A Cptt-Based Trioxo-Rhenium Catalyst for the Deoxydehydration of Diols and Polyols

Article abstract of DOI:10.1002/cctc.201801151

Trioxo-rhenium complexes are well known catalysts for the deoxydehydration (DODH) of vicinal diols (glycols). In this work, we report on the DODH of diols and biomass-derived polyols using Cp^ttReO₃ as a new catalyst (Cp^tt=1,3-di-tert-butylcyclopentadienyl). The DODH reaction was optimized using 2 mol % of Cp^ttReO₃ and 3-octanol as both reductant and solvent. The Cp^ttReO₃ catalyst exhibits an excellent activity for biomass-derived polyols. Specifically, glycerol is almost quantitatively converted to allyl alcohol and mucic acid gives 75 % of muconates at 91 % conversion. In addition, the loading of Cp^ttReO₃ can be reduced to 0.1 mol % to achieve a turn-over number as high as 900 per Re when using glycerol as substrate. Examination of DODH reaction profiles by NMR spectroscopy indicates that catalysis is related to Cp-ligand release, which raises questions on the nature of the actual catalyst.

Full text of DOI:10.1002/cctc.201801151

Accepted Article
Title: A Cptt-based Trioxo-Rhenium Catalyst for the Deoxydehydration
of Diols and Polyols
Authors: Jing Li, Martin Lutz, Matthias Otte, and Robertus Johannes
Klein Gebbink
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: ChemCatChem 10.1002/cctc.201801151
Link to VoR: http://dx.doi.org/10.1002/cctc.201801151
A Journal of
www.chemcatchem.org

10.1002/cctc.201801151
ChemCatChem
FULL PAPER
A Cptt-based Trioxo-Rhenium Catalyst for the Deoxydehydration
of Diols and Polyols
Jing Li [a], Dr. Martin Lutz [b], Dr. Matthias Otte [a,c], and Prof. Dr. Robertus J. M. Klein Gebbink *[a]
Abstract: Trioxo-rhenium complexes are well known catalysts for
the deoxydehydration (DODH) of vicinal diols (glycols). In this work,
we report on the DODH of diols and biomass-derived polyols using
CpttReO3 as a new catalyst (Cptt = 1,3-di-tert-butylcyclopentadienyl).
The DODH reaction was optimized using 2 mol% of CpttReO3 and 3-
octanol as both reductant and solvent. The CpttReO3 catalyst
= hydrido-tris-(3,5-dimethylpyrazolyl)borate), and in doing so
used the 6e– Tp* ligand as an alternative for the 6e– Cp*
ligand.[15] Recently, we reported on a bulky Cp-based trioxo-
rhenium
catalyst,
CptttReO3
(Cpttt
=
1,2,4-tri-tert-
butylcyclopentadienyl, Scheme 1, middle).[16] This trioxo-rhenium
complex is able to effectively catalyze the DODH of a series of
exhibits an excellent activity for biomass-derived polyols. Specifically, different diols and polyols. The electron-rich Cpttt ligand of the
glycerol is almost quantitatively converted to allyl alcohol and mucic
acid gives 75% of muconates at 91% conversion. In addition, the
loading of CpttReO3 can be reduced to 0.1 mol% to achieve a turn-
complex stabilizes the high-valent rhenium center, avoiding
over-reduction, and hampers catalyst dimerization leading to
decomposition, to result in high TONs. Interestingly, a slight
over number as high as 900 per Re when using glycerol as substrate. change of the ligand (removing one tert-butyl group) resulted in
Examination of DODH reaction profiles by NMR spectroscopy
indicates that catalysis is related to Cp-ligand release, which raises
questions on the nature of the actual catalyst.
a different DODH reactivity of the trioxo-rhenium complex.[17] We
observed an induction period in the CptttReO3-catalyzed DODH
of 1,2-octanediol, while there was almost no induction period in
the reaction catalyzed by the CpttReO3 complex (Cptt = 1,3-di-
tert-butylcyclopentadienyl, Scheme 1, right). This result
encouraged us to further investigate the catalytic properties of
the less bulky CpttReO3 complex. Here, we report on the DODH
of diols and biomass-derived polyols using CpttReO3.
Introduction
Due to the anticipated depletion of fossil feedstocks, the search
for alternative and renewable chemical feedstocks receives a lot
of attention.[1,2] Biomass is such a potential resource for the
sustainable production of commodity chemicals and other
chemical building blocks.[3–5] Biomass-derived feedstocks, such
as sugars and polyols, are highly oxygenated, mostly in the form
of hydroxyl groups. In order to make use of these feedstocks,
(partial) deoxygenation is required. Deoxydehydration (DODH)
reactions,[6–8]
which
constitute
a
combination
of
deoxygenation[9,10] and dehydration,[11] can efficiently convert
vicinal diols and polyols into olefins.[12–14]
Scheme 1. Cp-base trioxo-Rhenium catalysts.
Trioxo-rhenium complexes are known as active catalysts for
DODH reactions since the first catalytic DODH reaction was
described by Cook and Andrews.[12] In this very early work, a
Cp*ReO3 complex (Scheme 1, left) was used to catalytically
convert polyols into olefins. Later, Gable and coworkers studied
olefin extrusion reactions from Tp*Re(glycolate) complexes (Tp*
Results and Discussion
We started our investigation on the use of CpttReO3 as a catalyst
for the DODH of vicinal diols into olefins by using 1,2-octanediol
as a substrate (Table 1). Initial reactions were performed with 2
o
mol% CpttReO3 at 135 C in chlorobenzene and 1.1 equivalent
of sacrificial reducing agent under an inert nitrogen atmosphere.
The use of triphenylphosphine (PPh3) as reducing agent gave
an excellent yield at full conversion (entry 1), which matched the
data reported in our previous study.[17] Sodium sulfite and active
carbon gave a very poor conversion, probably because of their
poor solubility in the chlorobenzene reaction medium (entry 2
and 3). The use of molecular hydrogen (40 bar) resulted in only
1.2 % n-octane as the over-reduced product at 23% substrate
conversion (entry 4).
[a]
J. Li, Dr. M. Otte, Prof. Dr. R. J. M. Klein Gebbink
Organic Chemistry and Catalysis
Debye Institute for Nanomaterials Science
Utrecht University
Universiteitsweg 99, 3584CG, Utrecht (The Netherlands)
E-mail: R.J.M.KleinGebbink@uu.nl
Dr. Martin Lutz
Crystal and Structural Chemistry
Bijvoet Center for Biomolecular Research
Faculty of Science, Utrecht University
Padualaan 8, 3584 CH, Utrecht (The Netherlands)
current address:
[b]
[c]
Secondary alcohols have been reported as both reductants and
solvents for Re-catalyzed DODH reactions.[18] Using 3-octanol
as reductant, a 93% yield of 1-octene was achieved when the
Institut für Anorganische Chemie
University of Göttingen,
Tammannstraße 4, 37077, Göttingen (Germany)
o
reaction was carried out at 135 C for 15 h (entry 5). Increasing
the reaction temperature to 170 oC lead to a decreased 1-octene
yield at complete conversion (entry 6). Besides, even under
aerobic conditions, i.e. carrying the reaction out in air, 68% of 1-
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/cctc.201801151
ChemCatChem
FULL PAPER
octene was formed at 76% conversion using CpttReO3 as
catalyst and 3-octanol as reductant (entry 7). In our previous
studies on the more bulky CptttReO3 catalyst, we also observed
that aerobic reaction conditions would decrease the activity of
the catalyst.[19] Both PPh3 and 3-octanol gave high yield,
considering the solvent chlorobenzene was neither green nor
good at dissolving biomass-derivatives, 3-octanol was chosen
as the reducing agent in subsequent DODH reactions with
CpttReO3.
fermentation,[23] was converted to 1,3-butadiene (69%) with 2,5-
dihydrofuran (5%) as by-product under optimized reaction
conditions (entry 7). Another C4 sugar alcohol, DL-threitol, gave
71% of 1,3-butadiene with 13% of 1,4-anhydroethreitol as by-
product (entry 8). With these two reactions, 1,3-butadiene, an
industrially important building block, can be formed from
sustainable starting materials. Interestingly, for these two
reactions, increasing the temperature from 135 oC to 170 oC and
decreasing the reaction time from 15 h to 1.5 h lead to an
increased 1,3-butadiene yield of 87 and 90%, respectively (entry
9 and 10). We also observed that even under aerobic conditions
erythritol gave 57% of 1,3-butadiene at 87% conversion with 4%
of 2,5-dihydrofuran as by-product (entry 11). For the CptttReO3-
catalyzed DODH of erythritol and DL-threitol, 1,3-butadiene was
formed at a lower 67 and 59% yield, respectively, under N2 at
170 oC.
Table 1. Optimization of reaction conditions and sacrificial reducing agent
in the DODH of 1,2-octanediol to 1-octene catalyzed by CpttReO3.[a]
entry
1[b]
2[b]
3[b]
4[b]
5[c]
reductant
PPh3
conditions
yield
93%
N.D.
N.D.
1.2% [e]
93%
81%
68%
conversion
> 99%
6%
135 oC, 15 h, N2
135 oC, 15 h, N2
135 oC, 16 h, N2
135 oC, 16 h, N2
135 oC, 15 h, N2
170 oC, 2 h, N2
135 oC, 15 h, air
Na2SO3
C
Table 2. DODH of vicinal diols and polyols to olefins catalyzed by
40%
CpttReO3.[a]
d
【
】
H2
23%
entry
1
substrate
product
C6H13
O
yield[b]
93%
conversion
> 99%
3-octanol
3-octanol
3-octanol
> 99%
> 99%
76%
OH
6[c]
C6H13
OH
7[c]
O
2
3
83%
76%
> 99%
> 99%
HO
[a] Reaction conditions: 1,2-octanediol (0.5 mmol), CpttReO3 (0.01 mmol, 2
mol%), reductant (0.55 mmol, 1.1 equivalent). [b] PhCl (0.5 mL) was used
as solvent, the yield and conversion were determined by gas
chromatography using mesitylene (0.5 mmol) as an internal standard. [c] 3-
octanol (0.5 mL) was used as both reductant and solvent, the yield and
conversion were determined by 1H NMR using mesitylene (0.5 mmol) as
an internal standard. [d] Pressure of H2: 40 bar. [e] Yield of n-octane.
OH
OH
OH
OH
4[c]
OH
90%
95%
99%
> 99%
> 99%
Following these optimization studies, the substrate scope using
a variety of vicinal diols and biomass-derived polyols was
investigated under optimized reaction conditions (Table 2). 1,4-
anhydroerythritol gave 83% of 2,5-dihydrofuran (entry 2). The
aromatic vicinal diol 1-phenyl-1,2-ethanediol gave 76% yield of
styrene at full conversion (entry 3), while (R,R)-1,2-diphenyl-1,2-
ethanediol selectively gave trans-stilbene in 95% yield (entry 5).
Interestingly, we observed a higher yield (90%) of styrene when
PPh3 was used as reductant (entry 4). The lower yield of styrene
could be explained by ketal formation from the diol substrate and
3-octanone (dehydrogenation product of 3-octanol) during the
reaction. A 99% styrene yield was realized with the CptttReO3
catalyst while PPh3 was used as reductant.[16] Overall though,
the conversions and yields that can be achieved in DODH
reactions of vicinal diols with the less bulky CpttReO3 catalyst
are quite similar to those with the CptttReO3 catalyst.
5
OH
OH
OH
OH
6
7
> 99%
93%
HO
OH
HO
HO
OH
OH
69%
(74%)[f]
HO
HO
OH
OH
71%
8
93%
(84%)[g]
HO
HO
OH
OH
9[d]
> 99%
87%
(94%)[f]
When CpttReO3 was applied to DODH reactions of biomass-
derived polyols it was found to have a much better product
selectivity than the previously reported CptttReO3 catalyst.
Glycerol is the by-product formed during the transesterification
of vegetable oils for the production of biodiesel.[20,21] Under our
optimized reaction conditions, glycerol was almost quantitatively
HO
HO
OH
OH
10[d]
11[e]
> 99%
87%
90%
(95%)[g]
HO
HO
OH
OH
57%
(61%)[f]
converted to allyl alcohol (entry 6), which is
a versatile
[a] Reaction conditions: substrates (0.5 mmol), CpttReO3 (0.01 mmol, 2
mol%), 3-octanol (0.5 mL, 0.1 M), N2, 135 oC, 15 h. [b] Determined by 1H
NMR using mesitylene (0.5 mmol) as an internal standard. [c] Reaction
conditions: substrates (0.5 mmol), CpttReO3 (0.01 mmol, 2 mol%), PPh3
(0.55 mmol, 1.1 equiv), PhCl (0.5 mL, 0.1 M), N2, 135 oC, 15 h. [d]170 oC,
1.5 h, N2. [e] air. [f] Total yield of 1,3-butadiene and 2,5-dihydrofuran. [g]
intermediate for various useful chemicals such as agrochemicals,
resins, medicines, perfumes, and so on.[22] When our previous
CptttReO3 was used as catalyst for the deoxydehydration of
glycerol, 91% of allyl alcohol was obtained at full conversion.[16]
Erythritol, which can be produced from glucose by
This article is protected by copyright. All rights reserved.

10.1002/cctc.201801151
ChemCatChem
FULL PAPER
OH OH
Total yield of 1,3-butadiene and 1,4-anhydroethreitol.
CpttReO3 2 mol%
OH
HO
3-octanol (0.1 M)
135 oC, 15 h, N2
For the very useful deoxydehydration of glycerol, we planned to
investigate this reaction with different CpttReO3 loadings and
using different alcohols as sacrificial reductant. Considering
there would be a competition between deoxydehydration of
glycerol and dehydration of the alcohol, since rhenium
complexes can also catalyse the dehydration of secondary
alcohols,[8] we started the investigation with testing different
alcohols to find the most suitable reductant (see Supporting
information). Finally, 2,4-dimethyl-3-pentanol, which is difficult to
be dehydrated, was chosen as the reductant for this experiment.
Then different loadings of CpttReO3 were tested and the loading
could be lowered to 0.1 mol% (see Supporting information).
Using this catalyst loading glycerol could be converted to allyl
alcohol at 90% yield with a total turn-over number per Re of 900
(Scheme 2). To our knowledge, this is the highest TON reported
for a homogeneous Re-catalyst in the DODH of glycerol.
OH OH
OH OH
OH OH
OH
OH
HO
HO
OH OH
OH OH
D-mannitol
35% yield
D-sorbitol
17% yield
Scheme 4. CpttReO3-catalyzed DODH of C6 sugar alcohols.
Adipic acid, a building block for the large-volume production of
nylon-6,6 polyamide,[24] is mainly produced from non-renewable
petroleum-based cyclohexane. The production procedures
include a nitric acid oxidation process, which emits large
amounts of nitrous oxides.[25] An alternative way to produce
adipic acid is using sustainable mucic acid to form muconates
through DODH chemistry, followed by hydrogenation and
hydrolysis.[26] Accordingly, we have investigated the activity of
the CpttReO3 catalyst in the DODH of mucic acid. Under
modified reaction conditions, mucic acid gave 75% of
isopentylmuconate at 91% conversion after 12 h using 3-
CpttReO3 0.1 mol%
135 oC, N2, 300 h
OH
OH
+
H2O
HO
OH
yield: 90 %
TON: 900
o
pentanol as reducing agent at 120 C. Under the same reaction
conditions, when our previous CptttReO3 catalyst was uses as
catalyst only 28% of muconates were formed at 48% conversion
(Scheme 4), and when MTO was used as catalyst 71% of
muconates were formed at 98% conversion.[26]
O
OH
Scheme 2. CpttReO3-catalyzed DODH of glycerol.
Encouraged by the results of CpttReO3-catalyzed DODH
reactions of glycerol and C4 sugar alcohols, we then tested the
C5 sugar alcohols xylitol, D-arabinitol, and adonitol (Scheme 3).
Instead of (E)-2,4-pentadienol, (E)-5-penta-1,3-diene ether was
formed in this reaction, as was earlier noted by Toste and
coworkers.[13] Under our reaction conditions, xylitol, D-arabinitol,
and adonitol formed the (E)-5-penta-1,3-diene ethers at a yield
of 46%, 48%, and 42%, respectively. Interestingly, when
methyltrioxorhenium (MTO) was used as catalyst for these
reactions under more harsh reaction conditions, xylitol gave
much more product (61%) than adonitol (33%).[13] Next to the
reactions on C5 sugar alcohols, we also carried out reactions on
two C6 sugar alcohols (Scheme 4). D-mannitol gave approx.
35% yield of 1,3,5-hexatriene, while D-sorbitol only gave 17%
yield of 1,3,5-hexatriene (see supporting information).
O
OH OH
O
HOOC
O
O
[Re] 5 mol%
HO
OH
O
3-pentanol (0.1 M)
120 oC, 12 h, N2
O
OH OH
O
O
[Re] = CpttReO3, yield: 75 %, conversion: 91%
[Re] = CptttReO3, yield: 28 %, conversion: 48%
Scheme 5. CpttReO3-catalyzed DODH of mucic acid.
Finally, we have also applied the CpttReO3 catalyst to DODH
reactions of a number of sugar compounds, 2-Vinylfuran (2-VF)
and furan were formed as the main products, which is in line
with the observations of Toste.[13] Under our optimized reaction
o
conditions, using 3-octanol as the reducing agent at 135 C for
OH
15 h, 2-vinylfuran was the main product albeit at low yield
(entries 1-3). An interesting observation was that when using 3-
pentanol as reductant and solvent, the reaction mixture was
more homogenous than when using 3-octanol. 3-pentanol was
then chosen as the reductant and solvent for the DODH of sugar
compounds. For the three sugars we have tested, D-glucose
gave a very poor yield (entry 1, 4, 7), while D-mannose gave the
highest yield up to 39% (entry 9). Besides, in terms of product
selectivity, the reaction of D-galactose is quite sensitive to the
reaction conditions; the ratio of 2-VF and furan products
changes when using a different reductant (entry 2, 5, 8). D-
galactose selectively forms furan as the only product when 3-
pentanol was used as reductant (entry 8). For D-mannose, a
different reductant does not have an obvious effect on product
selectivity (entry 3, 6, 9), although consistently giving the highest
product yields amongst the three sugar substrates.
CpttReO3 2 mol%
O
HO
HO
OH
OH
3-octanol (0.1 M)
135 oC, 15 h, N2
OH OH
OH
OH
OH
HO
OH
HO
OH
OH OH
OH OH
OH OH
xylitol
46% yield
D-arabinitol
48% yield
adonitol
42% yield
Scheme 3. CpttReO3-catalyzed DODH of C5 sugar alcohols.
This article is protected by copyright. All rights reserved.

10.1002/cctc.201801151
ChemCatChem
FULL PAPER
In the experiment using CpttReO3, peaks in the vinylic and the
allylic region, e.g. between 6.30,- 5.70 and 2.85, - 2.70 ppm,
started to appear from the very start of the experiment (see
Supporting Information). These peaks could be assigned to free
CpttH ligand. The observation of free ligand during catalysis was
interpreted to originate from ligand dissociation. In a similar
manner, ligand dissociation was also observed in the experiment
using CptttReO3, albeit at a slower rate than for CpttReO3. In the
former case, 60% of ligand dissociation occurred after 5 min,
during which 8% of 1-octene was formed. After 30 min,
maximum ligand dissociation (94%) was reached, and the
DODH reaction finished after 50 min at 88 % 1-octene yield
(Scheme 6, top). When CptttReO3 was used as catalyst,
maximum ligand dissociation (27%) was reached at 80 min, and
the DODH reaction finished after 150 min at 93% product yield
(Scheme 6, middle). In this case, NMR signals related to typical
Cp’Re-based reaction intermediates like Cp’Re-glycolates were
also observed (see Supporting Information).[27]
Table 3. DODH of sugars to 2-vinylfuran (2-VF) and furan catalyzed by
CpttReO3.[a]
entry
sugar
conditions
yield[b]
8%
ratio (2-VF :furan)
1.7:1
1.2：1
2.5：1
--
1
D-glucose
D-galactose
D-mannose
D-glucose
D-galactose
D-mannose
D-glucose
D-galactose
D-mannose
3-octanol,135oC, 15 h
3-octanol,135oC, 15 h
3-octanol,135oC, 15 h
3-pentanol, 135 oC, 15 h
3-pentanol, 135 oC, 15 h
3-pentanol, 135 oC, 15 h
3-pentanol, 155 oC, 12 h
3-pentanol, 155 oC, 12 h
3-pentanol, 155 oC, 12 h
2
22%
21%
trace
13%
26%
trace
14%
39%
3
4
5
1:1.6
2.3:1
--
6
7
8[c]
9
--
The time course profile of the olefin generation matches our
previous results, i.e. there is no clear induction period for the
CpttReO3-catalyzed DODH reaction, while there is an obvious
induction period for the CptttReO3-catalyzed reaction. In addition,
initial olefin product formation is related to the rate of ligand
dissociation, while the final amount of product is not related to
the extent of overall ligand dissociation.
2.3:1
[a] Reaction conditions: sugars (0.5 mmol), CpttReO3 (0.01 mmol, 2 mol%),
N2. [b] Total yield of 2-VF and furan, determined by 1H NMR using
mesitylene (0.5 mmol) as an internal standard. [c] No 2-VF formation.
The above results show that the less bulky CpttReO3 complex
catalyzes the DODH of both aromatic and aliphatic vicinal diols
with high yield and product selectivity. Extending the substrate
scope to bio-based polyols, the high yield and product selectivity
for this catalyst remains. Specifically, glycerol is almost
quantitatively converted to allyl alcohol and mucic acid gives
75% of muconates at 91% conversion. Besides, even for more
complicated sugar alcohols and sugars, the DODH reaction can
be realized at moderate yields. Based on these data, we
compared the CpttReO3 catalyst with our previous generation
catalyst CptttReO3 for which the advantageous performance in
DODH catalysis was attributed to its overall steric bulk provide
by the Cpttt ligand. Both catalysts show a high DODH reactivity
and selectivity for general vicinal diols, while in particular for bio-
based polyols CpttReO3 shows a significantly improved reactivity
and product selectivity. This comparison challenges the initial
hypothesis that DODH catalysis improves with ligand bulk for
Cp’ReO3 type catalysts.
The observation of ligand dissociation raises questions on the
nature of the active species in Cp’ReO3-catalyzed DODH
reactions. We have therefore also examined ligand dissociation
for some other molecular Cp’Re complexes under catalytic
conditions using the NMR protocol. The tetranuclear Re-
complex Cptt Re2O3(ReO4)2, which is formed by stirring CpttReO3
2
in dichloromethane overnight at room temperature, was earlier
reported to catalyze the DODH reaction.[17] Also for this complex,
free CpttH ligand was detected during the reaction. Interestingly,
ligand dissociation was even faster than for CpttReO3; 88% of
ligand dissociation occurred after 10 min and the DODH reaction
was finished in about 50 min at 90% product yield and without a
significant induction period (Scheme 6, bottom). Re(V)-diolate
species have been reported as intermediates in DODH reactions
from which olefin extrusion takes place to form Re(VII) trioxo
species to close the catalytic cycle.[8] The Cp’ReO(OCH2CH2O)
complexes (Cp’ = Cptt, Cpttt) were synthesized on the basis of a
reported procedure.[28] Investigation of these glycolate
complexes using the same NMR experiment showed that these
have similar DODH reaction and ligand dissociation profiles as
the corresponding trioxo-Re species (see Supporting
information). When CpttReO(OCH2CH2O) was used as catalyst,
the signals of CpttReO(OCH2CH2O) disappeared almost at the
beginning of the reaction. When CptttReO(OCH2CH2O) was used
as catalyst, it was slowly converted in around 30 min, and next
to olefin product formation concomitant formation of CptttReO-
octanediolate was also observed.
In our previous work, we found a difference in the kinetic profile
of the DODH reaction of 1,2-octanediol when either CptttReO3 or
CpttReO3 was used as catalyst. [17] A clear induction period was
observed for the CptttReO3-catalyzed DODH reaction, while
there was almost no induction period for the CpttReO3-catalyzed
reaction. This observation was a further indication that the Cp-
ligand structure has an effect on DODH catalysis, not only in
terms of activity and selectivity, but also in terms of kinetics and
catalyst evolution.
Since ligand dissociation was observed for all Cp’Re complexes
tested above, one could hypothesize that the actual active
species in these systems does not contain a Cp’ ligand. The
same catalytic NMR-experiment was therefore carried out using
a perrhenate devoid of a Cp’-ligand as catalyst, i.e. Bu4NReO4.
In this case, no olefin product formation could be detected at all.
For perrhenate-catalyzed DODH of aliphatic diols,[29-35] either a
long reaction time (> 24 h) or a high catalyst loading (10 mol%)
is needed in order to reach full conversion. Besides, even in the
In order to further investigate catalyst evolution under catalytic
conditions, the catalytic DODH of 1,2-octanediol by a number of
Cp’Re complexes was examined using in situ NMR experiments.
Considering side reactions of secondary alcohols and possible
peak overlap, the following reaction conditions were chosen:
1,2-octanediol (0.05 mmol), PPh3 (0.055 mmol, 1.1 equiv.),
mesitylene (0.05 mmol, 1.0 equiv, internal standard), Re-catalyst
(10 mol% Re), toluene-D8 (0.5 mL), 135 oC, N2.
This article is protected by copyright. All rights reserved.

10.1002/cctc.201801151
ChemCatChem
FULL PAPER
case of full conversion of aliphatic diols and polyols, product
selectivity was not as high as for Cp’ReO3 systems. Especially,
for the DODH of glycerol, when lutidinium perrhenate was used
as catalyst, only moderate amounts (21%) of allyl alcohol were
formed,[33] while glycerol is almost quantitively converted to allyl
alcohol using CpttReO3. These data strongly indicate that
inorganic perrhenate is not the active species in Cp’ReO3-
catalyzed DODH reactions. We also compared our CpttReO3
catalyst with another homogenous trioxo-rhenium catalyst, MTO
(MeReO3).[13,14] For the DODH of simple diols, both of them
show good activity. For more complicated polyol substrates like
sugar alcohols and sugars, the two catalysts have a very
different product selectivity. This notion indicates that the active
species in the case of CpttReO3 and MTO are not the same.
Cptt2Re2O3(ReO4)2
100
90
80
70
60
50
40
30
20
10
0
octene yield %
free CpttH ligand %
0
10
20
30
40
50
60
time / min
Scheme 6. In situ NMR experiments of Cp’ReO3-catalyzed DODH of 1,2-
octanediol; monitoring of product yield and free Cp’ ligand formation (for
details see Supporting Information). Reaction conditions: 1,2-octanediol (0.05
mmol), PPh3 (0.055 mmol, 1.1 equiv.), mesitylene (0.05 mmol, 1.0 equiv,
internal standard), Re-catalyst (10 mol% Re), toluene-D8 (0.5 mL), 135 oC, N2.
CpttReO3 catalyzed DODH
100
90
80
70
60
50
40
Conclusions
octene yield %
30
20
10
0
In conclusion, we have shown efficient catalytic DODH reactions
of vicinal diols and biomass-derived polyols to olefins using the
new CpttReO3 catalyst. Secondary alcohols like 3-octanol and 3-
pentanol are the reductant and solvent of choice for these
reactions. Under optimized reaction conditions, CpttReO3 not
only initiates the catalytic conversion of vicinal diols into olefins
at high yields, but also exhibits an excellent activity for biomass-
derived polyols. Specifically, when using CpttReO3 as catalyst,
glycerol is almost quantitively converted to allyl alcohol and
mucic acid gives 75% of muconates at 91% conversion. Besides,
the loading of CpttReO3 can be reduced to 0.1 mol% to achieve
a turn-over number as high as 900 per Re in the DODH of
glycerol, indicating a rather stable active species. Time course
profile experiments have shown ligand dissociation during the
reaction with different dissociation rates for different substituted
Cp’ ligands. In addition, ligand dissociation seems to be related
to (initial) catalytic activity. These observations raise questions
on the nature of the active species in DODH catalysis, on the
role of the Cp’ ligand in catalysis, and in a more general sense
on the relation between the Cp’ ligand structure and the stability
of the corresponding Cp’ReO3 complexes. Comparison with
perrhenate salts seems to rule out a simple and purely inorganic
active species in DODH catalysis using Cp’ReO3 complexes.
Current investigations in our laboratories focus on further DODH
catalyst development and optimization, and on deciphering the
role of organometallic, ligand-based species and the nature of
active species in DODH catalysis.
free CpttH ligand %
0
10
20
30
40
50
60
time / min
CptttReO3 catalyzed DODH
100
90
80
70
60
50
40
30
20
10
0
octene yield %
free CptttH ligand %
0
30
60
90
120
150
time / min
Experimental Section
All chemicals including solvents were degassed by either freeze-pump-
thaw cycles or degasification under vacuum. Triphenylphosphine was
crystallized in ethanol and dried under vacuum. Unless otherwise stated,
all other commercial chemicals were used without further purification.
NMR spectra were recorded on a Varian VNMRS400 (400 MHz) at 298 K.
ESI-MS spectra were recorded using
a Waters LCT Premier XE
instrument. GC measurements were performed using a Perkin Elmer
This article is protected by copyright. All rights reserved.

10.1002/cctc.201801151
ChemCatChem
FULL PAPER
Autosystem XL Gas Chromatograph equipped with a Perkin Elmer Elite-
17 column (Length: 30m, I.D.: 0.32 mm, Film thickness: 0.50 µm), and
with FID detector. GC method: 40 °C, 5 min; 3 °C/min to 55 °C;
20 °C/min to 250 °C; 250 °C, 10 min. All olefinic products are known
compounds and were calibrated against mesitylene for quantification.
2016, 35, 2178-2187.
[18]
E. Arceo, J. A. Ellman, R. G. Bergman, J. Am. Chem. Soc. 2010,
132, 11408-11409.
[19]
[20]
S. Raju, PhD thesis, Utrecht University (the Netherlands), 2015.
C. H. Zhou, J. N. Beltramini, Y. X. Fan, G. Q. Lu, Chem. Soc. Rev.
2008, 37, 527-549.
[21]
M. Pagliaro, R. Ciriminna, H. Kimura, M. Rossi, C. Della Pina,
Angew. Chem. 2007, 119, 4516-4522; Angew. Chem. Int. Ed. 2007,
46, 4434-4440.
Acknowledgements
[22]
[23]
[24]
[25]
[26]
[27]
A. Konaka, T. Tago, T. Yoshikawa, A. Nakamura, T. Masuda, Appl.
Catal. B Environ. 2014, 146, 267-273.
JL acknowledges financial support through the Chinese
Scholarship Council. MO thanks Utrecht University for financial
support through their focal area on Sustainability. The X-ray
diffractometer has been financed by the Netherlands
Organization for Scientific Research (NWO).
E. S. Koh, T. H. Lee, D. Y. Lee, H. J. Kim, Y. W. Ryu, J. H. Seo,
Biotechnol. Lett. 2003, 25, 2103-2105.
S. Van De Vyver, Y. Román-Leshkov, S. Van de Vyver, Y. Román-
Leshkov, Catal. Sci. Technol. 2013, 3, 1465.
A. Alshammari, A. Koeckritz, V. N. Kalevaru, A. Bagabas, A. Martin,
ChemCatChem 2012, 4, 1330-1336.
X. Li, D. Wu, T. Lu, G. Yi, H. Su, Y. Zhang, Angew. Chem. 2014,
126, 4284-4288; Angew. Chem. Int. Ed. 2014, 53, 4200-4204.
An in situ NMR experiment monitoring the release of Cp-ligand in
the DODH reaction of 1,2-octanediol using the previously reported
Cp*ReO3 catalyst (conditions: 1,2-octanediol (0.05 mmol), PPh3
(0.055 mmol, 1.1 equiv.), mesitylene (0.05 mmol, 1.0 equiv, internal
standard), Cp*ReO3 (10 mol%), toluene-D8 (0.5 mL), 135 oC, N2)
suffered from signal overlap for free Cp*H ligand and substrate
signals in the high-field region of the NMR spectra. This has made
accurate signal integration and quantification of free Cp*-ligand
troublesome. From this experiment we estimate approximately 20%
of ligand dissociation at the end of the reaction. Free Cp* ligand was
confirmed by GC-MS analysis.
Keywords: homogenous catalysts • deoxydehydration • bio-
mass conversion • trioxo-rhenium complexes • ligand design
[1]
[2]
[3]
P. Lanzafame, G. Centi, S. Perathoner, Chem. Soc. Rev. 2014, 43,
7562-7580.
E. P. Ahern, P. Deane, T. Persson, B. Ó. Gallachóir, J. D. Mur phy,
Renewable Energy 2015, 78, 648–656.
T. Werpy, G. Petersen, A. Aden, J. Bozell, J. Holladay, J. White, A.
Manheim, D. Eliot, L. Lasure, S. Jones, Top Value Added
Chemicals from Biomass, Volume 1 – Results of Screening for
Potential Candidates from Sugars and Synthesis Gas, U.S.
Department of Energy, 2004.
[28]
[29]
J. J. J. Juliette, K. P. Gable, J. Am. Chem. Soc. 1995, 117, 955-962.
S. Vkuturi, G. Chapman, I. Ahmad, K. M. Nicholas, Inorg. Chem.
2010, 49, 4744-4746.
[4]
A. Corma Canos, S. Iborra, A. Velty, Chem. Rev. 2007, 107, 2411-
2502.
[30]
I. Ahmad, G. Chapman, K. M. Nicolas, Organometallics 2011, 30,
2810-2818.
[5]
[6]
[7]
J. J. Bozell, G. R. Petersen, Green Chem. 2010, 12, 539.
J. R. Dethlefsen, P. Fristrup, ChemSusChem 2015, 8, 767-775.
C. Boucher-Jacobs, K. M. Nicholas, Top. Curr. Chem. 2014, 353,
163-184.
[31]
[32]
J. M. McClain, K. M. Nicolas, ACS Catal. 2014, 4, 2109-2112.
H. Sun, C. Hu, Z. Hao, Y. Zuo, T. Wang, C. Zhong, Chin. J. Org.
Chem. 2015, 35, 1904-1909.
[8]
[9]
S. Raju, M. E. Moret, R. J. M. Klein Gebbink, ACS Catal. 2015, 5,
281-300.
[33]
D. S. Morris, K. van Rees, M. Curcio, M. Cokoja. F. E. Kuhn, F.
Duarte, J. B. Love, Catal. Sci. Technol. 2017, 7, 5644-5649.
J. Gossett, R. Srivastava, Tetrahedron Letters 2017, 58, 3760-3763.
J. Shakeri, H. Hadadzadeh, H. Farrokhpour, M. Joshaghani, M. Weil,
J. Phys. Chem. A 2017, 121, 8688-8696.
L. L. Adduci, M. P. McLaughlin, T. A. Bender, J. J. Becker, M. R.
Gagné, Angew. Chem. 2014, 126, 1672-1675; Angew. Chem. Int.
Ed. 2014, 53, 1646-1649.
[34]
[35]
[10]
[11]
M. Schlaf, Dalt. Trans. 2006, 4645-4653.
T. J. Korstanje, E. F. De Waard, J. T. B. H. Jastrzebski, R. J. M. K.
Gebbink, ACS Catal. 2012, 2, 2173-2181.
[12]
[13]
[14]
[15]
[16]
[17]
G. K. Cook, M. A. Andrews, J. Am. Chem. Soc. 1996, 118, 9448-
9449.
M. Shiramizu, F. D. Toste, Angew. Chem. 2012, 124, 8206-8210;
Angew. Chem. Int. Ed. 2012, 51, 8082-8086.
M. Shiramizu, F. D. Toste, Angew Chem. 2012, 125, 13143-13147;
Angew. Chemie. Int. Ed. 2013, 52, 12905-12909.
K. P. Gable, A. AbuBaker, K. Zientara, A. M. Wainwright,
Organometallics 1999, 18, 173-179.
S. Raju, J. T. B. H. Jastrzebski, M. Lutz, R. J. M. Klein Gebbink,
ChemSusChem 2013, 6, 1673-1680.
S. Raju, C. A. M. R. Van Slagmaat, J. Li, M. Lutz, J. T. B. H.
Jastrzebski, M. E. Moret, R. J. M. Klein Gebbink, Organometallics
This article is protected by copyright. All rights reserved.

10.1002/cctc.201801151
ChemCatChem
FULL PAPER
Entry for the Table of Contents (Please choose one layout)
Layout 1:
FULL PAPER
Text for Table of Contents
Author(s), Corresponding Author(s)*
Page No. – Page No.
Title
((Insert TOC Graphic here: max.
width: 5.5 cm; max. height: 5.0 cm))
Layout 2:
FULL PAPER
CpttReO3
OH
Author(s), Corresponding Author(s)*
R1
H2O
+
OH
R1
Re
Page No. – Page No.
yield up to 99%
O
O
R2 R3
OH
R2 R3
O
O
TON up to 900 per Re
CpttReO3
Title
Diols and biomass-derived polyols, the sustainable starting materials, were
efficiency converted to very useful industry building blockers (olefins) by using
CpttReO3 as catalyst and secondary alcohol as reductant. Remarkably, the loading
of CpttReO3 can be reduced to 0.1 mol% to achieve a turn-over number as high as
900 per Re when using glycerol as substrate.
This article is protected by copyright. All rights reserved.