plexes can oxidize C(sp )À H bonds. Recently, two independent
reports by the groups of Wang and Michelet showed that
simple gold salts/complexes, when combined with PhI(OAc) ,
4
reactivities of cyclooctane and adamantane we judge the
reaction to proceed via hydride transfer. This is further
substantiated through computational studies of the relative
energies for the anions, radicals and cations derived from CÀ H
bond cleavage of cyclooctane and adamantane relevant to the
CÀ H cleaving step.
3
[8]
[9]
[10]
[
11]
2
2
are capable of acetoxylating C(sp )À H bonds in aromatic
compounds (Scheme 1b). In addition, very similar reaction
conditions were reported by Guo et al. for the acetoxylation of
The activation and more broadly formulated functionalization
of unreactive CÀ H bonds has in the past two decades become
an indispensable tool. As a consequence, the once considered
inert CÀ H bond has gradually been promoted to the status of a
3
[12]
C(sp )À H bonds of methyl sulfides. Notably this reaction has
been proposed to proceed via the initial formation of a
sulfonium salt without the involvement of the gold catalyst. In
the present article, we explore if the reaction conditions
reported for the acetoxylation of aromatic compounds are
[1]
functional group. In particular, the application of transition
[2]
metals as catalysts has impacted this area substantially. The
use of gold-based catalysts has admittedly taken a niche
existence and a rather narrow array of reactions has been
reported that predominantly center around the modification of
3
transferable to the reaction with C(sp )À H bonds of saturated
unactivated hydrocarbons, with the aim to develop a direct
acetoxylation reaction (Scheme 1c).
2
[3]
C(sp)À H and C(sp )À H bonds. In contrast, the functionalization
3
of C(sp )À H bonds has been reported less frequently due to the
comparatively lower reactivity. When these types of reactions
are reported, however, it is notable that this challenging step is
frequently embedded into complicated mechanistic pathways
[4]
with complex reaction sequences. An exception are reactions
that involve intramolecular hydride shifts, facilitated by gold as
[5]
catalysts, where several examples have been reported.
Interestingly, Periana and co-workers already reported in
004 that gold could catalyze the oxidation of methane to
2
methanol, which represents one of the most challenging
[
a] T. G. Jo, Dr. J. E. M. N. Klein
Molecular Inorganic Chemistry, Stratingh Institute for Chemistry
Faculty of Science and Engineering
University of Groningen
Nijenborgh 4, 9747 AG Groningen (The Netherlands)
E-mail: j.e.m.n.klein@rug.nl
Supporting information for this article is available on the WWW under
https://doi.org/10.1002/cctc.202100804
This publication is part of the Young Researchers Series. More information
regarding these excellent researchers can be found on the ChemCatChem
homepage.
©
2021 The Authors. ChemCatChem published by Wiley-VCH GmbH. This is
an open access article under the terms of the Creative Commons Attribution
Non-Commercial License, which permits use, distribution and reproduction
in any medium, provided the original work is properly cited and is not used
for commercial purposes.
Scheme 1. Gold-catalyzed CÀ H functionalization.
ChemCatChem 2021, 13, 1–6
1
© 2021 The Authors. ChemCatChem published by Wiley-VCH GmbH
��
These are not the final page numbers!

Communications
doi.org/10.1002/cctc.202100804
ChemCatChem
Our exploration began with simply applying reaction
observed an increase in yield, however, the observed TON
slightly decreased (Table 1, entries 9 and 10). Therefore, we
have used 2 mol% for all subsequent reactions. To probe if the
reaction benefitted from acid catalysis, which we introduced
with the choice of gold salt made, we used the potassium
congener KAuBr4 instead and observed essentially the same
catalytic activity (Table 1, entry 11). A side product we occasion-
ally observed in these transformations was acetoxylated
iodobenzene (see supporting information for details), which can
be ascribed to the decomposition of the oxidant. To probe if
the efficiency of the process could be increased by preventing
this decomposition, we tested two modifications of the oxidant,
conditions that mimicked those reported for the acetoxylation
of aromatic compounds (Table 1) using cyclooctane as a
À 1 [13]
substrate, with a reported BDE of 95.7 kcalmol . When we
carried the reaction out under an atmosphere of N2 using
simple Ph PAuCl or AuCl we observed an essentially stoichio-
3
3
metric formation of the acetoxylated product with respect to
the amount of gold added (Table 1, entries 1 and 2). In contrast,
when these reactions were performed under aerobic conditions
a slight increase for the acetoxylated product was observed
with concomitant formation of alcohol and ketone products
(
Table 1, entries 3 and 4). This raised the question if the alcohol
and ketone products were formed with the involvement of
being the penta-fluoro and p-NO versions (Table 1, entries 12
and 13). For the penta-fluoro substituted oxidant this resulted
in no significant improvement of the TONs for the acetoxylation
2
[7a]
gold, much as in the case of the report of Shul’pin et al., or if
there was a pathway that would not require any transition
metal catalyst. We found that in the absence of gold the
reaction. However, the use of the p-NO substituted oxidant did
2
[14]
reaction readily produces alcohol and ketone, yet does not
lead to noticeable amounts of acetoxylated product. When
oxygen was removed, this pathway leading to alcohol and
ketone is suppressed (Table 1, entries 5 and 6). Furthermore, no
oxygenated products were observed in the absence of gold and
the oxidant under aerobic reaction conditions (Table 1, entry 7).
increase the yield of acetoxylation slightly and provided a TON
of 8.
To develop a better idea of the nature of this reaction, we
decided to explore the oxidation of another substrate with a
comparable reported CÀ H BDE. We selected adamantane, which
À 1
features tertiary CÀ H bonds with a BDE of 96.2 kcalmol , in
This means that there is a PhI(OAc) -promoted pathway towards
addition to
a
set of secondary ones with a BDE of
2
À 1 [15]
alcohol and ketone formation, which is not affected by gold.
We assign the small amount of acetoxylated product, which
was also formed in the absence of oxygen, to originate from a
gold-promoted process and subsequently further evaluated
different gold sources (see supporting information for further
98.4 kcalmol . This choice of substrate allows us to examine
3
how the nature of the C(sp )À H bond influences reactivity and
also probes selectivity. When applying the reaction conditions
that resulted in catalytic turnover (HAuBr ) we also observed
4
acetoxylation (Table 2). This reaction showed the expected
preference for the weaker tertiary CÀ H bond. Most notably, the
TONs are higher, especially when considering the sum of
acetoxylated products. Unlike in the case of cyclooctane, the
amounts of alcohol and ketone formed are much lower.
However, when we carried the reaction out in the absence of
HAuBr4 under aerobic conditions we observed alcohol and
ketone products alongside a significant amount of acetoxylated
details). We found that a catalytic amount of HAuBr resulted in
4
an increased yield and resulted in TONs of 4.5–5. Noticeably,
this was not significantly influenced by the presence or absence
of air. In the presence of air, however, the background reaction,
producing alcohol and ketone side products, was again
observed. Throughout we have used a catalyst loading of
2
mol%. When we increased the catalyst loading to 5 mol% we
[a]
Table 1. Acetoxylation of cyclooctane.
[
b,c]
[b,c]
[b]
[b]
Entry
Catalyst
Oxidant
Aerobic / N
2
-one
%]
-ol
Yield of product
[%]
TON
[
[%]
1
2
3
4
5
6
7
8
9
1
1
1
1
Ph
AuCl
Ph PAuCl
3
PAuCl
3
X=H
X=H
X=H
X=H
X=H
X=H
–
5
5
5
5
5
5
N
N
2
n/o
n/o
11
8
12
trace
n/o
8
n/o
n/o
n/o
n/o
2
trace
1
trace
n/o
1
n/o
n/o
trace
trace
trace
2
2
5
5
n/o
n/o
n/o
8
10
16
9
1
1
2
2
–
–
–
4
5
3
5
5
8
2
3
Aerobic
Aerobic
Aerobic
AuCl
3
–
–
–
N
2
Aerobic
Aerobic
HAuBr
HAuBr
HAuBr
4
4
4
X=H
X=H
X=H
X=H
5
5
5
5
N
2
N
2
N
2
N
2
N
2
[
d]
0
1
2
3
KAuBr
HAuBr
HAuBr
4
trace
trace
trace
[
[
e]
e]
4
4
X= F
5
10
16
X=p-NO
2
[
a] Reaction conditions: substrate (2.5 mmol), oxidant (0.5 mmol), catalyst (2 mol%), DCE (1 mL), 110°C, 3 h. Yields lower than 1% are listed as trace. n/o=
Not observed. Experiments were performed in triplicate. [b] Yields and TONs were determined by GC using mesitylene as an internal standard; [c] Yields of
cyclooctanol and cyclooctanone; [d] catalyst (5 mol%); [e] Single run.
ChemCatChem 2021, 13, 1–6
www.chemcatchem.org
2
© 2021 The Authors. ChemCatChem published by Wiley-VCH GmbH
��
These are not the final page numbers!

Communications
doi.org/10.1002/cctc.202100804
ChemCatChem
[a]
Table 2. Acetoxylation of adamantane.
[
b,c]
[b,c]
[b]
[b]
[b,d]
Entry
Catalyst
Oxidant
Aerobic / N
2
-one
%]
-ol
Yield of 3° acetate
Yield of 2° acetate
TON
[
[%]
[%]
[%]
1
2
3
4
5
6
7
HAuBr
4
X=H
X=H
X=H
X=H
–
5
5
5
5
Aerobic
4
n/o
5
trace
n/o
n/o
n/o
trace
trace
8
n/o
11
trace
n/o
n/o
n/o
trace
trace
30
15
14
2
n/o
17
2
8
4
2
19
10
–
–
–
11
1
11
HAuBr
4
N
2
–
–
–
Aerobic
N
2
trace
n/o
6
trace
6
Aerobic
KAuBr
p-TsOH
4
X=H
X=H
5
N
2
N
2
N
2
N
2
5
[
e]
8
9
HAuBr
4
X=F
5
16
5
HAuBr
4
X=p-NO
2
1
3
[
a] Reaction conditions: substrate (2.5 mmol), oxidant (0.5 mmol), catalyst (2 mol%), DCE (1 mL), 110°C, 3 h. When yield was less than 1%, it was indicated
as trace. n/o=Not observed. Experiments were performed in triplicate. [b] Yields and TON determined by GC using mesitylene as an internal standard;
[c] Yields of 1-adamatanol and 2-adamantanone; [d] Sum of TONs of acetoxylated products; [e] Single run.
3
products. The acetoxylation of C(sp )À H in benzylic acetals
that the reaction conditions lead to larger TONs for adamantane
than for cyclooctane, we can ascribe the higher reactivity to the
ability to stabilize a carbocation/carbocation character, which
would arise from hydride transfer. We further probed our
computational finding by conducting competition experiments
for the oxidation of cyclooctane and adamantane [See support-
ing information Table S9]. Under the reaction conditions listed
in Tables 1 and 2 similar product ratios (1:2.4 favoring
adamantane) were observed when compared with the individ-
ual experiments shown above. At first glance, this might
suggest very similar reactivity of both substrates, however, the
studied substrates have quite different solubility in DCE under
the reaction conditions (see Figure S1). Adamantane, which we
would, based on our calculations, expect to preferentially react,
exhibited substantially lower solubility. Therefore, to allow for
an appropriate comparison we lowered the substrate concen-
trations. When the solubility of adamantane was sufficient we
indeed observed preferential acetoxylation of adamantane
(1:3.3 favoring adamantane). This observation is in line with the
calculations shown in Table 3 and corroborates our assignment
of hydride transfer. This may be further substantiated by the
observation of the group of de Bruin that amination of the
[16]
using PhI(OAc)2 has indeed been reported.
Removal of
oxygen almost fully prevented this. We thus attribute the
formation of acetoxylated products to a gold-catalyzed process.
We again precluded the involvement of acid catalysis by
replacing HAuBr with the potassium salt, which resulted in an
4
essentially unchanged TON for the acetoxylation. We further
precluded the involvement of acid by also probing the outcome
of this reaction when replacing the gold salt with a catalytic
amount of p-TsOH, which produced no meaningful amounts of
oxidized adamantane.
Based on the observed trends we may ask if the nature of
3
the C(sp )À H oxidation step can be further narrowed down, that
is, if either a proton transfer, proton coupled electron transfer
(
PCET) or a hydride transfer occurs in the initial functionalization
step. Based on the simple stability of the corresponding
carbocations, radicals and anions of adamantane and cyclo-
octane, the observed reactivity may be attributed through a
comparison of reactivity trends. In principle, one could follow
the general trends as outlined in organic chemistry text books,
3
where the tertiary carbocation derived from the C(sp )À H bond
is more stable than the one derived from the secondary one
and vice versa for the carbanion. With the reported experimen-
tal BDEs (vide supra) we might expect a scenario where the
energetic difference is small. As we are comparing trends for
two specific molecules, we decided to compute the relative
3
C(sp )À H bonds in 9,10-dihydro-9-heteroanthracenes is possible
Table 3. Computed relative stabilities.
[17]
stabilities using the M06-2X functional in combination with
the def2-TZVPPD basis set and mimicked solvation effects of
dichloroethane with the PCM solvation model.
[18]
[19]
A detailed
description of the computational details can be found in the
supporting information.
[a]
À 1
Adamantane vs. Cyclooctane
ΔEZPE [kcal mol ]
We find that for both the anion and the radical form,
cyclooctane provides the more stable structure. In contrast, the
carbocation is more favored for adamantane. This is mostly in
line with our expectation, only differing in the stability of the
radicals, which suggest that the BDEs are slightly more different
than the reported experimental values listed above. If we recall
Carbocation
Radical
Anion
6.0
À 6.4
À 4.0
[
a] A positive value indicates that the adamantane based structure is
preferred and a negative value that the cyclooctane based structure is
preferred for the species with the cleaved CÀ H bond.
ChemCatChem 2021, 13, 1–6
www.chemcatchem.org
3
© 2021 The Authors. ChemCatChem published by Wiley-VCH GmbH
��
These are not the final page numbers!

Communications
doi.org/10.1002/cctc.202100804
ChemCatChem
[20]
with PhINTs via initial hydride transfer. Notably, this reaction
does not require the addition of a catalyst for activation of the
hypervalent iodine reagent. In the present case we therefore
propose that the actual role of gold can be attributed to Lewis-
Keywords: Acetoxylation · Gold Catalysis · Hydride Transfer ·
Hydrocarbon Oxidation
acid activation of PhI(OAc) , resulting in enhanced electro-
philicity allowing for hydride transfer.
2
[1] For representative reviews see: a) K. Godula, D. Sames, Science 2006,
312, 67–72; b) W. R. Gutekunst, P. S. Baran, Chem. Soc. Rev. 2011, 40,
1976–1991; c) J. Yamaguchi, A. D. Yamaguchi, K. Itami, Angew. Chem.
In summary, we find that the series of experiments that we
report here, while TONs are humble, clearly demonstrates the
capability of gold to activate oxidants for the functionalization
Int. Ed. 2012, 51, 8960–9009; Angew. Chem. 2012, 124, 9092–9142;
d) N. J. Gunsalus, A. Koppaka, S. H. Park, S. M. Bischof, B. G. Hashiguchi,
R. A. Periana, Chem. Rev. 2017, 117, 8521–8573.
3
[2] For representative reviews see: a) J. Wencel-Delord, T. Droge, F. Liu, F.
Glorius, Chem. Soc. Rev. 2011, 40, 4740–4761; b) F. Roudesly, J. Oble, G.
Poli, J. Mol. Catal. A 2017, 426, 275–296; c) Y. Park, Y. Kim, S. Chang,
Chem. Rev. 2017, 117, 9247–9301; d) P. Xu, W. Li, J. Xie, C. Zhu, Acc.
Chem. Res. 2018, 51, 484–495; e) P. Gandeepan, T. Muller, D. Zell, G.
Cera, S. Warratz, L. Ackermann, Chem. Rev. 2019, 119, 2192–2452.
of C(sp )À H bonds in simple hydrocarbons. Through comparison
of the relative reactivities of cyclooctane and adamantane, we
establish that a likely pathway for the functionalization of
3
C(sp )À H bonds is hydride transfer. In this case the role of gold
3
lies in the activation of the oxidant and not the C(sp )À H bonds.
[
3] For representative reviews see: a) A. S. K. Hashmi, R. Salathe, T. M. Frost,
L. Schwarz, J. H. Choi, Appl. Catal. A 2005, 291, 238–246; b) R. Skouta,
C. J. Li, Tetrahedron 2008, 64, 4917–4938; c) T. C. Boorman, I. Larrosa,
Chem. Soc. Rev. 2011, 40, 1910–1925; d) C. Nevado, T. deHaro, Synthesis
This is markedly different from the proposed mechanisms for
[9]
[10]
the acetoxylation of arenes reported by Wang and Michelet
employing very similar reaction conditions, where activation
likely proceeds through electrophilic activation of the arene by
gold and simple deprotonation results in the formation of a
gold-bound carbanion. If we compare to the two examples of
2
011, 2011, 2530–2539; e) S. Gaillard, C. S. Cazin, S. P. Nolan, Acc. Chem.
Res. 2012, 45, 778–787; f) L. Liu, J. Zhang, Chem. Soc. Rev. 2016, 45, 506–
516; g) M. R. Fructos, M. M. Diaz-Requejo, P. J. Perez, Chem. Commun.
2016, 52, 7326–7335; h) B. Ma, L. Liu, J. L. Zhang, Asian J. Org. Chem.
2018, 7, 2015–2025.
3
C(sp )À H functionalization reactions by Periana and co-
[4] J. Xie, C. Pan, A. Abdukader, C. Zhu, Chem. Soc. Rev. 2014, 43, 5245–
[6]
[7a]
5256.
workers, as well as Shul’pin et al., which we outlined in the
[
5] a) S. Bhunia, R. S. Liu, J. Am. Chem. Soc. 2008, 130, 16488–16489; b) I. D.
Jurberg, Y. Odabachian, F. Gagosz, J. Am. Chem. Soc. 2010, 132, 3543–
3552; c) G. H. Zhou, J. L. Zhang, Chem. Commun. 2010, 46, 6593–6595;
d) B. Bolte, F. Gagosz, J. Am. Chem. Soc. 2011, 133, 7696–7699; e) G. H.
Zhou, F. Liu, J. L. Zhang, Chem. Eur. J. 2011, 17, 3101–3104; f) J.
Barluenga, R. Sigueiro, R. Vicente, A. Ballesteros, M. Tomas, M. A.
Rodriguez, Angew. Chem. Int. Ed. 2012, 51, 10377–10381; Angew. Chem.
introduction, there is a fundamental difference in the nature of
3
the CÀ H breaking event compared to the C(sp )À H functionali-
zation reported here. For example, in the oxidative trans-
formation of methane to methanol reported by Periana and co-
[6]
workers, it is proposed that electrophilic activation, and thus
2
012, 124, 10523–10527; g) S. Bhunia, S. Ghorpade, D. B. Huple, R. S. Liu,
cleavage of the CÀ H bond via deprotonation, leads to a gold-
Angew. Chem. Int. Ed. 2012, 51, 2939–2942; Angew. Chem. 2012, 124,
2993–2996; h) A. S. K. Hashmi, M. Wieteck, I. Braun, M. Rudolph, F.
Rominger, Angew. Chem. Int. Ed. 2012, 51, 10633–10637; Angew. Chem.
2012, 124, 10785–10789; i) L. W. Ye, Y. Z. Wang, D. H. Aue, L. M. Zhang,
J. Am. Chem. Soc. 2012, 134, 31–34; j) M. M. Hansmann, M. Rudolph, F.
Rominger, A. S. K. Hashmi, Angew. Chem. Int. Ed. 2013, 52, 2593–2598;
Angew. Chem. 2013, 125, 2653–2659; k) D. D. Vachhani, M. Galli, J.
Jacobs, L. Van Meervelt, E. V. Van der Eycken, Chem. Commun. 2013, 49,
bound CH group as an intermediate, which subsequently leads
3
to CÀ O bond formation. This is contrasted by the report of
[
7a]
III
Shul’pin et al.
which proposes that a Au =O intermediate
3
leads to homolytic C(sp )À H bond cleavage resulting in a
carbon-centered radical that reacts further with O forming a
2
CÀ O bond. The results reported here, which we propose to
occur via hydride transfer, therefore complete the full spectrum
of different CÀ H bond breaking processes reaching from proton
transfer, PCET and hydride transfer. The presented vista on
7
3
171–7173; l) X. Wu, S. S. Chen, Y. Hu, L. Z. Gong, Org. Lett. 2014, 16,
820–3823; m) H. V. Adcock, E. Chatzopoulou, P. W. Davies, Angew.
Chem. Int. Ed. 2015, 54, 15525–15529; Angew. Chem. 2015, 127, 15745–
1
5749; n) P. Moran-Poladura, E. Rubio, J. M. Gonzalez, Angew. Chem. Int.
Ed. 2015, 54, 3052–3055; Angew. Chem. 2015, 127, 3095–3098; o) Y. L.
Wang, Z. T. Zheng, L. M. Zhang, J. Am. Chem. Soc. 2015, 137, 5316–5319;
p) F. Jaroschik, A. Simonneau, G. Lemiere, K. Cariou, N. Agenet, H.
Amouri, C. Aubert, J. P. Goddard, D. Lesage, M. Malacria, Y. Gimbert, V.
Gandon, L. Fensterbank, ACS Catal. 2016, 6, 5146–5160; q) D. Y. Li, W.
Fang, Y. Wei, M. Shi, Chem. Eur. J. 2016, 22, 18080–18084; r) Y. Liu, Z. Z.
Yu, Z. J. Luo, J. Z. Zhang, L. Liu, F. Xia, J. Phys. Chem. A 2016, 120, 1925–
3
C(sp )À H functionalization provides an alternative view of the
role of gold in the functionalization of hydrocarbons and has
the potential to systematically categorize this class of reactions
in the field of gold catalysis.
1
2
932; s) Y. L. Wang, M. Zarca, L. Z. Gong, L. M. Zhang, J. Am. Chem. Soc.
016, 138, 7516–7519; t) S. Tsupova, M. Rudolph, F. Rominger, A. S. K.
Acknowledgements
Hashmi, Chem. Eur. J. 2017, 23, 12259–12263; u) P. D. Nahide, J. O. C.
Jimenez-Halla, K. Wrobel, C. R. Solorio-Alvarado, R. O. Alvarado, B.
Yahuaca-Juarez, Org. Biomol. Chem. 2018, 16, 7330–7335; v) X. Yin, G.
Zuccarello, C. Garcia-Morales, A. M. Echavarren, Chem. Eur. J. 2019, 25,
JEMNK acknowledges access to computational facilities at the
Peregrine high-performance computing cluster (University of
Groningen) and access to the national computing facilities
provided by the Netherlands Organisation for Scientific Research
9485–9490.
[6] C. J. Jones, D. Taube, V. R. Ziatdinov, R. A. Periana, R. J. Nielsen, J.
Oxgaard, W. A. Goddard, Angew. Chem. Int. Ed. 2004, 43, 4626–4629;
Angew. Chem. 2004, 116, 4726–4729.
7] a) G. B. Shul’pin, A. E. Shilov, G. Suss-Fink, Tetrahedron Lett. 2001, 42,
7253–7256; b) M. P. de Almeida, L. M. D. R. S. Martins, S. A. C. Carabi-
neiro, T. Lauterbach, F. Rominger, A. S. K. Hashmi, A. J. L. Pombeiro, J. L.
Figueiredo, Catal. Sci. Technol. 2013, 3, 3056–3069; c) S. A. C. Carabi-
neiro, L. M. D. R. S. Martins, A. J. L. Pombeiro, J. L. Figueiredo, Chem-
CatChem 2018, 10, 1804–1813; for a review on heterogenous catalysis
see:; d) S. A. C. Carabineiro, Front. Chem. 2019, 7, 702.
(NWO project number 17664). JEMNK acknowledges funding from
[
the Netherlands Organisation for Scientific Research (NWO START-
UP grant).
Conflict of Interest
[
[
8] M. Lovisari, A. R. McDonald, Inorg. Chem. 2020, 59, 3659–3665.
9] D. Qiu, Z. Zheng, F. Mo, Q. Xiao, Y. Tian, Y. Zhang, J. Wang, Org. Lett.
2011, 13, 4988–4991.
The authors declare no conflict of interest.
ChemCatChem 2021, 13, 1–6
www.chemcatchem.org
4
© 2021 The Authors. ChemCatChem published by Wiley-VCH GmbH
��
These are not the final page numbers!

Communications
doi.org/10.1002/cctc.202100804
ChemCatChem
[
[
10] A. Pradal, P. Y. Toullec, V. Michelet, Org. Lett. 2011, 13, 6086–6089.
[18] D. Rappoport, F. Furche, J. Chem. Phys. 2010, 133, 134105.
[19] a) J. Tomasi, B. Mennucci, R. Cammi, Chem. Rev. 2005, 105, 2999–3093;
b) G. Scalmani, M. J. Frisch, B. Mennucci, J. Tomasi, R. Cammi, V. Barone,
J. Chem. Phys. 2006, 124, 94107.
[20] N. P. van Leest, L. Grooten, J. I. van der Vlugt, B. de Bruin, Chem. Eur. J.
2019, 25, 5987–5993.
11] For reviews on the use of hypervalent iodine reagents see: a) V.
Zhdankin, P. J. Stang, Chem. Rev. 2008, 108, 5299–5358; b) A. Yoshimura,
V. V. Zhdankin, Chem. Rev. 2016, 116, 3328–3435; c) F. C. S. E. Silva, A. F.
Tierno, S. E. Wengryniuk, Molecules 2017, 22; d) X. Li, P. H. Chen, G. S.
Liu, Beilstein J. Org. Chem. 2018, 14, 1813–1825.
[
12] S. R. Guo, P. S. Kumar, Y. Q. Yuan, M. H. Yang, Eur. J. Org. Chem. 2016,
4
260–4264.
[
[
[
13] G. K. Cook, J. M. Mayer, J. Am. Chem. Soc. 1995, 117, 7139–7156.
14] K. U. Ingold, Chem. Rev. 1961, 61, 563–589.
15] X. S. Xue, P. J. Ji, B. Y. Zhou, J. P. Cheng, Chem. Rev. 2017, 117, 8622–
8
648.
Manuscript received: June 3, 2021
[
[
16] H. Aman, Y. H. Wang, G. J. Chuang, ACS Omega 2020, 5, 918–925.
17] Y. Zhao, D. G. Truhlar, Theor. Chem. Acc. 2008, 120, 215–241.
Revised manuscript received: July 13, 2021
Version of record online: ■■■, ■■■■
ChemCatChem 2021, 13, 1–6
www.chemcatchem.org
5
© 2021 The Authors. ChemCatChem published by Wiley-VCH GmbH
��
These are not the final page numbers!

COMMUNICATIONS
Gold catalysis: A protocol for the
T. G. Jo, Dr. J. E. M. N. Klein*
– 6
3
direct acetoxylation of C(sp )À H
1
bonds of saturated hydrocarbons
using simple gold salts (e.g. HAuBr4)
3
Gold-Catalyzed Direct C(sp )À H Ace-
toxylation of Saturated Hydrocar-
bons
is reported. PhI(OAc) serves as the
2
oxidant and this transformation is
proposed to proceed via hydride
transfer as the key step.