Enantiocomplementary decarboxylative hydroxylation combining photocatalysis and whole-cell biocatalysis in a one-pot cascade process

Article abstract of DOI:10.1039/c9gc00098d

Designing a green, highly efficient and stereoselective catalytic system to generate valuable enantioenriched products is a long-standing goal in green chemistry. Here, we report a one-pot cascade combining photocatalysts with (R)- or (S)-selective ketoreductases for the decarboxylative carbonylation of carboxylic acids and the subsequent bioreduction to generate valuable chiral alcohols. Using this approach, various chiral alcohols with complementary (R)- or (S)-configurations were prepared with good yields (up to 93%) and excellent stereoselectivity (up to 99% ee). Such a photochemo-enzymatic one-pot whole-cell process combines the advantages of both photocatalysts and enzyme catalysts and provides a mild, green, metal-free and highly stereoselective alternative in asymmetric decarboxylative hydroxylation reactions.

Full text of DOI:10.1039/c9gc00098d

View Article Online
View Journal
Green
Chemistry
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: J. Xu, M. Arkin, Y.
Peng, W. Xu, H. Yu, X. F. Lin and Q. Wu, Green Chem., 2019, DOI: 10.1039/C9GC00098D.
This is an Accepted Manuscript, which has been through the
Volume 18 Number
7 7 April 2016 Pages 1821–2242
Royal Society of Chemistry peer review process and has been
accepted for publication.
Green
Chemistry
Accepted Manuscripts are published online shortly after
Cutting-edge research for a greener sustainable future
www.rsc.org/greenchem
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1463-9262
CRITICAL REVIEW
G. Chatel et al.
Heterogeneous catalytic oxidation for lignin valorization into valuable
chemicals: what results? What limitations? What trends?
rsc.li/green-chem

Please do not adjust margins
Page 1 of 5
Green Chemistry
View Article Online
DOI: 10.1039/C9GC00098D
Journal Name
COMMUNICATION
Enantiocomplementary Decarboxylative Hydroxylation Combining
Photocatalysis and Whole-Cell Biocatalysis in One-pot Cascade
Process
Received 00th January 20xx,
Accepted 00th January 20xx
Jian Xua, Mamatjan·Arkina, Yongzhen Penga, Weihua Xua, Huilei Yub, Xianfu Lina and Qi Wua*
DOI: 10.1039/x0xx00000x
www.rsc.org/
Designing green, highly efficient and stereoselective catalytic which has been reported to convert salicylate into catechol.7
system to generate valuable enantioenriched products is a long- Nevertheless, these existing enzymes usually exhibit limited
standing goal in green chemistry. Here, we report a one-pot stereoselectivity, which limits their application in the
cascade combining photocatalysts with (R)- or (S)-selective production of enantiopure products.
ketoreductases for the decarboxylative carbonylation of carboxylic
Cascade reaction has become an increasing powerful
acids and the subsequent bioreduction to generate valuable chiral approach to achieve chiral compounds.8 Recently, some
alcohols. Using this approach, various chiral alcohols with cascade reaction protocols have been properly designed by
complementary (R)- or (S)-configurations were prepared with good combing photocatalysis and biocatalysis.9 For example,
yields (up to 93%) and excellent stereoselectivity (up to 99% ee). Hollmann and co-workers developed
a
selective
Such photochemo-enzymatic one-pot whole-cell process oxyfunctionalization by using a combination of photochemical
a
combines the advantages of both photocatalysts and enzyme water-oxidation catalysis and peroxygenase catalysis.10 More
catalysts and provides a mild, green metal-free and highly recently, Zhao and Hartwig reported a cooperative asymmetric
stereoselective alternative in asymmetric decarboxylative reaction which combines photocatalysts for isomerizing alkenes
hydroxylation reactions.
with ene-reductases for reducing carbon–carbon double bonds,
to generate valuable enantioenriched products.11 These
protocols achieved the dual-advantages of both photocatalysis
and biocatalysis. Inspired by photoinduced decarboxylative
functionalization, herein, we developed a one-pot cascade
process combining photocatalyst with ketoreductase (KRED) to
convert carboxylic acids into chiral alcohols (Scheme 1). After
optimization, the photocatalyst can completely convert
Decarboxylative hydroxylation is an important transformation
in organic synthesis. Over the past decades, a variety of
chemical approaches have been developed to achieve
decarboxylative hydroxylation, most of which are based on
organometallic catalysts such as Pb (IV) and Mn (III),1 and may
cause issues related to heavy metal pollution. Photocatalysis
has evolved over the last decade into a widely used method in
carboxylic acids into ketones via
a
decarboxylative
organic
synthesis.2
Photoinduced
decarboxylative
carbonylation process. The intermediate ketones can be
subsequently reduced by (R)- or (S)-selective KRED in whole-cell
system respectively, to generate chiral alcohols with high
optical purity and specified configurations.
functionalization has been used to construct a vast array of
functional molecules,3 such as decarboxylative conjugate
addition,4 fluorination5 and borylation.6
Biocatalysis offers an alternative approach to gain functional
compounds with high efficiency and environmental affinity.
However, to the best of our knowledge, natural enzymes have
been rarely found capable of catalyzing decarboxylation
hydroxylation. One example is Salicylate hydroxylase (SALH),
The first challenge that needs to be addressed in the design
of such cascade reaction is to find a photocatalytic system
capable of catalyzing decarboxylative carbonylation in aqueous
phase so that the photocatalytic system may be compatible
with biocatalysts.
Previous studies showed that benzylic substrates can be
efficiently converted to acetophenone13 by using Riboflavin as a
highly biocompatible photocatalyst.12 The key step in these
reactions was the formation of benzylic radical. Therefore,
a. Department of Chemistry, Zhejiang University, Hangzhou 310027 (China)
E-mail: llc123@zju.edu.cn, wuqi1000@163.com
b. State Key Laboratory of Bioreactor Engineering, East China University of Science
and Technology, Shanghai 200237 (China)
E-mail: huileiyu@ecust.edu.cn
†Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here. See DOI:
10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
Green Chemistry
Page 2 of 5
COMMUNICATION
Journal Name
Table
1 Reaction optimization for the photocatalytic decarboxylative
View Article Online
OH
carbonylationa
DOI: 10.1039/C9GC00098D
)-selective
KRED
R
(
(R)-alcohol
OH
10% photocatalyst,
Whole-cell
PC, blue LEDs
RT, Air, Water
OH
O
blue LEDs
OH
O
O
(
+
S)
-selective
KRED
RT, Air, Water
O
OH
1a
2a
3a
(S)-alcohol
Entry
PC
Yield of 2a (%) b
Yield of 3a (%) b
Scheme 1 The combination of photocatalyst (PC) and KRED in a cascade reaction.
1
2
3
4
5
6
7
8
Riboflavin
Eosin Y
SAS
54
0
41
0
we hypothesized the same radical intermediate might be
formed by decarboxylation, followed by capturing O2 and then
being converted into the corresponding ketones. 2-
Phenylpropanoic acid (1a) was tested as a model substrate
under a range of reaction conditions (Table 1). After 12 hrs’
irradiation with blue LEDs at room temperature with an
addition of 10 mol% Riboflavin, the conversion of 1a could reach
almost 100%. The yield of the desired product 2a was only 54%
and an alcohol byproduct 3a was formed in a yield of 40%. This
byproduct could affect the stereoselectivity of the reduction of
ketone by KRED in the next step (Table 1, entry 1). The
formation of alcohol byproduct is likely owing to the fact that
the oxidability of triplet-excited Riboflavin (Ered= 1.7 V (vs. NHE)
at pH 714) was not strong enough. To solve this problem, other
potential photocatalysts were also tested for the model
reaction. To our delight, when sodium anthraquinone sulfonate
(SAS)15 was introduced as the photocatalyst, the yield of 2a was
raised up to 98% in water (Table 1, entries 3 and 8). Then, we
optimized the reaction conditions for the reduction of 2a. The
results showed that photocatalyst, air and light source (Table 1,
entries 4, 5 and 6) were essential to this reaction. When water
was used as a sole solvent, the yield of 2a declined significantly,
which may be caused by the low solubility of 2-phenylpropanoic
acid in water (Table 1, entry 7). We further reduced the dosage
of SAS to improve the efficiency (Table 1, entries 9, 10), and an
ideal yield and selectivity of 2a could also be achieved using SAS
as a photocatalyst at a concentration of 5 mol%. Stern−Volmer
fluorescence quenching experiments revealed the excited SAS
was diminished by 1a (Fig. S2†).
98
0
2
SAS c
0
-
0
0
SAS d
SAS e
SAS f
<5
56
98
95
55
n.d.
12
<1
<2
5
9
SAS (5 %) f
SAS (2.5 %) f
10
a Reaction conditions: 0.06 mmol 2-Phenylpropionic acid (1a) was dissolved in 50 μL
acetonitrile, then was added into 2 mL water with PC (0.006 mmol, 10 mol%), under
the irradiation with blue LEDs for 12 h at r.t.. b Determined by chiral GC. c Without
LEDs. d Without air. e Without acetonitrile. f Irradiation time: 18 h.
OH
HO
OH
COOH
Br
O
OH
N
Br
SO3Na
N
N
O
NH
HO
O
O
Br
Br
O
O
Riboflavin
Eosin Y
SAS
Table 2 Scope of the benzylic decarboxylation carbonylationa,b
R2
R2
OH
SAS, blue LEDs
O
R1
R1
O
RT, Air, Water
1a-l
2a-l
O
O
O
O
F
Applying the optimized reaction conditions, we next
investigated the scope of substrate of this photoinduced
process. A series of benzylic carboxylic acids were successfully
converted into the corresponding ketones with high yields
(Table 2). The substrate (1h) containing one hydroxyl
substituent, which otherwise could be easily oxidized, also be
tolerated and product 2h was obtained with 89% yield.
However, the yields of alkyl substituted 2-aryl propionic acids
(1c, 1j) slightly decreased due to benzylic C−H oxidation.15a
Interestingly, unactivated aliphatic acid (1l) also displayed
moderate reaction activity and the product 2l was obtained
with 35% yield. Finally, a scale-up reaction of 1a (6.7 mmol, 1 g)
was performed and the product 2a was obtained in a
satisfactory yield (92%) after 30 hrs’ irradiation.
2a, 95% yield
2b, 99% yield
2c, 82% yield
2d, 93% yield
OH
Cl
Cl
O
O
O
O
Cl
2e, 96% yield
2f, 95% yield
O
2g, 96% yield
2h, 89% yield
O
O
O
O
O
2i, 91% yield
2j, 80% yield
2k, 95% yield
2l, 35% yield
a Standard reaction conditions: 0.06 mmol carboxylic acid (1a) was dissolved
in 50 μL acetonitrile, then was added into 2 mL water with SAS (10 mol%),
under the irradiation with blue LEDs for 18 h at r.t, the reaction time could
be properly extended to ensure no residual alcohols.
determined by chiral GC or HPLC.
b
Yields were
To implement the one-pot protocol, the selectivity and
activity of KRED for catalyzing the asymmetric reduction of the
ketones have to be enhanced. We chose Carbonyl reductase
from Kluyveromyces thermotolerans (KtCR) as a model enzyme
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 5
Green Chemistry
Please do not adjust margins
Journal Name
COMMUNICATION
buffer (pH=6.5) and added into the photocatalytic mixture. To
View Article Online
PC, blue LEDs
OH
O
our delight, this cascade system proceDeOdeI:d10.s1m03o9o/Ct9hGlyC0w0i0t9h8Da
high yield (90%) and selectivity (99% ee). However, the
requirement of a stoichiometric amount of the expensive
cofactors (NADPH) as an electron donor strongly hampered the
further application of this cascade process. The whole-cell
reaction system, wherein the ketone reduction is supported by
the intracellular regeneration of NADPH, is an effective
approach to overcome this limitation.17 Thus, we performed
this whole-cell transformation with the above-mentioned
photocatalytic mixture by adding 10 mL of the culture medium
of KtCR (OD600=6) (Fig. 2). As expected, 2a was able to permeate
the cell membrane, and the whole-cell one-pot reaction was
carried out smoothly to generate the product (R)-3a in excellent
yield (92%) and selectivity (99% ee).
RT, Air, Water
3a
2a
Based on the successful one-pot stereoselective
decarboxylative hydroxylation process, we tried the aryl acids
with different substituent groups to examine the scope of the
substrate of the reaction. For the PC/KtCR-catalyzed one-pot
reactions (Table 3), various substituents on the phenyl rings
Fig. 1 Photocatalytic oxidation of phenylethanol. Standard reaction conditions: 0.06
mmol carboxylic acid (3a) was dissolved in 50 μL acetonitrile, then was added into 2 mL
water with SAS (10 mol%), under the irradiation with blue LEDs
Table 3 Substrate scope of (R)-selective one-pot decarboxylative hydroxylation.a,b
R2
R2
R2
OH
KtCR Whole-Cell
SAS, blue LEDs
O
OH
R1
R1
R1
O
RT, Air, Water
-3a-k
(R)
1a-k
2a-k
OH
OH
OH
(R)-3a
(R)-3b
(R)-3c
92 (85)% yield,
99 % ee.
93 (80)% yield,
99% ee
67 (51)% yield,
91% ee.
Cl
OH
OH
OH
Cl
F
Fig. 2 One-pot decarboxylative hydroxylation in whole-cell reaction system.
(R)-3d
(R)-3e
89 (77)% yield, 86%
(R)-3f
85 (73)% yield,
97% ee.
91 (81)% yield,
99% ee.
ee.
OH
for the screening of the cascade-reaction conditions, which was
identified with satisfactory (R)-selectivity.16 The initial study was
conducted in a one-pot reaction. Unfortunately, the results
revealed that the cascade system in one-pot was strongly
inhibited. Product 3a was not detected. A possible explanation
was that the product 3a may be formed and then oxidized by
the excited SAS. To test this hypothesis, we designed an
experiment converting 3a to 2a. As shown in Fig. 1, the
formation of 2a increased gradually with time under the
irradiation with blue LEDs. Thus, by extracting 2a from the
decarboxylative carbonylation reaction system and then
conducting a separated reduction reaction, (R)-3a was obtained
with 80% yield.
However, extraction with organic solvents not only
complicated the reaction operation but was also environment
unfriendly. In order to simplify the process, we decided to look
for an alternative approach to carrying out a one-pot reaction.
In the improved approach, SAS (10 mol%) was dissolved in 2 ml
water with 1a (30 mM). After irradiation with blue LEDs for 18
hours, KtCR and NADPH (1.5 eq to 1a) were dissolved in 10 ml
Cl
OH
OH
OH
O
(R)-3g
91 (82)% yield,
95% ee.
(S)-3h c
85 (65)% yield,
99% ee.
(R)-3i
92 (81)% yield,
94% ee.
OH
OH
O
(R)-
(R)-3k
63% yield,
50% ee.
3j
69% yield,
15% ee.
a
b
Yield and ee value were determined by chiral GC or HPLC. Isolated yield
of scaling-up reaction were given in parentheses. c The R/S assignment was
changed in accordance with the Cahn-Ingold-Prelog priority rules.
such as methyl (3c), halogen (3d-g), and methoxyl (3i) were all
tolerated and showed excellent (R)-selectivity. Moreover,
substrates with methyl (3b) or hydroxyl (3h) substituents on the
α-methyl position also displayed satisfactory yields and
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
Green Chemistry
Page 4 of 5
COMMUNICATION
Journal Name
reaction conditions (anhydrous and anaerobic systems) are
selectivity. The reactions were also easily scaled up to 200 mg
with good yields and high stereoselectivity (Table 3, ESI†).
Replacing the (R)-selective KRED (KtCR) with an (S)-selective
KRED (YueD from Bacillus18) provided mainly (S)-alcohols
through the above one-pot cascade reaction (Table 4). Most of
the tested aromatic carboxylic acids could be converted into
corresponding (S)-alcohols with high yields and ee values.
Interestingly, for o-chlorinated substrate (1f), PC/YueD-
catalyzed system displayed the same (R)-selective preference as
did the PC/KtCR system (Table 4). However, m-chlorinated
substrate (1g) and α-hydroxy-substituted substrate (1h) were
not accepted by YueD. In addition, the one-pot cascade system
of PC/YueD also demonstrated high (S)-selectivity for non-
steroidal anti-inflammatory drugs such as ibuprofen and
naproxen (Table 4, 3j and 3k), which was not selectively
recognized by KtCR.
View Article Online
often needed.19 In contrast, the whole cell bioreduction method
DOI: 10.1039/C9GC00098D
in this work is a much milder and more efficient approach to
obtain chiral alcohols, without the addition of the expensive
cofactor NADPH.
Conclusions
In summary, an enantiocomplementary decarboxylative
hydroxylation combining photocatalyst and ketoreductase in
one-pot whole-cell cascade process was demonstrated for the
first time. A series of racemic carboxylic acids can be
successfully converted into the corresponding chiral alcohols
with either (R)- or (S)-configuration in accordance with the
selectivity of the KREDs used. This photochemo-enzymatic one-
pot whole-cell cascade process is highly stereoselective, metal-
free and cost effective, and conducted under mild conditions
such as aqueous phase, room temperature, with O2 as the sole
oxidant, and without the addition of the expensive cofactor
NADPH, enhancing the concept of green chemistry. All these
advantages indicate the photochemo-enzymatic one-pot
transformation may have great potential in green synthetic
chemistry and sustainable development.
Table 4 Substrate scope of (S)-selective one-pot decarboxylative hydroxylation.a,b
R2
R2
R2
OH
YueD Whole-Cell
SAS, blue LEDs
O
OH
R1
R1
R1
O
RT, Air, Water
-3a-k
(S)
1a-k
2a-k
OH
OH
OH
(S)-3a
71(62)% yield,
99 % ee.
(S)-3b
61% yield,
98% ee
(S)-3c
Conflicts of interest
There are no conflicts to declare.
71% yield,
97% ee.
Cl
OH
OH
OH
Acknowledgements
Cl
F
(S)-3d
74% yield,
99% ee.
(S)-3e
81% yield,
95% ee.
(R)-3f
91% yield,
99% ee.
The financial support from National Natural Science Foundation
of China (21574113, 21472169), Zhejiang Provincial Natural
Science Foundation (LY19B020014) and the Fundamental
Research Funds for the Central Universities (2018QNA3010) is
gratefully acknowledged. The authors thank Dr. Meilan Huang
and Dr. Yangmei Li for their fruitful discussion.
OH
Cl
OH
OH
OH
O
(S)-3g
(R)-3h c
(S)-3i
n.d.
n.d.
31% yield,
99% ee.
Notes and references
OH
OH
1. (a) E. J. Corey and J. Casanova, J. Am. Chem. Soc., 1963, 85, 165-
169; (b) J. K. Kochi, J. D. Bacha and T. W. Bethea, J. Am. Chem.
Soc., 1967, 89, 6538-6547; (c) V. Mirkhani, S. Tangestaninejad, M.
Moghadam and M. Moghbel, Bioorgan. Med. Chem., 2004, 12,
903-906.
2. (a) D. Ravelli, S. Protti and M. Fagnoni, Chem. Rev., 2016, 116,
9850-9913; (b) D. M. Schultz and T. P. Yoon, Science, 2014, 343,
985-994; (c) M. Parasram and V. Gevorgyan, Chem. Soc. Rev.,
2017, 46, 6227-6240; (d) D. Cambie, C. Bottecchia, N. J. W.
Straathof, V. Hessel and T. Noel, Chem. Rev., 2016, 116, 10276-
10341; (e) J. P. Goddard, C. Ollivier and L. Fensterbank, Accounts
Chem. Res., 2016, 49, 1924-1936; (f) N. A. Romero and D. A.
Nicewicz, Chem. Rev., 2016, 116, 10075-10166.
3. (a) Z. Zuo, H. Gong, W. Li, J. Choi, G. C. Fu and D. W. C. MacMillan,
J. Am. Chem. Soc., 2016, 138, 1832-1835; (b) C. P. Johnston, R. T.
Smith, S. Allmendinger and D. W. C. MacMillan, Nature, 2016,
536, 322-325; (c) H.-T. Song, W. Ding, Q.-Q. Zhou, J. Liu, L.-Q. Lu
and W.-J. Xiao, J. Org. Chem., 2016, 81, 7250-7255; (d) J. Schwarz
and B. Konig, Green Chem, 2018, 20, 323-361.
O
(S)-3j
72 (58)% yield,
99% ee.
(S)-3k
53 (39)% yield,
92% ee.
a Yield and ee value were determined by chiral GC or HPLC. b Isolated yields
of scaling-up reaction were given in parentheses. c The R/S assignment was
changed in accordance with the Cahn-Ingold-Prelog priority rules.
Finally, we presented a preliminary comparison of our
photochemo-enzymatic one-pot process with other existing
routes. As shown in Table S1 (ESI†), our process afforded the
ketone products in the first step with relatively high yields and
reduced cost, compared with other reported decarboxylative
carbonylation processes dependent on heavy metal catalysts
and organic solvents. Additionally, in the second step,
traditional reduction methods usually require metal complexes
as catalysts, which are difficult to be synthesized and extreme
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 5
Green Chemistry
Please do not adjust margins
Journal Name
COMMUNICATION
4. (a) L. L. Chu, C. Ohta, Z. W. Zuo and D. W. C. MacMillan, J. Am.
Chem. Soc., 2014, 136, 10886-10889; (b) H. Cao, H. M. Jiang, H.
Y. Feng, J. M. C. Kwan, X. G. Liu and J. Wu, J. Am. Chem. Soc.,
2018, 140, 16360-16367.
Wang, G. Yang, F. Xie and W. Zhang, Org. Lett., 2018, 20, 6135-
View Article Online
6139.
DOI: 10.1039/C9GC00098D
5. (a) S. Ventre, F. R. Petronijevic and D. W. C. MacMillan, J. Am.
Chem. Soc., 2015, 137, 5654-5657; (b) X. Wu, C. Meng, X. Yuan,
X. Jia, X. Qian and J. Ye, Chem Comm., 2015, 51, 11864-11867.
6. (a) C. Li, J. Wang, L. M. Barton, S. Yu, M. Q. Tian, D. S. Peters, M.
Kumar, A. W. Yu, K. A. Johnson, A. K. Chatterjee, M. Yan and P. S.
Baran, Science, 2017, 356(6342), eaam7355; (b) A. Fawcett, J.
Pradeilles, Y. Wang, T. Mutsuga, E. L. Myers and V. K. Aggarwal,
Science, 2017, 357, 283-286.
7. (a) T. Uemura, A. Kita, Y. Watanabe, M. Adachi, R. Kuroki and Y.
Morimoto, Biochem. Biophys. Res. Commun., 2016, 469, 158-
163; (b) X. Wang, Q. Hou and Y. Liu, Theor. Chem Acc., 2018, 137,
89.
8. (a) F. G. Mutti, T. Knaus, N. S. Scrutton, M. Breuer and N. J.
Turner, Science, 2015, 349, 1525-1529; (b) J. H. Schrittwieser, S.
Velikogne, M. Hall and W. Kroutil, Chem. Rev., 2018, 118, 270-
348.
9. (a) K. Lauder, A. Toscani, Y. Qi, J. Lim, S. J. Charnock, K. Korah and
D. Castagnolo, Angew. Chem.-Int. Edit., 2018, 57, 5803-5807; (b)
W. Zhang, B. O. Burek, E. Fernandez-Fueyo, M. Alcalde, J. Z. Bloh
and F. Hollmann, Angew. Chem.-Int. Edit., 2017, 56, 15451-
15455; (c) M. Mifsud, S. Gargiulo, S. Iborra, I. W. C. E. Arends, F.
Hollmann and A. Corma, Nature Commun., 2014, 5, 3145; (d) S.
Choudhury, J. O. Baeg, N. J. Park and R. K. Yadav, Angew. Chem.-
Int. Edit., 2012, 51, 11624-11628; (e) X. Guo, Y. Okamoto, M. R.
Schreier, T. R. Ward and O. S. Wenger, Chem Sci, 2018, 9, 5052-
5056.
10. W. Zhang, E. Fernandez-Fueyo, Y. Ni, M. van Schie, J. Gacs, R.
Renirie, R. Wever, F. G. Mutti, D. Rother, M. Alcalde and F.
Hollmann, Nature Catal., 2018, 1, 55-62.
11. Z. C. Litman, Y. Wang, H. Zhao and J. F. Hartwig, Nature, 2018,
560, 355-359.
12. F. Hollmann, A. Taglieber, F. Schulz and M. T. Reetz, Angew.
Chem.-Int. Edit., 2007, 46, 2903-2906.
13. B. Muehldorf and R. Wolf, Angew. Chem.-Int. Edit., 2016, 55, 427-
430.
14. C. Y. Lu, W. Z. Lin, W. F. Wang, Z. H. Han, S. Yao and N. Y. Lin, Phys.
Chem. Chem. Phys., 2000, 2, 329-334.
15. (a) W. Zhang, J. Gacs, I. Arends and F. Hollmann, ChemCatChem,
2017, 9, 3821-3826; (b) D. Petzold and B. Konig, Adv. Synth.
Catal., 2018, 360, 626-630.
16. G.-C. Xu, H.-L. Yu, X.-Y. Zhang and J.-H. Xu, Acs Catal., 2012, 2,
2566-2571.
17. (a) P. Both, H. Busch, P. P. Kelly, F. G. Mutti, N. J. Turner and S. L.
Flitsch, Angew. Chem.-Int. Edit., 2016, 55, 1511-1513; (b) M.
Karasawa, J. K. Stanfield, S. Yanagisawa, O. Shoji and Y.
Watanabe, Angew. Chem.-Int. Edit., 2018, 57, 12264-12269.
18. (a) Y. Ni, C. X. Li, H. M. Ma, J. Zhang and J. H. Xu, Appl. Microbiol.
Biotechnol., 2011, 89, 1111-1118; (b) Y. Ni, C. X. Li, L. J. Wang, J.
Zhang and J. H. Xu, Org. Biomol. Chem., 2011, 9, 5463-5468.
19. (a) Z. Zheng, Y. Cao, Q. Chong, Z. Han, J. Ding, C. Luo, Z. Wang, D.
Zhu, Q.-L. Zhou and K. Ding, J. Am. Chem. Soc., 2018, 140, 10374-
10381; (b) L. O. Nindakova, V. O. Strakhov and S. S. Kolesnikov,
Russ. J. Gen. Chem., 2018, 88, 199-207; (c) R. Huber, A. Passera
and A. Mezzetti, Organometallics, 2018, 37, 396-405; (d) I. A.
Utepova, P. O. Serebrennikova, M. S. Streltsova, A. A. Musikhina,
T. G. Fedorchenko, O. N. Chupakhin and A. P. Antonchick,
Molecules, 2018, 23; (e) F. Ling, S. Nian, J. Chen, W. Luo, Z. Wang,
Y. Lv and W. Zhong, J. Org. Chem., 2018, 83, 10749-10761; (f) Y.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins