Carba-cyclophellitols Are Neutral Retaining-Glucosidase Inhibitors

Article abstract of DOI:10.1021/jacs.7b01773

The conformational analysis of glycosidases affords a route to their specific inhibition through transition-state mimicry. Inspired by the rapid reaction rates of cyclophellitol and cyclophellitol aziridine - both covalent retaining β-glucosidase inhibitors - we postulated that the corresponding carba cyclopropyl analogue would be a potent retaining β-glucosidase inhibitor for those enzymes reacting through the ⁴H₃ transition-state conformation. Ab initio metadynamics simulations of the conformational free energy landscape for the cyclopropyl inhibitors show a strong bias for the ⁴H₃ conformation, and carba-cyclophellitol, with an N-(4-azidobutyl)carboxamide moiety, proved to be a potent inhibitor (K_i = 8.2 nM) of the Thermotoga maritima TmGH1 β-glucosidase. 3-D structural analysis and comparison with unreacted epoxides show that this compound indeed binds in the ⁴H₃ conformation, suggesting that conformational strain induced through a cyclopropyl unit may add to the armory of tight-binding inhibitor designs.

Full text of DOI:10.1021/jacs.7b01773

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Communication
Carba-Cyclophellitols are Neutral Retaining Glucosidase Inhibitors
Thomas J.M. Beenakker, Dennis Wander, Wendy A. Offen, Marta Artola, Lluís Raich, Maria J. Ferraz,
Kah-Yee Li, Judith H.P.M. Houben, Erwin R. van Rijssel, Thomas Hansen, Gijsbert A. van der Marel,
Jeroen D. C. Codée, Johannes M.F.G. Aerts, Carme Rovira, Gideon J. Davies, and Herman S. Overkleeft
J. Am. Chem. Soc., Just Accepted Manuscript • Publication Date (Web): 02 May 2017
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Carba-Cyclophellitols are Neutral Retaining Glucosidase In-
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Thomas J. M. Beenakker†, Dennis P. A. Wander†, Wendy A. Offen§, Marta Artola†, Llu s Raich¶, Maria
í
J. Ferraz‡, KahꢀYee Li†, Judith H. P. M. Houben‡, Erwin R. van Rijssel†, Thomas Hansen†, Gijsbert A.
van der Marel†, Jeroen D. C. Codée†, Johannes M. F. G. Aerts‡, Carme Rovira¶,ǁ, Gideon J. Davies§,*
and Herman S. Overkleeft†,*
†Department of Bioꢀorganic Synthesis and ‡Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden
University, Einsteinweg 55, 2300 RA Leiden, The Netherlands.
§Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K.
¶Departament de Quimica Inorganica i Organica (Secció de Química Orgànica) & Institut de Quimica Teòrica i Comꢀ
putacional (IQTCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
ǁInstitució Catalana de Recerca i Estudis Avançats (ICREA), 08020 Barcelona, Spain.
Supporting Information Placeholder
transitionꢀstate during βꢀglucosidaseꢀmediated hydrolysis of a βꢀ
glucosidic linkage.
ABSTRACT: The conformational analysis of glycosidases
affords a route into their specific inhibition through transitionꢀ
state mimicry. Inspired by the rapid reaction rates of cyclophelꢀ
litol and cyclophellitol aziridine, both covalent retaining
β−glucosidase inhibitors, we postulated that the corresponding
carba "cyclopropyl" analogue would be a potent retaining
β−glucosidase inhibitor for those enzymes reacting through the
4H3 transitionꢀstate conformation. Ab initio metadynamics simulaꢀ
tion of the conformational free energy landscape for the cycloproꢀ
4
pyl inhibitors show a strong bias for the H3 conformation and
carbaꢀcyclophellitol with an Nꢀ(4ꢀazidobutyl)carboxamide moiety
proved to be a potent inhibitor (Ki of 8.2 nM) of the Thermotoga
maritima TmGH1 β−glucosidase. 3ꢀD structural analysis and
comparison with unreacted epoxides shows that this compound
4
indeed bind in H3 conformation suggesting that conformational
strain induced through a cyclopropyl unit may add to the armory
of tight binding inhibitor designs.
The diverse conformational pathways of glycosidases1,2 (for
example Figure 1A) coupled to their phenomenal transitionꢀstate
stabilization3 offers a powerful route to selective enzyme inhibiꢀ
tion. One of the main goals of the field, very rarely achieved, is to
design and apply conformationallyꢀrestricted inhibitors in order to
provide both potency and specificity; conformationallyꢀbiased
inhibitors that target specific classes of glycoside hydrolase (GH)
would be of considerable use as cellular and mechanistic probes
and potential as starting points for therapeutic compounds. Cyꢀ
clophellitol (1, Figure 1), isolated in 1990 from the mushroom
Phellinus sp.4, is a potent mechanismꢀbased inhibitor of retaining
βꢀglucosidases. It finds primary use as a covalent inactivator of βꢀ
glucosidases.5 Cyclophellitol is a configurational analogue of βꢀ
glucopyranose, but its conformational behavior is different.
Figure 1. A) Mechanistic itinerary of retaining βꢀglucosidases. B)
Structure of cyclophellitol (1) adopting a 4H3 conformation and its
proposed mechanism of binding. C) Structure of carbaꢀ
cyclophellitol (2) in 4H3 conformation.
4
Whereas βꢀglucopyranoses preferably adopt a C1 conformation;
4
the epoxide annulation in 1 likely enforces a preferred H3 halfꢀ
chair conformation onto the cyclitol moiety. Cyclophellitol (1) is
thus a potential conformational analogue of the oxocarbenium ion
Although the mode of action of 1 is covalent (Figure 1B) the
potency and specificity of cyclophellitol (1) as a retaining βꢀ
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glucosidase inhibitor and its mode of action (entering the enzyme
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1
active site as a H3 halfꢀchair transitionꢀstate analogue followed
by SN2 displacement of the epoxide heteroatom) led us to considꢀ
er whether the corresponding carba analogue (that is, substitution
of the oxygen for carbon) would result in competitive inhibitors in
which potency and potentially specificity would be accrued by
virtue of partial transitionꢀstate mimicry (Figure 1C).
2
3
4
5
6
To test this hypothesis, a set of carbaꢀcyclophellitols was deꢀ
signed. Here we present the synthesis of carbaꢀcyclophellitols 3ꢀ5
(Figure 2), the quantum mechanical analysis of their favored
conformation and their structural and inhibitory dissection toꢀ
wards βꢀglucosidases. Carbaꢀcyclophellitols are shown to be low
ꢀM inhibitors. Furthermore, exploiting the possibility of incorpoꢀ
rating pseudoꢀaxial R groups – consistent with the catalytic itinerꢀ
ary – that bearing a hydrophobic moiety at the terminal cycloproꢀ
pyl carbon (5) was indeed a potent (low nM) inhibitor of a classiꢀ
cal model βꢀglucosidase, namely Thermotoga maritima
TmGH1.5,6 The crystal structure of TmGH1 containing carbaꢀ
cyclophellitol 5 was determined, in comparison with an unreacted
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Scheme 1. Reagents and conditions. (a) BnBr, NaH, TBAI,
DMF, 0 °C to rt., 24 h, 94%; (b) EDA, Cu(acac)2, EtOAc, (35%,
2:1, as a mixture of α/β); (c) DIBAL, THF, 30 min at 0 °C and
then 1 h at rt., 13%; (d) Jones reagent, acetone, 0 ºC, 3 h, 53%; (e)
EtOH, N,N′ꢀdiisopropylcarbodiimide, 4ꢀdimethylaminopyridine,
toluene, rt., 4 h, 62%; (f) Pd(OH)2/C, H2, EtOAc, AcOH, rt.,
overnight, 81%; (g) N,Oꢀdimethylhydroxylamine hydrochloride,
EtMgBr, THF, 48%; (h) Pd(OH)2/C, H2, MeOH, rt., overnight,
(58%); (i) i) LiOH, MeOH, H2O, rt., overnight; ii) 4ꢀazidobutanꢀ
1ꢀamine (see SI), DIPEA, HCTU, CH2Cl2, rt., overnight; (j) BCl3,
DCM, 99%.
4
cyclophellitol derivative and, as predicted, both bind in H3 conꢀ
formation, which is the presumed transition state conformation
during the TmGH1ꢀcatalysed hydrolysis of βꢀglucosidic linkages.
After having carbaꢀcyclopropane 3ꢀ5 in hand, their inhibition
potency was studied in comparison with deoxynojirimycin (DNJ),
a known competitive TmGH1 inhibitor and AMPꢀDNM (MZꢀ21),
a known human retaining βꢀglucosidase inhibitor.13 Initial binding
constant (Ki) values were determined on TmGH1 by monitoring
Figure 2. Structures of carbaꢀcyclophellitols (3ꢀ5) and 8ꢀ
azidocyclophellitol 6 (KY1707,8).
The synthesis of compounds 3ꢀ5 commenced with the easy acꢀ
cess of key intermediate 7, which was obtained via the synthetic
procedure described by the group of Madsen9 and optimized in
our laboratory (Scheme 1).8 Global benzylation of 7 gave cycloꢀ
hexene 8, and cyclopropanation with ethyl diazoacetate
(EDA)10,11 under the agency of Cu(acac)2 resulted in the forꢀ
mation of product 9 as a mixture of αꢀ and βꢀisomers (α/β, 2:1).
After the reduction step12 the βꢀisomer could be isolated by colꢀ
umn chromatography to give alcohol 10, which was oxidized and
ensuing esterification yielded enantiomerically pure βꢀester 11.
Sequential oneꢀpot formation and Grignard addition onto the
Weinreb amide yielded βꢀketone 12. Both benzylꢀprotected ester
11 and ketone 12 were subjected to palladiumꢀcatalyzed hydroꢀ
genolysis conditions in ethyl acetate and acetic acid (11) or in
methanol (12) to obtain target compounds 3 and 4. The mixture of
αꢀ and βꢀesters 9 was saponified and the resulting carboxylates
condensed with 4ꢀazidobutanꢀ1ꢀamine (see Supporting Inforꢀ
mation (SI)). The mixture of αꢀ and βꢀamides was separated by
preparative HPLC purification. Finally, the benzyl groups were
removed in the presence of the azide with anhydrous BCl3 in
dichloromethane to afford βꢀamide 5.
the UVꢀabsorbance of pꢀnitrophenolate from pꢀnitrophenyl βꢀDꢀ
glucopyranoside using the Lineweaver–Burk method. Carbaꢀ
cyclophellitol 3 and 4 showed micromolar inhibition, consistent
with our design strategy and similar to that displayed by the
charged species DNJ, whereas 5 proved to be a strong reversible
binding TmGH1 inhibitor with a Ki value of 8.2 nM, much more
potent than DNJ14 and AMPꢀDNM (low micromolar) (Table 1
and supplementary Figure S4). We then explored the activity of
compound 5 in human lysosomal retaining βꢀglucosidase, GBA1
(deficiency of which is causative of the human lysosomal storage
disorder, Gaucher disease) with an apparent IC50 of around 100
ꢀM. No apparent inhibition of the human lysosomal αꢀ
glucosidase, GAA (deficient in the human glycogen storage disꢀ
ease, Pompe disease) was observed at final concentrations of 5 up
to 150 ꢀM. Thus, although less potent for GBA1 than for the
bacterial enzyme tested, compound 5 appears to have selectivity
for the human lysosomal βꢀglucosidase over the human lysosomal
αꢀglucosidase, which is opposite of the selectivity observed for
deoxynojirimycin (DNJ, Table 1).
Table 1. Apparent IC50 values and inhibitory constants (Ki)
for in vitro inhibition of αꢀ and βꢀglucosidase activity by
compounds 3ꢀ5, DNJ and AMPꢀDNM.
Compound
TmGH1[a]
Ki[c]
22.3 µM
88.9 µM
8.20 nM
2.50 µM[d]
4.97 µM
GBA1[b]
App IC50
>150 µM
GAA[b]
App IC50
> 150 µM
> 150 µM
> 150 µM
1.5 µM[g]
0.4 ꢁM[g]
3
4
5
>150 µM
99 ± 1.9 ꢁM
109 ± 1.0 ꢁM[e]
156 ± 16 nM[f]
DNJ
AMPꢀDNM
(MZꢀ21)
The assay was performed with (a) pꢀNPG or (b) 2,4ꢀDNPG as
substrate. (c) Km TmGH1 = 0.24 mM. Values in agreement with
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literature: (d) Ki DNJ = 3.8 ꢁM in TmGH114, (e) IC50 DNJ = 250
ꢁM in GBA115, (f) IC50 AMPꢀDNM = 100ꢀ200 nM in GBA115,16
(g) values from reference.17 App: apparent.
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2
.
3
4
5
Inspired by the low µM to nM inhibition of TmGH1 by the carꢀ
baꢀcyclopropanes, we sought to determine whether the cycloproꢀ
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pyl moiety indeed biased the conformation to H3. We calculated
the conformational free energy landscape (FEL) for generic cyꢀ
cloproyl (2, R = H) by ab initio metadynamics (see SI), and the
CremerꢀPople puckering coordinates θ and ϕ were used as collecꢀ
tive variables, yielding a Mercator representation for the FEL (as
used previously for diverse glycosidase inhibitors18ꢀ20), Figure 3A.
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Compound 2 clearly favors the H3 conformation in vacuo, with
3
the flipped H4 form in another local energy minimum. Subseꢀ
quent to FEL calculation, we compared the experimental J values
of several (cyclohexane) ring protons of compound 4 with their
calculated counterparts, in which calculations were performed on
4
compound 4 in the H3 conformation. Both sets of values are in
good agreement, which underscores the notion that compound 4,
and by extension also the other compounds subject of this paper
(whose proton NMR give broadened signals due to the amide
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present – see SI) do indeed adopt the H3 conformation in soluꢀ
tion.
Structural dissection of the inhibitory action of 5, and the conꢀ
ceptual link through to cyclophellitol 1, was achieved first by
rapid soaking (as opposed to preꢀincubation as used previously to
trap the covalent adduct5) of crystals of TmGH1 with cyclophelꢀ
litol derivative KY1707,8 (6). Serendipitously, this indeed afforded
the unreacted cyclophellitol KY170 in 4H3 conformation, with the
nucleophile poised to attack, Figure 3B, confirming our hypotheꢀ
sis that (unreacted) cyclophellitols adopt a transitionꢀstate like 4H3
conformation. In order to dissect similar mimicry by carbaꢀ
cyclopropane 5, and confirm the FEL calculated by ab initio
metadynamics, TmGH1 crystals were soaked with carbaꢀ
cyclophellitol 5 and the subsequently obtained structure was
analyzed and solved with Xꢀray crystallography. The obtained
electron density pattern clearly demonstrates the presence of
Figure 3. A) A mercator representation for the computed free
energy landscape (FEL) of cyclopropyl (2, R = H) (θ and ϕ are
given in degrees). B) Crystal structure of TmGH1 in complex with
unreacted KY170. C) Crystal structure of TmGH1 in complex
with carbaꢀcyclophellitol 5, showing the carbaꢀcyclophellitolꢀCOꢀ
NH group. Electron density maps for both B and C are maximum
likelihood / σA weighted 2FobsꢀFcalc syntheses contoured at 1.4σ.
D) Overlay of (B) in ice blue on (C) in coral.
4
carbaꢀcyclophellitol 5 in the active site in H3 conformation (Figꢀ
ure 3C; the butyl azide moiety is mobile and differently disorꢀ
dered in the structure and not shown for clarity).
Overlay of cyclophellitol derivative KY170 with carbaꢀ
cyclophellitol 5 (Figure 3D) shows almost perfect coincidence of
atomic position showing that, as suggested by the FEL, 5 is a
permanent mimic of cyclophellitol posted in the active site prior
to nucleophilic attack.
The improved binding of 5, relative to 3 and 4 presumably stems
from desolvation caused by the alkylꢀazido “tail” sitting in the
aglycone site. One of the design advantages of the carbaꢀ
cyclopropanes is that any pendent R groups are disposed pseudoꢀ
axial to the sugar ring, consistent with the distortions seen during
catalysis which presumably adds to their augmentation of binding.
The 3ꢀD structure with 5 confirms this and shows a lateral, antiꢀ
trajectory interaction of the catalytic amino acid Glu166 with the
pseudoꢀaxially disposed amide of 5. There are 4 molecules of
TmGH1 in the crystallographicallyꢀobserved asymmetric unit.
Whilst they all show the R group axial, they all show different
degrees of disorder of this alkyl region itself. In one molecule,
there is essentially no electron density for the tail, whilst in two
molecules the chain passes through the aglycon region (that is
flanked by Val169 and Trps168 and 324) making nonꢀspecific
interactions with this region. In the fourth molecule of the AU, the
alkyl azido chain appears to follow two separate routes along each
hydrophobic flank of the substrate binding cleft.
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(1)
308.
(2)
Curr. Opin. Struc. Biol. 2014, 28, 1.
Davies, G. J.; Planas, A.; Rovira, C. Acc. Chem. Res. 2012, 45,
Bicyclic cyclopropyl glucosidase inhibitors, with the bridge beꢀ
tween the “C6” and “O5” atoms were first proposed by Tanaka
and coꢀworkers21 and later developed in galacto configuration by
Bennet and coꢀworkers and found to be good αꢀglucosidase and
galactosidase inhibitors, respectively.22 More recently, activated
forms of these compounds have been used as covalent inhibiꢀ
tors.23 In these cases the conformational restriction limits the
accessible conformations to “offꢀpathway” 3H2 and 2H3 halfꢀ
chairs23 (or perhaps their related 1,4 boats) recently elegantly
revealed by Xꢀray crystallography.24 Further, Stick and Stubbs25
synthesized a bicyclic cyclopropyl inhibitor with the bridge beꢀ
tween the “anomeric” C1 carbon position and the “C2” atom with
a millimolar Ki value. The carbaꢀcyclophellitol derivatives preꢀ
sented here offer, by virtue of the advantage of their conformaꢀ
tional restriction between the “O5” and “anomeric” C1 carbon
position a potent inhibitor in which the conformational restrain is
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Speciale, G.; Thompson, A. J.; Davies, G. J.; Williams, S. J.
(3)
(4)
Wolfenden, R.; Snider, M. J. Acc. Chem. Res. 2001, 34, 938.
Atsumi, S.; Umezawa, K.; Iinuma, H.; Naganawa, H.; Nakaꢀ
mura, H.; Iitaka, Y.; Takeuchi, T. J. Antibiot. 1990, 43, 49.
(5) Gloster, T. M.; Madsen, R.; Davies, G. J. Org. Biomol. Chem.
2007, 5, 444.
(6)
Gloster, T. M.; Meloncelli, P.; Stick, R. V.; Zechel, D.;
Vasella, A.; Davies, G. J. J. Am. Chem. Soc. 2007, 129, 2345.
(7)
Witte, M. D.; Kallemeijn, W. W.; Aten, J.; Li, K.ꢀY.; Strijland,
9
A.; DonkerꢀKoopman, W. E.; van den Nieuwendijk, A. M. C. H.;
Bleijlevens, B.; Kramer, G.; Florea, B. I.; Hooibrink, B.; Hollak, C. E. M.;
Ottenhoff, R.; Boot, R. G.; van der Marel, G. A.; Overkleeft, H. S.; Aerts,
J. M. F. G. Nat. Chem. Biol. 2010, 6, 907.
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(8)
Li, K.ꢀY.; Jiang, J.; Witte, M. D.; Kallemeijn, W. W.; van den
Elst, H.; Wong, C.ꢀS.; Chander, S. D.; Hoogendoorn, S.; Beenakker, T. J.
M.; Codée, J. D. C.; Aerts, J. M. F. G.; van der Marel, G. A.; Overkleeft,
H. S. Eur. J. Org. Chem. 2014, 2014, 6030.
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a glycosidase reaction coordinate relevant H3. Given the large
number of glycosidase inhibitors in medical use, including those
being developed as pharmacological chaperones and as diagnostic
tools, the harnessing of appropriate conformation restraint, couꢀ
pled to correct stereochemistry should add greatly to the enzymoꢀ
logical, cellular and, ultimately, therapeutic toolbox.
(9)
70, 10139.
(10)
Hansen, F. G.; Bundgaard, E.; Madsen, R. J. Org. Chem. 2005,
Ye, T.; McKervey, M. A. Chem. Rev. 1994, 94, 1091.
(11)
Caballero, A.; Prieto, A.; DiazꢀRequejo, M. M.; Pérez, P. J.
Eur. J. Inorg. Chem. 2009, 2009, 1137.
(12)
Zhou, S.; Kern, E. R.; Gullen, E.; Cheng, Y.ꢀC.; Drach, J. C.;
ASSOCIATED CONTENT
Supporting Information
Tamiya, S.; Mitsuya, H.; Zemlicka, J. J. Med. Chem. 2006, 49, 6120.
(13)
Overkleeft, H. S.; Renkema, G. H.; Neele, J.; Vianello, P.;
Hung, I. O.; Strijland, A.; van der Burg, A. M.; Koomen, G. J.; Pandit, U.
K.; Aerts, J. M. J. Biol. Chem. 1998, 273, 26522.
1
Experimental procedures, supporting figures and tables and H
(14)
Zechel, D. L.; Boraston, A. B.; Gloster, T.; Boraston, C. M.;
and 13C NMR spectra (PDF).
Macdonald, J. M.; Tilbrook, D. M. G.; Stick, R. V.; Davies, G. J. J. Am.
Chem. Soc. 2003, 125, 14313.
The Supporting Information is available free of charge on the
ACS Publications website.
(15)
Wennekes, T.; Meijer, A. J.; Groen, A. K.; Boot, R. G.;
Groener, J. E.; van Eijk, M.; Ottenhoff, R.; Bijl, N.; Ghauharali, K.; Song,
H.; O’Shea, T. J.; Liu, H.; Yew, N.; Copeland, D.; van den Berg, R. J.;
van der Marel, G. A.; Overkleeft, H. S.; Aerts, J. M. J. Med. Chem. 2010,
53, 689.
AUTHOR INFORMATION
Corresponding Author
(16)
Ghisaidoobe, A. T.; van den Berg, R. J. B. H. N.; Butt, S. S.;
Strijland, A.; DonkerꢀKoopman, W. E.; Scheij, S.; van den Nieuwendijk,
A. M. C. H.; Koomen, G.ꢀJ.; van Loevezijn, A.; Leemhuis, M.; Wennekes,
T.; van der Stelt, M.; van der Marel, G. A.; van Boeckel, C. A. A.; Aerts,
J. M. F. G.; Overkleeft, H. S. J. Med. Chem. 2014, 57, 9096.
h.s.overkleeft@lic.leidenuniv.nl
gideon.davies@york.ac.uk
Notes
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Wennekes, T.; van den Berg, R. J. B. H. N.; Donker, W.; van
The authors declare no competing financial interests.
der Marel, G. A.; Strijland, A.; Aerts, J. M. F. G.; Overkleeft, H. S. J. Org.
Chem. 2007, 72, 1088.
(18)
Petricevic, M.; Sobala, L. F.; Fernandes, P. Z.; Raich, L.;
ACKNOWLEDGMENT
Thompson, A. J.; BernardoꢀSeisdedos, G.; Millet, O.; Zhu, S.; Sollogoub,
M.; JiménezꢀBarbero, J.; Rovira, C.; Davies, G. J.; Williams, S. J. J. Am.
Chem. Soc. 2017, 139, 1089.
We thank the Netherlands Organization for Scientific Research
(NWOꢀCW, ChemThem grant to J.M.A. and H.S.O.), the Europeꢀ
an Research Council (ERCꢀ2011ꢀAdGꢀ290836 “Chembiosphing”,
to H.S.O., and ERCꢀ2012ꢀAdGꢀ32294 “Glycopoise’, to G.J.D.),
the Spanish Ministry of Economy and Competitiveness
(CTQ2014ꢀ55174, to C.R.) and the Generalitat de Catalunya
(2014SGRꢀ987, to C.R.) for financial support. L.R. thanks the
University of Barcelona for an APIF predoctoral fellowship. We
gratefully acknowledge the computer resources at MareNostrum
and the technical support provided by BSCꢀCNS (RESꢀQCMꢀ
2016ꢀ3ꢀ00017). We thank the European Synchrotron Radiation
Facility at Grenoble for access to beamline ID23ꢀ2 and the Diaꢀ
mond Light Source for access to beamline IO2 (proposal number
mxꢀ13587) that contributed to the results presented here.
(19)
Thompson, A. J.; Dabin, J.; IglesiasꢀFernández, J.; Ardèvol,
A.; Dinev, Z.; Williams, S. J.; Bande, O.; Siriwardena, A.; Moreland, C.;
Hu, T.ꢀC.; Smith, D. K.; Gilbert, H. J.; Rovira, C.; Davies, G. J. Angew.
Chem. Int. Ed. 2012, 51, 10997.
(20)
Williams, R. J.; IglesiasꢀFernández, J.; Stepper, J.; Jackson, A.;
Thompson, A. J.; Lowe, E. C.; White, J. M.; Gilbert, H. J.; Rovira, C.;
Davies, G. J.; Williams, S. J. Angew. Chem. Int. Ed. 2013, 53, 1087.
(21)
Tanaka, K. S. E.; Winters, G. C.; Batchelor, R. J.; Einstein, F.
W. B.; Bennet, A. J. J. Am. Chem. Soc. 2001, 123, 998.
(22)
(23)
Wang, Y.; Bennet, A. J. Org. Biomol. Chem. 2007, 5, 1731.
Chakladar, S.; Wang, Y.; Clark, T.; Cheng, L.; Ko, S.; Vocadꢀ
lo, D. J.; Bennet, A. J. Nat. Commun. 2014, 5, 1.
(24) Adamson, C.; Pengelly, R. J.; Shamsi Kazem Abadi, S.; Chakꢀ
ladar, S.; Draper, J.; Britton, R.; Gloster, T. M.; Bennet, A. J. Angew.
Chem. Int. Ed. 2016, 128, 15202.
(25)
Stick, R. V.; Stubbs, K. A. J. Carbohyd. Chem. 2005, 24, 529.
REFERENCES
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