Halohydrin dehalogenase (HheC) can perform enantioselective azidolysis of aromatic epoxides to 1,2-azido alcohols which are subsequently ligated to alkynes producing chiral hydroxy triazoles in a one-pot procedure with excellent enantiomeric excess.

Campbell-Verduyn, Lachlan S.,

Dierckx, Rudi A.,

Elsinga, Philip H.,

Feringa, Ben L.,

Janssen, Dick B.,

Postema, Christiaan P.,

Szymański, Wiktor,

English

Campbell-Verduyn, Lachlan S.

Szymanski, Wiktor

Postema, Christiaan P.

Dierckx, Rudi A.

Elsinga, Philip H.

Janssen, Dick B.

Feringa, Ben L.

University of Groningen Research Database

One pot 'click' reactions:tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition

Halohydrin dehalogenase (HheC) can perform enantioselective azidolysis of aromatic epoxides to 1,2-azido alcohols which are subsequently ligated to alkynes producing chiral hydroxy triazoles in a one-pot procedure with excellent enantiomeric excess

NARCIS 

One pot 'click' reactions: tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition

University of Groningen Digital Archive

One Pot ‘Click’ Reactions: Tandem Enantioselective Biocatalytic Epoxide Ring 
Opening and [3+2] Azide Alkyne Cycloaddition 
 
L.S. Campbell-Verduyn
a, W. Szymanski 
a, C.P. Postema
b, R. A. Dierckx
c, P. H. Elsinga
c, 
D.B. Janssen
b  and B. L. Feringa
a* 
 
a Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG 
Groningen, the Netherlands. 
bBiochemical Laboratory, Groningen Biomolecular Sciences and Biotechnology Institute, 
University of Groningen, Nijenborgh 4, 9747 AG, Groningen, the Netherlands 
c Department of Nuclear Medicine and Molecular Imaging,  University Medical Center  
Groningen, University of Groningen, Groningen, The Netherlands. 
 
 
 
 
Supplementary Information 
 
 
Table of Contents 
 
General………………………………………………………………………………….2 
 
Experimental Procedures...………………………….. …………………………………3 
 
Enzyme Preparation……….…………………………………………………………….4 
 
Synthesis and Characterization of Substrates and Reference Compounds…....…...........5 
 
References……………………...………………………………………………………..9 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010General 
 
All reactions were carried out in oven dried glassware. CuSO4·5H2O, sodium ascorbate 
and sodium azide were purchased from Sigma-Aldrich and used as received. 
1H- and 
13C-
NMR were recorded on a Varian AMX400 (400 and 100.59 MHz) using CDCl3 as 
solvent unless otherwise indicated. Chemical shift values are reported in ppm with the 
solvent resonance as the internal standard (CHCl3: δ 7.26 for 
1H and δ 77.0 for 
13C). Data 
are reported as follows: chemical shifts, multiplicity (s=singlet, d=doublet, t=triplet, 
q=quartet, dd=doublet of doublets, dt=doublet of triplets, td=triplet of doublets, 
m=multiplet, br=broad), coupling constants (Hz), and integration. Flash chromatography 
was performed on silica gel. All thin layer chromatography was performed on Merck F-
254 silica gel plates. Visualization of the TLC plates was performed with KMnO4 
staining reagent and UV light (254 nm). Mass spectra were recorded on an AEI-MS-902 
mass spectrometer by EI (70 eV) measurements. Melting points are uncorrected. 
MonoPhos was synthesized as described in the literature (1).  
1H and 
13C NMR data are 
provided for all synthesized compounds. Spectra were in accordance with published 
experimental data and references are provided for known compounds. HRMS mass data 
is provided for all new compounds. Enantioselectivities were determined by HPLC 
analysis using a Shimadzu LC-10ADVP HPLC equipped with a Shimadzu SPD-
M10AVP diode array detector. 
 
 
 
Safety 
 
Working with azides should always be done carefully. Organic azides, particularly those 
of low molecular weight, or with high nitrogen content, are potentially explosive. Heat, 
light and pressure can cause decomposition of the azides. Furthermore, the azide ion is 
toxic, and sodium azide should always be handled while protected with gloves. Heavy 
metal azides are particularly unstable, and may explode if heated or shaken.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010Experimental Information 
 
General Procedure for Biocatalyzed Azidolysis of Epoxides: 
 
To a 15.0 mL Greiner tube was added 1.0 eq of epoxide (0.032 mmol) and 10.0 mL of 50 
mM potassium phosphate buffer (pH 7.5). To this solution was added 0.6 eq of sodium 
azide followed by 0.5 mL of potassium phosphate buffer containing 25 U (initial activity) 
of halohydrin dehalogenase. The reaction mixture was shaken overnight and the resulting 
solution extracted with diethyl ether (3 x 5 mL). The organic layers were combined and 
dried over MgSO4. Solvent was removed under reduced pressure to give the crude 
reaction products which were analyzed by HPLC.  
 
 
 
General Procedure for One-Pot Enzymatic Click Reactions:  
 
Copper Catalyzed Procedure 
To a 15.0 mL Greiner tube was added 5 mol % CuSO4·5H2O  and 25 mol % sodium 
ascorbate followed by 1.0 mL of 50 mM potassium phosphate buffer. To this solution 
was added 5.5 mol % MonoPhos and the resulting mixture was shaken for 10 min. 
Sodium azide (0.6 eq) and epoxide (1.0 eq, 0.032 mmol) were added to the reaction 
mixture, which was diluted with a further 6 mL of buffer (volume varied depending on 
the substrate concentration desired). To this solution was added 2.0 eq of alkyne, 
followed by 0.5 mL of buffer containing 25 U (initial activity) of halohydrin 
dehalogenase. The Greiner tube was placed on a shaker and after 24 h, the reaction 
mixture was lipholized overnight. The resulting solid content was flushed over a short 
plug of silica with ethyl acetate, followed by methanol. Solvent was removed under 
reduced pressure and the crude reaction mixture was prepared for analysis by HPLC.  
 
Copper Free Procedure  
To a 15.0 mL Greiner tube was added 1.0 eq of epoxide (0.032 mmol, 5.0 mg) and 7.0 
mL of potassium phosphate buffer (50 mM). To this reaction mixture was added 2.0 eq of 
cyclooctyne (2) followed by 0.5 mL of potassium phosphate buffer containing 25 U 
(initial activity) of halohydrin dehalogenase. The reaction vessel was sealed with parafilm 
and shaken for the indicated amount of time (24 or 48 h). The reaction mixture was then 
lipholized overnight and the resulting solid flushed over silica with ethyl acetate followed 
by methanol. Solvent was removed under reduced pressure to yield the crude reaction 
mixture which could be analyzed by HPLC.  
 
 
 
 
 
 
 
 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010Enzyme Preparation 
 
Halohydrin dehalogenase was expressed in E. coli MC1061 using the pBAD vector (3,4). 
Transformed cells were streaked on Luria Broth (LB) agar plates containing ampicillin 
and incubated overnight at 37 °C. A preculture was started by inoculating 100 mL LB 
containing 50 μg/ml ampicillin with one colony from the plate. After overnight 
incubation at 37 °C, the preculture was diluted in 1 L of Terrific Broth (TB) containing 
50 μg/mL ampicillin, 0.5 M sorbitol and 0.02% arabinose. This main culture was 
incubated for two days at 37 °C. 
The cells were centrifuged (10 min, 13 000 g), washed, and resuspended in 5 mL/g pellet 
of TEG buffer (10 mM Tris-SO4 pH=7.5, 1 mM EDTA and 10% glycerol). Cells were 
broken by sonication and the extract was centrifuged (160, 000 g, 45 min, 4 °C). The 
supernatant was applied on a Q-Sepharose column (50 mL, GE Healthcare) (4) and 
elution was carried out with a gradient of 0 to 0.45 M (NH4)2SO4  in TEG. The collected 
fractions that displayed enzymatic activity were pooled. (NH4)2SO4 was added to a 
concentration of 1.5 M and the protein was applied on a Phenyl-Sepharose column (60 
mL, GE Healthcare). Elution was carried out with a gradient of 1.5 M to 0 M (NH4)2SO4 
in TEG. Fractions that displayed enzymatic activity were pooled and concentrated over a 
10 kDa filter (Millipore). The enzyme was 97% pure judged by SDS-PAGE. Purified 
enzyme was sterilized using a 0.2 μm filter and stored at -70°C. Enzyme assay was 
carried out as previously described using 1-(p-nitrophenyl)-2-bromoethanol (5). The 
concentration was determined to be 25 U/mL and the specific activity 20 U/mg.   
 
Buffer Exchange 
 
The enzyme was transferred from Tris-HCl buffer to potassium phosphate 
buffer (pH 7.5, 50 mM). The Tris-buffer solution was loaded onto a 10 kDa 
filter (Millipore) in 500 μL fractions and spun down (14,000 g, 30 min, 4 º C). After 
the protein was loaded, the filter was flushed twice with potassium phosphate buffer (500 
μL each) prior to elution from the filter (1,000 g, 3 min, 4 º C).   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010Characterization of substrates and reference compounds 
 
 
 
2-azido-1-phenylethanol. 2-azido-1-phenylethanol was prepared as described in the 
literature (6) and NMR data was in accordance with the literature. Enantiomeric excess 
determined by HPLC (Chiralpak OD 99:1 Heptane: i-PrOH: tr= 42.2, 47.0 min). 
1H NMR 
(400 MHz, CDCl3): δ 7.26-7.39 (m, 5H), 4.89 (dd, J= 4.4, 3.6 Hz, 1H), 3.47 (m, 2H), 
2.40 (br s, 1H).  
 
 
 
1-phenyl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)ethanol. To a 10.0 mL roundbottom flask 
was added 10.9 mg (0.07 mmol) of 2-azido-1-phenylethanol and 15 μL (0.13 mmol) of 
phenylacetylene. CuSO4
. 5H2O (0.85 mg, 0.0034 mmol) was weighed into a small sample 
vial along with Na ascorbate (3.37 mg, 0.017 mmol) and dissolved in 1.0 mL distilled 
H2O. To this solution was added MonoPhos (1.34 mg) and the solution was stirred at 
room temperature for 15 min. The solution in the sample vial was added to the 
roundbottom flask (with stirring) and a further 2.0 mL of water and 1.0 mL of DMSO 
were added to the mixture. The reaction mixture was allowed to stir at room temperature 
overnight, and in the morning a pale yellow precipitate had formed. 5.0 mL of ice cold 
distilled water was added to the reaction mixture and the precipitate was filtered off and 
washed with cold water. The product proved to be sufficiently pure to prevent the need 
for any further purification steps. Yield= 83%. mp 156-157 ºC  Enantiomeric excess 
determined by HPLC (Chiralcel OD-H 80:20 Heptane: i-PrOH: tr= 18.0, 22.2 min). 
1H 
NMR (400 MHz, CDCl3): δ 7.78 (s, 1H), 7.73 (d, J= 6.8 Hz, 1H), 7.32-7.41 (m, 8H), 
5.24 (d, J= 6.8 Hz, 1H), 4.65 (d, J= 13.6 Hz, 1H), 4.46 (q, J= 8.8 Hz, 1H), 3.61 (s, 1H); 
13C NMR (100.59 MHz, d6-DMSO): 146.7, 142.9, 131.7, 129.8, 129.1, 128.6, 128.4, 
126.9, 125.9, 122.8, 72.3, 57.6. HRMS (EI) for C16H15N3O: (m/z)= 266 (100 %, M + H
+). 
Calculated mass: 266.1293, measured mass: 266.1288.   
 
 
 
 
2-(4-nitrophenyl)oxirane. 2-chloro-1-(4-nitrophenyl)ethanol (1.0 mmol, 201.6 mg) was 
dissolved in 3.0 mL MeOH. 1.0 mL of distilled H2O was slowly added to the solution 
with stirring. K2CO3 was then added to the solution, and the reaction mixture was 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010allowed to stir at room temperature for a further 3 h. The reaction was monitored by thin 
layer chromatography (4:1 pentane:ether). The reaction mixture was poured onto 20 mL 
of H2O and extracted with diethyl ether (3 x 10 mL). The organic fractions were collected 
and dried over MgSO4. Solvent was removed under reduced pressure and the resulting oil 
was purified by column chromatography (pentane:ether 4:1). The resulting product was a 
yellow solid. Yield= 89 %.  Enantiomeric excess determined by HPLC (Chiralpak AS-H 
90:10 Heptane: i-PrOH: tr= 14.8, 18.3 min) or (Chiralcel OD-H 80:20 Heptane: i-PrOH: 
tr= 12.2, 12.8 min). 
1H NMR (400 MHz, CDCl3): δ 8.17 (d, J= 11.2 Hz, 2H), 7.42 (d, J= 
11.2 Hz, 2H), 3.95 (m, 1H), 3.22 (m, 1H), 2.76 (m, 1H); 
13C NMR (100.59 MHz, 
CDCl3): 147.7, 145.2, 126.1, 123.6, 51.6, 51.3. 
 
 
 
 
2-azido-1-(4-nitrophenyl)ethanol. 2-bromo-1-(4-nitrophenyl)ethanol (500.0 mg, 2.25 
mmol) was dissolved in 75.0 mL DMF in a 200 mL roundbottom flask. NaN3 (732.0 mg, 
11.3 mmol) was added to solution, and the flask equipped with a condenser was heated to 
100 ºC. The reaction mixture was left overnight with stirring. In the morning, the solution 
was poured onto 50 mL of brine followed by extraction with diethyl ether (3 x 25 mL). 
The organic layers were collected and dried over MgSO4 and the solvent was removed 
under reduced pressure. The resulting oil was purified by column chromatography (1:1 
pentane:ether) to give the pure azidoalcohol as a yellow oil. Yield= 57%. Enantiomeric 
excess determined by HPLC (Chiralcel OD-H 80:20 Heptane: i-PrOH: tr= 13.0, 13.6 min, 
or, Chiralpak AS-H 90:10 Heptane: i-PrOH: tr: 28.6, 34.8 min) . 
1H NMR (400 MHz, 
CDCl3): δ 8.20 (d, J= 12 Hz, 2H), 7.56 (d, J= 12 Hz, 2H), 4.99 (dd, J= 4.0, 3.6 Hz, 1H), 
3.49 (m, 2H), 3.00 (br s, 1H); 
13C NMR (100.59 MHz, CDCl3): 147.7, 126.8, 123.9, 
123.7, 72.3, 57.6.  
 
 
 
 
1-(4-nitrophenyl)-2-(4-phenyl-1H-1,2,3-triazol-1-yl)ethanol. To a 10.0 mL 
roundbottom flask was added 46.9 mg (0.23 mmol) of 2-azido-1-(4-nitrophenyl)ethanol 
and 46.0 mg (0.05 mL, 0.45 mmol) of phenylacetylene. CuSO4
. 5H2O (0.57 mg, 0.0023 
mmol) was weighed into a small sample vial along with Na ascorbate (2.28 mg, 0.012 
mmol) and dissolved in 1.0 mL distilled H2O. To this solution was added MonoPhos 
(0.91 mg, 0.0025 mmol) and the solution was stirred at room temperature for 15 min. The 
solution in the sample vial was added to the roundbottom flask (with stirring) and a 
further 2.0 mL of water was added to the mixture. The reaction mixture was allowed to 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010stir at room temperature for 6 h and the progress of the reaction was monitored by thin 
layer chromotography (2:1 pentane:ether). Upon completion of the reaction, the mixture 
was poured onto ice water and extracted with DCM (3 x 5 mL). The organic layers were 
combined, dried over MgSO4 and the solvent was removed under reduced pressure to 
yield a yellow solid. The solid was washed with chloroform and water and then dried. 
Yield= 74 %. mp 189-190 ºC. Enantiomeric excess determined by HPLC (Chiralpak AS-
H 80:20 Heptane: i-PrOH: tr= 37.1, 36.7 min). 
1H NMR (400 MHz, d6-acetone): δ 8.34 
(s, 1H), 8.25 (d, J= 4.8 Hz, 2H), 7.88 (d, J= 7.6 Hz, 2H), 7.76 (d, J= 8.8 Hz, 2H), 7.43 (t, 
J=  7.2 Hz, 2H), 7.34 (t, J= 7.6 Hz, 1H), 5.43 (m, 2H), 4.78 (dd, J= 12, 3.6 Hz, 1H), 4.68 
(dd, J= 16, 7.2 Hz, 1H); 
13C NMR (100.59 MHz, d6-acetone):149.5, 147.9, 147.0, 131.7, 
129.0, 127.9, 127.5, 125.5, 123.6, 121.9, 71.8, 56.9. HRMS (EI) for C16H14N4O3: (m/z)= 
311 (100 %, M + H
+). Calculated mass: 311.1144, measured mass: 311.1139.   
 
 
 
 
2-(4,5,6,7,8,9-hexahydro-1H-cycloocta[d][1,2,3]triazol-1-yl)-1-(4-nitro phenyl) 
ethanol.  2-azido-1-(4-nitrophenyl)ethanol (10.7 mg, 0.05 mmol) was dissolved in 1.0 
mL dry THF in a Schlenk vessel under N2 atmosphere. 2.0 eq of cyclooctyne was added 
and the solution was stirred at room temperature overnight. Progress of the reaction was 
followed by GC/MS. THF and any remaining cyclooctyne were removed by rotary 
evaporated and the resulting viscous yellow oil was purified by column chromatography 
(5:1 pentane: ethyl acetate) to give the product as a yellow oil. Yield= 43 %. 
Enantiomeric excess determined by HPLC (Chiralcel OD-H 80:20 Heptane: i-PrOH: tr= 
15.9, 17.2 min). 
1H NMR (400 MHz, CDCl3): δ 8.23 (d, J= 8.4 Hz, 2H), 7.58 (d, J= 8.4 
Hz, 2H), 5.45 (dd, J= 8.0, 3.2 Hz, 1H), 4.43 (dd, J= 13.8, 3.2 Hz, 1H), 4.29 (J= 13.8, 8.0 
Hz, 1H), 2.87 (br m, 2H), 2.66 (br m, 2H), 1.64-1.72 (m, 4H), 1.32-1.45 (m, 4H); 
13C 
NMR (100.59 MHz, d6-CDCl3): 148.0, 147.6, 127.1, 124.1, 118.7, 113.2, 71.8, 55.4, 
27.9, 26.1, 25.9, 24.6, 23.9, 22.2. HRMS (EI) for C16H20N4O3: (m/z)= 317 (100 %, M + 
H
+). Calculated mass: 317.1608, measured mass: 317.1608.   
 
 
N
N
N
NO2
OH
O
HO
 
 
 
1-(2-hydroxy-2-(4-nitrophenyl)ethyl)-1H-1,2,3-triazole-4-carboxylic acid. 2-azido-1-
(4-nitrophenyl)ethanol (50.0 mg, 0.24 mmol) was added to a 10.0 mL roundbottom flask 
followed by propiolic acid (18.5 mg, 0.26 mmol). In a separate vial, CuSO4
. 5H2O (3.0 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010mg, 0.012 mmol) was dissolved in 1.0 mL distilled H2O along with Na ascorbate (11.9 
mg, 0.06 mmol). MonoPhos (4.7 mg) was then added to the sample vial along with 0.3 
mL DMSO. The solution was stirred at room temperature for 15 minutes. The contents of 
the sample vial were then added to the roundbottom flask with stirring and a further 3.0 
mL of distilled water and 0.5 mL of DMSO were added. Stirring of the reaction mixture 
was continued stirring at room temperature overnight. The solution was poured onto ice 
water and extracted with ethyl acetate (3 x 10 mL). The organic layers were collected and 
dried over MgSO4. The solvent was removed under reduced pressure and the resulting 
yellow oil was purified by column chromatography (1:1 pentane: ether). The product 
could also be purified by recrystallization from methanol to give a white solid. Yield= 75 
%. mp 163-164 ºC. Enantiomeric excess determined by HPLC (Chiralpak OD-H 80:20 
Heptane: i-PrOH: tr= 23.9, 28.2 min). 
1H NMR (400 MHz, CD3OD): δ 8.48 (s, 1H), 8.21 
(d, J= 8.8 Hz, 2H), 7.64 (d, J= 8.8 Hz, 2H), 5.26 (dd, J= 4.0, 3.6 Hz, 1H), 4.76 (dd, J= 
13.8, 3.6 Hz, 1H), 4.63 (dd, J= 13.8, 8.0 Hz, 1H); 
13C NMR (100.59 MHz, CD3OD): 
162.7, 148.7, 147.8, 129.2, 127.9, 127.1, 123.4, 71.1, 56.9. HRMS (EI) for C11H10N4O5: 
(m/z)= 279 (100 %, M + H
+). Calculated mass: 279.0729, measured mass: 279.0724. 
 
 
N
N
N
NO2
OH
O
O
 
 
Ethyl-1-(2-hydroxy-2-(4-nitrophenyl)ethyl)-1H-1,2,3-triazole-4-carboxylate.  
2-azido-1-(4-nitrophenyl)ethanol (50.0 mg, 0.24 mmol) was added to a 10.0 mL 
roundbottom flask. In a sample vial, CuSO4
.5H2O (3.0 mg, 0.012 mmol) and Na 
ascorbate (11.9 mg, 0.06 mmol) were dissolved in 1.0 mL of distilled water. To this 
solution was added 4.7 mg of MonoPhos in 0.3 mL of DMSO. The mixture was stirred at 
room temperature for 15 min. The solution of copper was then added to the roundbottom 
vial and a further 3.0 mL of water and 0.5 mL of DMSO were added. To this stirred 
solution was added dropwise ethyl propiolate (47.0 mg, 48.5 μL). The yellow solution 
was allowed to stir at room temperature overnight and in the morning a yellow precipitate 
had formed. 5.0 mL of ice cold distilled water was added to the solution and the 
precipitate was filtered off, washed with water and dried. Yield= 73 %. mp=152-153 ºC. 
Enantiomeric excess determined by HPLC (Chiralcel OD-H 80:20 Heptane: i-PrOH: tr= 
18.9, 25.2 min). 
1H NMR (400 MHz, d6-acetone): δ 8.52 (s, 1H), 8.24 (d, J= 8.4 Hz, 2H), 
7.76 (d, J= 8.4 Hz, 2H), 5.48 (s, 1H), 5.44 (m, 1H), 4.85 (dd, J= 14.4, 3.6 Hz, 1H), 4.71 
(dd, J= 16.0, 6.0 Hz, 1H), 4.34 (q, J= 7.2 Hz, 2H), 1.34 (t, J= 7.2 Hz, 3H); 
13C NMR 
(100.59 MHz, d6-acetone): 160.2, 149.1, 129.6, 128.4, 127.5, 123.6, 116.1, 71.4, 60.6, 
56.8, 13.9. HRMS (EI) for C13H14N4O5: (m/z)= 307 (100 %, M + H
+). Calculated mass: 
307.1042, measured mass: 307.1037.  
 
 
 
 
Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2010 
References 
 
1) H. Bernsmann, M. van den Berg, R. Hoen, A. J. Minnaard, G. Mehler, M. T. Reetz, J. 
G. De Vries and B. L. Feringa. J. Org. Chem., 2005, 70, 943-951.  
 
2) L. Brandsma, H. D. Verkruijsse. Synthesis, 1977, 290.   
 
3) R. M. Haak, F. Berthiol, T. Jerphagnon, A. J. Gayet, C. Tarabiono, C. P. Postema, V. 
Ritleng, M. Pfeffer, D. B. Janssen, A. J. Minnaard, B. L. Feringa and J. G. de Vries. J. 
Am. Chem. Soc., 2008, 130, 13508-13509.  
 
4) L. Tang, J. E. van Hylckama Vlieg, J. H. Lutje Spelberg, M. W. Fraaije and D. B. 
Janssen. Enzyme and Microbiol. Tech., 2002, 30, 251-258. 
 
5) J. H. Lutje Spelberg, L. Tang, M. van Gelder, R. M. Kellogg and D. B. Janssen. 
Tetrahedron: Asymmetry, 2002, 13, 1083-1089.  
 
6) M. Ueno, C. Hori, K. Suzawa, M. Ebisawa and Y. Kondo. Eur. J. Org. Chem., 2005, 
1765-1768.  
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This journal is (c) The Royal Society of Chemistry 2010

Supplementary Material (ESI) for Chemical Communications This journal is (c) The Royal Society of Chemistry

One pot ‘click’ reactions: tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition

Halohydrin dehalogenase (HheC) can perform enantioselective azidolysis of aromatic epoxides to 1,2-azido alcohols which are subsequently ligated to alkynes producing chiral hydroxy triazoles in a one-pot procedure with excellent enantiomeric excess.</p

ARTS repository - University of Groningen

University of Groningen

http://stratingh.eldoc.ub.rug.nl/FILES/root/2010/ChemCommCampbellV/2010ChemCommCampbellVerduynSupp.pdf

One pot ‘click’ reactions: tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition

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University of Groningen

University of Groningen

University of Groningen Digital Archive

ARTS repository - University of Groningen