Lipase-mediated selective oxidation of furfural and 5-hydroxymethylfurfural

Article abstract of DOI:10.1002/cssc.201200954

Furfural and 5-hydroxymethylfurfural (HMF) are important biomass-derived platform chemicals that can be obtained from the dehydration of lignocellulosic sugars. A possible route for the derivatization of furanics is their oxidation to afford a broad range of chemicals with promising applications (e.g., diacids, hydroxyl acids, aldehyde acids, monomers for novel polymers). Herein we explore the organic peracid-assisted oxidation of furanics under mild reaction conditions. Using lipases as biocatalysts, alkyl esters as acyl donors, and aqueous solutions of hydrogen peroxide (30% v/v) added stepwise, peracids are formed in situ, which subsequently oxidize the aldehyde groups to afford carboxylic acids with high yields and excellent selectivities. Furthermore, the use of an immobilized silicabased 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) affords the selective oxidation of the hydroxymethyl group of HMF to afford 2,5-diformylfuran. That product can be subsequently oxidized using again lipases for the in situ peracid formation to yield 2,5-furandicarboxylic acid, which is considered to be a key building block for biorefineries. These lipase-mediated reactions proceeded efficiently even with high substrate loadings under still non-optimized conditions. Overall, a proof-of-concept for the oxidation of furanics (based on in situ formed organic peracids as oxidants) is provided.

Full text of DOI:10.1002/cssc.201200954

CHEMSUSCHEM
FULL PAPERS
DOI: 10.1002/cssc.201200954
Lipase-Mediated Selective Oxidation of Furfural and 5-
Hydroxymethylfurfural
[
a]
Monika Krystof, Marꢀa Pꢁrez-Sꢂnchez, and Pablo Domꢀnguez de Marꢀa*
Furfural and 5-hydroxymethylfurfural (HMF) are important bio-
mass-derived platform chemicals that can be obtained from
the dehydration of lignocellulosic sugars. A possible route for
the derivatization of furanics is their oxidation to afford
a broad range of chemicals with promising applications (e.g.,
diacids, hydroxyl acids, aldehyde acids, monomers for novel
polymers). Herein we explore the organic peracid-assisted oxi-
dation of furanics under mild reaction conditions. Using lipases
as biocatalysts, alkyl esters as acyl donors, and aqueous solu-
tions of hydrogen peroxide (30% v/v) added stepwise, peracids
are formed in situ, which subsequently oxidize the aldehyde
groups to afford carboxylic acids with high yields and excellent
selectivities. Furthermore, the use of an immobilized silica-
based 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) affords the
selective oxidation of the hydroxymethyl group of HMF to
afford 2,5-diformylfuran. That product can be subsequently oxi-
dized using again lipases for the in situ peracid formation to
yield 2,5-furandicarboxylic acid, which is considered to be
a key building block for biorefineries. These lipase-mediated re-
actions proceeded efficiently even with high substrate loadings
under still non-optimized conditions. Overall, a proof-of-con-
cept for the oxidation of furanics (based on in situ formed
organic peracids as oxidants) is provided.
Introduction
The acid-catalyzed triple dehydration of lignocellulosic-based
sugars (mostly C xylose and C glucose) leads to the formation
their selective oxidation to a number of highly functionalized
carboxylic acids, dialdehydes, hydroxyl acids, among others,
which may well serve as monomers for innovative biobased
5
6
of biomass-derived furanics, namely furfural and 5-hydroxy-
methylfurfural (HMF) from xylose and glucose, respectively.
These chemicals are considered
[1–3]
products, such as polymers or resins (Scheme 1).
promising building blocks for
their subsequent derivatization
and valorization into a broad
range of useful chemicals and
[
1–3]
biofuel constituents.
The
quest for more selective and en-
vironmentally friendly catalytic
manufacturing of those biomass-
derived furanics is challenging
due to their high propensity to
trigger, for example, oligomeriza-
Scheme 1. Possible products derived from the oxidative valorization of furfural and HMF.
tions, rehydrations, or humin for-
mation, which ultimately reduce
the overall selectivities and yields, often with an unacceptable
level of waste formation. Recent literature provides an excel-
For the oxidation of biomass-derived furanics, several
chemocatalytic strategies have been reported for the conver-
[
4]
[5]
lent overview of these efforts.
Among many other promising options,
orization of the aforementioned biomass-derived furanics is
sions of furfural (1a) to furoic acid (2) and of HMF (1b) to 5-
[
1–3]
[6]
an important val-
hydroxymethylfuroic acid (3), as well as to 2,5-diformylfuran
[7]
[8]
(4) and to 5-formylfuroic acid (5). Furthermore, the full oxi-
dation of HMF to afford 2,5-furandicarboxylic acid (6) is highly
relevant to many promising applications (e.g., as monomer for
[
a] M. Krystof, Dr. M. Pꢀrez-Sꢁnchez, Dr. P. Domꢂnguez de Marꢂa
Institut fꢃr Technische und Makromolekulare Chemie (ITMC)
RWTH Aachen University
[
1,3]
new polymeric materials).
Chemocatalytic approaches for its
[
3b,7e,8a,9]
synthesis have been extensively studied as well.
Several
Worringerweg 1, 52074 Aachen (Germany)
Fax: (+49)241-8022177
E-mail: dominguez@itmc.rwth-aachen.de
strategies using whole-cells (biotransformations) and enzymes
have also been reported. Resting cells of Nocardia corallina dis-
[10]
played the oxidation of 1a to 2 and growing cells of Pseu-
domonas putida can perform the selective oxidation of HMF to
Supporting Information for this article is available on the WWW under
http://dx.doi.org/10.1002/cssc.201200954.
ꢃ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemSusChem 2013, 6, 826 – 830 826

CHEMSUSCHEM
FULL PAPERS
www.chemsuschem.org
[
11]
6
.
Likewise, several enzymatic methods involving oxidases
Table 1. Lipase-mediated oxidation of furfural to furoic acid. Conditions:
[
12]
and chloroperoxidases have been assessed.
À1
furfural (50 mm), CAL-B (10 mgmL ), different solvent ratios and temper-
Overall, the oxidation of furfural and HMF is challenging due
to the high reactivity of both substrates and formed products
and intermediates. Oxidative conditions must be strong
enough to allow oxidations to occur, but mild enough to
secure an acceptable selectivity and a diminished by-product
formation. On this basis, a broad number of oxidants have
been reported in the literature (O , CO , H O , tBuOOH) for the
atures, 24 h reaction time. Reactions without CAL-B did not show any
conversion of furfural to furoic acid.
[a]
2
[b]
Entry
Solvent
Addition of H
2
O
T
[8C]
Yield
[%]
2
2
2
2
[
5–12]
aforementioned catalytic systems.
Surprisingly, to our
1
2
3
4
5
6
7
EtOAc (neat)
EtOAc (neat)
3ꢄ1 equiv
3ꢄ1 equiv
3ꢄ1 equiv
3ꢄ1 equiv
6ꢄ1.6 equiv
3ꢄ1 equiv
3ꢄ1 equiv
30
60
40
40
40
40
40
5
33
50
60
91
27
0
knowledge organic peracids (derived from carboxylic acids)
have never been reported for the oxidation of furanics. A pos-
sible explanation might be the high reactivity of peracids,
which hampers its storage and transportation. Remarkably, the
expected oxidative mechanism of peracids (based on
EtOAc/tBuOH 3:1 (v/v)
EtOAc/tBuOH 1:1 (v/v)
EtOAc/tBuOH 1:1 (v/v)
EtOAc/tBuOH 1:100 (v/v)
tBuOH (neat)
[13]
a Baeyer–Villiger-type reaction over a carbonylic group)
[
2 2
a] Addition of aqueous H O (30% v/v), performed each hour until the
might lead to the selective oxidation of biomass-derived furan-
number of additions was completed. [b] Yield determined upon crystalli-
zation of furoic acid.
2
ics, whereby aldehydes (sp ) would be prone to such peracid-
3
driven oxidation, whereas alcohols (sp ) would not.
To probe this idea, peracids were generated in situ in catalyt-
ic amounts using lipases as biocatalysts and alkyl esters as acyl
donors upon addition of aqueous hydrogen peroxide (30%v/v)
under very mild reaction conditions (Scheme 2). The biocatalyt-
Peracetic acid, which is formed in situ using CAL-B, is able to
mildly oxidize furfural to afford furoic acid in moderate to ex-
cellent yields. Reactions conducted in neat ethyl acetate
(
EtOAc), acting both as acyl donor and solvent, led to lower
yields in furoic acid than processes performed with a mixture
[16]
of tert-butanol (tBuOH, as inert solvent for CAL-B) and ethyl
acetate (Table 1, entries 1 and 2 vs. entries 3–6). Moreover, fur-
ther addition of higher amounts of oxidant (Table 1, entry 5)
À1
led to even higher yields in furoic acid (ꢀ5 gL , 91%) with
excellent selectivity (100%). It must be noted that reaction
conditions can still be further optimized, for example, by as-
sessing enzyme loading, type of reactor, frequency of additions
of hydrogen peroxide. Likewise, the recent development of
highly robust immobilized lipases provides promising progno-
sis for its implementation in the production of low-added-
value products in an economic fashion because those im-
mobilized enzymes are largely stable for their reuse along pro-
Scheme 2. Envisaged lipase-catalyzed peracid formation to perform a chemo-
enzymatic oxidation of biomass-derived furanics. Instead of esters, carboxylic
acids may also be directly used as substrates, thus leading to the in situ re-
[
14,15]
generation of the acyl donor.
[17]
longed reaction times. Moreover, the immobilization of the
lipase may contribute to deliver more resistant biocatalysts to
the action of hydrogen peroxide as recent literature has
ic promiscuity of lipases enables them to accept hydrogen per-
oxide as a nucleophile (instead of water or alcohols) in non-
aqueous solutions, affording organic peracids. Subsequently,
these peracids may perform in situ oxidations. Several oxida-
tive processes have been reported using this strategy (e.g.,
[18]
shown.
Encouraged by these successful results, the same reaction
media (acyl donor/tert-butanol, 1:1 v/v) and stepwise additions
of diluted hydrogen peroxide (30% v/v) were then applied for
the lipase-mediated oxidation of HMF using in this case either
ethyl acetate or ethyl butyrate as acyl donors. As a difference
in this case, HMF has two functional groups (alcohol and alde-
hyde), upon which a potential peracid-assisted oxidation might
in principle proceed (Figure 1).
[
14]
epoxidations, Baeyer–Villiger reactions), as well as for the se-
lective oxidative delignification of lignocellulose to afford en-
riched polysaccharide fractions and oxidized and dearomatized
[
15]
lignin oil.
Accordingly, the enzyme-mediated setup resulted successful-
ly also in the oxidation of HMF, notably yielding 3 (with excel-
lent yields) and its corresponding acetyl or butyl ester (99%
overall oxidative yield considering both products). The ob-
served esterification of 3 may be considered as a second reac-
tion catalyzed by CAL-B as well. The use of different acyl
donors (acetate or butyrate) did not lead to significant changes
in yields or in product distribution (Figure 1). Remarkably, no
Results and Discussion
Commercially available immobilized lipase B from Candida ant-
arctica (Immo-CAL-B) was used. In a first set of experiments,
the oxidation of 1 to 2 was assessed by adding stepwise differ-
ent amounts of aqueous hydrogen peroxide (diluted, 30% v/v)
and varying other parameters, such as the reaction media and
temperature (Table 1).
[19]
ꢃ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemSusChem 2013, 6, 826 – 830 827

CHEMSUSCHEM
FULL PAPERS
www.chemsuschem.org
Figure 2. Performance of TEMPO-catalyzed oxidation of HMF to yield 4.
Conditions: dichloromethane or ethyl acetate mixed with aq. NaOCl and KBr
(
2m), TEMPO (0.2 mmol), and HMF (10 mmol); reaction for 1 h at room tem-
perature (see the Supporting Information).
Figure 1. Lipase-mediated oxidation of HMF. Conditions: HMF (50 mm), CAL-
a number of times without observing loss in its catalytic activi-
ty (Figure 2). Therefore, a further heterogeneous flow-integrat-
ed process for producing 4 through this route may be envis-
aged to provide more sustainable tools for future biomass-
based processes.
À1
B (10 mgmL ), addition of aqueous H
2
O
2
(30% v/v) hourly. Reaction media:
acyl donor (ethyl acetate or butyrate)/tBuOH (1:1 v/v), 408C, 24 h. A blank re-
action without CAL-B did not show any conversion of HMF. Yield was deter-
1
mined by H NMR analysis upon evaporation of the solvent (see the Sup-
porting Information).
Once 4 was obtained (non-optimized conditions), the subse-
quent lipase-mediated oxidation of 4 to afford 6 was studied.
Reaction conditions analogous to those previously reported
(Table 1 and Figure 1) were used. The reaction was extremely
efficient and selective under these conditions, and quantitative
yields (with 100% selectivity) in 6 were achieved at concentra-
tions of 50mm for 4. After such successful results, substrate
loadings were increased to assess whether industrially sound
conditions could be realistic within this approach (Figure 3).
Accordingly, the reaction proceeded successfully with higher
yields in 6 even at substrate loadings of 150–200 mm. Never-
theless, low amounts of the intermediate oxidized acid alde-
traces of 4, 5, or 6 were found, thus proving the peracid-assist-
ed oxidative process to be chemoselective for the oxidation of
the aldehyde group of HMF. This lipase-mediated oxidation of
HMF is highly useful when challenging “semi-oxidized” struc-
tures such as 3 are pursued. Overall, results suggest that in situ
formed peracids are able to oxidize aldehyde groups but not
hydroxyl ones. Upon further optimization, the production of 3
might become relevant for future biomass-based processes, in
which efficient and selective reaction systems under mild con-
ditions are needed. A number of new uses (e.g., monomers for
polyesters) may be easily envisaged for such a compound.
Proceeding with our oxidative studies, the 2,2,6,6-tetra-
methylpiperidine-1-oxyl (TEMPO)-catalyzed organocatalytic oxi-
[
7f]
dation of HMF to 4 was subsequently assessed. TEMPO is an
[
20]
air-stable nitroxide radical, and oxidative conditions for the
conversion of alcohols to aldehydes using KBr and aqueous
NaOCl in dichloromethane are typically regarded as “Anelli
[
21]
conditions”. Herein, with emphasis on sustainable chemistry,
[
22]
a heterogeneous silica-based immobilized TEMPO was used
for the oxidation of HMF. In addition, dichloromethane was re-
placed by ethyl acetate with a dual purpose: first, the replace-
ment of chlorinated solvents by a biobased one was carried
out; and second, the anticipation of a potential combination
of the organocatalytic step with a subsequent lipase-mediated
oxidation of 4 in ethyl acetate as reaction media (Figure 2).
Under non-optimized conditions, TEMPO could selectively
oxidize HMF to 4, albeit still in low yields. The replacement of
dichloromethane by ethyl acetate led to an improvement in
yields when free TEMPO was used. The incorporation of im-
mobilized silica-based TEMPO in ethyl acetate turned out to be
successful as well. Although yields were slightly lower than
those observed for free TEMPO (under the same reaction con-
ditions) the heterogeneous catalysts could be reused
Figure 3. Product distribution of scaleup experiments with increasing con-
À1
centrations of 4. Conditions: 4 (50–200 mm), CAL-B (10 mgmL ), H
2
O
2
(
6ꢄ0.4 mmol, added after 0, 1, 2, 3, 4, and 5 h, up to 400 mm in total),
EtOAc/tBuOH (1:1 v/v); reaction for 24 h at , 408C.
ꢃ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemSusChem 2013, 6, 826 – 830 828

CHEMSUSCHEM
FULL PAPERS
www.chemsuschem.org
hyde 5 were detected. Because the concentration of H O was
afford 2,5-diformylfuran, a further lipase-mediated peracid-as-
sisted oxidation led to 2,5-furandicarboxylic acid (a promising
building block) in high yields and selectivities, even at high
substrate loadings. Overall, results reported herein present
a new peracid-based route for the oxidative valorization of bio-
mass-derived furanics, which may bring innovative approaches
in the field once optimization and process-development con-
siderations are taken into account.
2
2
the same in all experiments (400 mm in total), a plausible
reason for the lower conversion at higher substrate loadings
may be an insufficient amount of oxidant.
Remarkably, the organocatalytic–enzymatic approach pro-
vides a new entry for the synthesis of 6, which is a promising
[
1]
building block. Envisaging further steps in this area for
a more sustainable chemical process, a combined one-pot
two-step TEMPO–lipase approach was preliminarily assessed
(Table 2).
Acknowledgements
This work was performed as part of the Cluster of Excellence
Table 2. Proof-of-concept of an integrated TEMPO–lipase one-pot two-
step approach for the synthesis of 6 from HMF using 4 as substrate,
either commercial or formed through the TEMPO pathway. Conditions for
the enzymatic process are analogous to that of Figure 3 (with a concentra-
tion of 50 mm for 4).
“Tailor-Made Fuels from Biomass”, which is funded by the Excel-
lence Initiative of the German Research Foundation to promote
science and research at German universities. Furthermore, finan-
cial support from the DFG training group 1166 BioNoCo (“Bio-
catalysis in Non-Conventional Media”) is gratefully acknowl-
edged. We are grateful to Dr. Harald Dibowski of Dichrom GmbH
Origin of substrate 4
Yield [%]
5
6
(
formerly SeQuant GmbH)–Silicycle Inc. for donating a sample of
commercial, solid
0
100
93
48
isolated (TEMPO), purified, solid
non-isolated (TEMPO), dissolved
non-isolated (TEMPO), washed
7
52
17
the silica-immobilized TEMPO, and to c-LEcta GmbH for the pro-
vision of the Immo-CAL-B.
83
Keywords: biocatalysis · enzymes · oxidation · supported
catalysts · synthetic methods
The integration of the organocatalytic TEMPO-based oxida-
tion in ethyl acetate may be compatible with a further lipase-
mediated oxidation of 4. When a workup step was included
between the two reactions high yields were achieved, thus
showing that a reaction based on the isolated product formed
through the organocatalytic route proceeded as well as that
which involved the use of commercial 4. When the EtOAc
phase of the TEMPO reaction was directly separated from the
aqueous solution (NaOCl, KBr) and directly applied into the
next CAL-B-based approach, full conversion of 4 was observed,
albeit at the cost of forming only 52% of intermediate 5 and
[
1] a) G. Rødsrud, M. Lersch, A. Sjçde, Biomass Bioenergy 2012, 46, 46–59;
b) P. Domꢀnguez de Marꢀa, ChemSusChem 2011, 4, 327–329; c) Biorefi-
neries—Industrial processes and products. Status quo and future direc-
tions (Eds.: B. Kamm, P. R. Gruber, M. Kamm), Wiley-VCH, Weinheim,
2
010; d) J. P. Lange, Biofuels Bioprod. Biorefin. 2007, 1, 39–48.
[
2] Recent reviews on furfural: a) J. P. Lange, E. van der Heide, J. van Buijte-
nen, R. Price, ChemSusChem 2012, 5, 150–166; b) S. Dutta, S. De, B.
Saha, M. I. Alam, Catal. Sci. Technol. 2012, 2, 2025–2036.
[3] Recent reviews on HMF: a) R. J. van Putten, J. C. van der Waal, E.
de Jong, C. B. Rasrendra, H. J. Heeres, J. G. de Vries, Chem. Rev. 2013,
113, 1499–1597; b) S. Lima, M. M. Antunes, M. Pillinger, A. A. Valente,
ChemCatChem 2011, 3, 1686–1706; c) A. A. Rosatella, S. P. Simeonov,
R. F. M. Frade, C. A. M. Afonso, Green Chem. 2011, 13, 754–793; d) M. E.
Zakrzewska, E. Bogel-Lukasik, R. Bogel-Lukasik, Chem. Rev. 2011, 111,
48% of 6; the low selectivity towards 6 might be due to the
existence of impurities resulting from the TEMPO reaction.
By looking from a different perspective (not solely focusing on
397–417; e) X. Tong, Y. Ma, Y. Li, Appl. Catal. A 2010, 385, 1–13.
[
4] Recent examples: a) P. M. Grande, C. Bergs, P. Domꢀnguez de Marꢀa,
ChemSusChem 2012, 5, 1203–1206; b) T. vom Stein, P. M. Grande, W.
Leitner, P. Domꢀnguez de Marꢀa, ChemSusChem 2011, 4, 1592–1594;
c) L. Lai, Y. Zhang, ChemSusChem 2011, 4, 1745–1748; d) R. Huang, W.
Qi, R. Su, Z. He, Chem. Commun. 2010, 46, 1115–1117; e) B. Kim, J.
Jeong, S. Shin, D. Lee, S. Kim, H. J. Yoon, J. K. Cho, ChemSusChem 2010,
6
) that option might provide new leads to produce 5 selective-
ly. Remarkably, when the EtOAc–TEMPO phase was washed
twice with water before implementing it in subsequent enzy-
matic reactions, improved yields of 83% in 6 were achieved
(Table 2). Overall, this proof of concept demonstrates that
3, 1273–1275; f) S. Hu, Z. Zhang, Y. Zhou, J. Song, H. Fan, B. Han, Green
a one-pot two-step process for the production of 6 starting
from HMF may be feasible, once pertinent optimizations are
carried out.
Chem. 2009, 11, 873–877; g) A. Takagaki, M. Ohara, S. Nishimura, K. Ebi-
tani, Chem. Commun. 2009, 6276–6278; h) F. Ilgen, D. Ott, D. Kralisch,
C. Reil, A. Palmberger, B. Kçnig, Green Chem. 2009, 11, 1948–1954.
5] a) D. Chakraborty, C. Majumder, P. Malik, Appl. Organomet. Chem. 2011,
[
2
5, 487–490; b) V. Nair, V. Varghese, R. R. Paul, A. Jose, C. R. Sinu, R. S.
Menon, Org. Lett. 2010, 12, 2653–2655; c) D. Chakraborty, R. R. Gowda,
P. Malik, Tetrahedron Lett. 2009, 50, 6553–6556; d) S. Mannam, G. Sekar,
Tetrahedron Lett. 2008, 49, 1083–1086; e) P. Verdeguer, N. Merat, L.
Rigal, A. Gaset, J. Chem. Technol. Biotechnol. 1994, 61, 97–102.
6] a) S. E. Davis, B. N. Zope, R. J. Davis, Green Chem. 2012, 14, 143–147;
b) N. K. Gupta, S. Nishimura, A. Takagaki, K. Ebitani, Green Chem. 2011,
13, 824–827; c) O. Casanova, S. Iborra, A. Corma, ChemSusChem 2009,
Conclusions
Herein, we successfully explored the use of lipases as biocata-
lysts for the in situ production of organic peracids, which may
subsequently perform the selective oxidation of biomass-de-
rived furanics and finally afford a range of useful building
blocks. Under mild and non-optimized conditions, furfural
could be readily oxidized to furoic acid, whereas HMF yielded
its acidic alcohol derivative with excellent selectivities and
yields. Upon TEMPO-catalyzed oxidation of HMF to selectively
[
2, 1138–1144; d) T. Reichstein, Helv. Chim. Acta 1926, 9, 1066–1068.
[
7] a) H. J. Yoon, J. W. Choi, H. S. Jang, J. Cho, J. W. Byun, W. J. Chung, S. M.
Lee, Y. S. Lee, Synth. Lett. 2011, 2, 165–168; b) J. Ma, Z. Du, J. Xu, Q.
Chu, Y. Pang, ChemSusChem 2011, 4, 51–54; c) H. Mehdi, A. Bodor, D.
Lantos, L. T. Horvꢂth, D. E. de Vos, K. Binnemans, J. Org. Chem. 2007, 72,
ꢃ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemSusChem 2013, 6, 826 – 830 829

CHEMSUSCHEM
FULL PAPERS
www.chemsuschem.org
5
2
2
17–524; d) C. Carlini, P. Patrono, G. Sbrana, V. Zima, Appl. Catal. A
005, 289, 197–204; e) W. Partenheimer, V. V. Grushin, Adv. Synth. Catal.
001, 343, 102–111; f) L. Cottier, G. Descotes, J. Lewkowski, R. Skoronski,
J. Schilling, U. Tschirner, W. W. AlDajani, Appl. Biochem. Biotechnol. 2010,
160, 1637–1652.
[16] CAL-B is not able to accept tertiary alcohols as nucleophiles. See: R.
Kourist, P. Domꢀnguez de Marꢀa, U. T. Bornscheuer, ChemBioChem 2008,
9, 491–498.
[17] a) S. Bhattacharya, A. Drews, E. Lyagin, M. Kraume, M. B. Ansorge-
Schumacher, Chem. Eng. Technol. 2012, 35, 1448–1455; b) R. Nieguth,
M. Eckstein, L. Wiemann, O. Thum, M. B. Ansorge-Schumacher, Adv.
Synth. Catal. 2011, 353, 2522–2528; c) C. Z. Wu, M. Kraume, M. B. An-
sorge-Schumacher, ChemCatChem 2011, 3, 1314–1319.
E. Viollet, J. Heterocycl. Chem. 1995, 32, 927–930.
[
8] a) A. Sanborn, US20120059178, 2012; b) Z. W. Mei, L. J. Ma, H. Kawafu-
chi, T. Okihara, T. Inokuchi, Bull. Chem. Soc. Jpn. 2009, 82, 1000–1002.
9] a) G. Borsotti, F. Digioia, WO2012/017052, 2012; b) M. L. Ribeiro, U.
Schuchardt, Catal. Commun. 2003, 4, 83–86; c) M. Krçger, U. Prꢅße,
K. D. Vorlop, Top. Catal. 2000, 13, 237–242; d) B. W. Lew, US3326944,
[
1
968.
[
10] H. I. Pꢁrez, N. Manjarrez, A. Solꢀs, H. Luna, M. A. Ramꢀrez, J. Cassani, Afri-
can J. Biotechnol. 2009, 8, 2279–2282.
11] a) H. J. Ruijssenaars, N. J. P. Wierckx, F. W. Koopman, CA277503, 2011;
b) F. W. Koopman, N. J. P. Wierckx, J. H. de Winde, H. J. Ruijssenaars, Bio-
resour. Technol. 2010, 101, 6291–6296.
[18] a) K. Hernꢂndez, A. Berenguer-Murcia, R. C. Rodrigues, R. Fernꢂndez-
Lafuente, Curr. Org. Chem. 2012, 16, 2652–2672; b) K. Hernꢂndez, R.
Fernꢂndez-Lafuente, Process Biochem. 2011, 46, 873–878.
[
[
19] For further synthetic purposes, the use of 5-hydroxymethylfuroic acid
3) or its ester form results in the same substrate. For HMF esterifica-
(
tions with lipases see: M. Krystof, M. Pꢁrez-Sꢂnchez, P. Domꢀnguez de
Marꢀa, ChemSusChem 2013, 4, 630–634.
20] O. L. Lebedev, S. N. Kazarnovskii, Zhur. Obshch. Khim. 1960, 30, 1631–
[
12] a) P. D. Hanke, US8183020, 2012; b) M. P. van Deurzen, F. van Rantwijk,
R. A. Sheldon, J. Carbohydr. Chem. 1997, 16, 299–309.
[
[
[
13] R. Brꢅckner, Reaktionsmechanismen, Springer, Berlin, 2007.
14] a) D. Gamenara, G. Seoane, P. Saꢁnz Mendez, P. Domꢀnguez de Marꢀa,
Redox Biocatalysis: Fundamentals and applications, Wiley, Hoboken, NJ,
1635.
[
21] a) L. Tebben, A. Studer, Angew. Chem. 2011, 123, 5138–5174; Angew.
Chem. Int. Ed. 2011, 50, 5034–5068; b) P. L. Anelli, C. Biffi, F. Montanari,
S. Quici, J. Org. Chem. 1987, 52, 2559–2562.
22] Commercially available by Silicycle Inc. under the name of SiliaCAT
TEMPO.
2
012; b) C. Carboni-Oerlemans, P. Domꢀnguez de Marꢀa, B. Tuin, G.
Bargeman, A. van der Meer, R. W. van Gemert, J. Biotechnol. 2006, 126,
40–151.
[
1
[
15] a) L. Wiermans, M. Pꢁrez-Sꢂnchez, P. Domꢀnguez de Marꢀa, Chem-
SusChem 2013, 6, 251–255; b) D. T. Yin, Q. Jing, W. W. AlDajani, S.
Duncan, U. Tschirner, J. Schilling, R. J. Kazlauskas, Bioresour. Technol.
Received: December 13, 2012
2011, 102, 5183–5192; c) S. Duncan, Q. Jing, A. Katona, R. J. Kazlauskas,
Published online on April 10, 2013
ꢃ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemSusChem 2013, 6, 826 – 830 830