Sequential Two-Step Stereoselective Amination of Allylic Alcohols through the Combination of Laccases and Amine Transaminases

Article abstract of DOI:10.1002/cbic.201900473

A sequential two-step chemoenzymatic methodology for the stereoselective synthesis of (3E)-4-(het)arylbut-3-en-2-amines in a highly selective manner and under mild reaction conditions is described. The approach consists of oxidation of the corresponding racemic alcohol precursors by the use of a catalytic system made up of the laccase from Trametes versicolor and the oxy-radical TEMPO, followed by the asymmetric reductive bio-transamination of the corresponding ketone intermediates. Optimisation of the oxidation reaction, exhaustive amine transaminase screening for the bio-transaminations and the compatibility of the two enzymatic reactions were studied in depth in search of a design of a compatible sequential cascade. This synthetic strategy was successful and the combinations of enzymes displayed a broad substrate scope, with 16 chiral amines being obtained in moderate to good isolated yields (29–75 %) and with excellent enantiomeric excess values (94 to >99 %). Interestingly, both amine enantiomers can be achieved, depending on the selectivity of the amine transaminase employed in the system.

Full text of DOI:10.1002/cbic.201900473

Accepted Article
Title: Sequential Two-Step Stereoselective Amination of Allylic
Alcohols through Combination of Laccases and Amine
Transaminases
Authors: Jesús Albarrán-Velo, Iván Lavandera, and Vicente Gotor-
Fernández
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10.1002/cbic.201900473
ChemBioChem
FULL PAPER
Sequential Two-Step Stereoselective Amination of Allylic
Alcohols through Combination of Laccases and Amine
Transaminases
Jesús Albarrán-Velo,[a] Iván Lavandera*[a] and Vicente Gotor-Fernández*[a]
Abstract: A sequential two-step chemoenzymatic methodology has
been described for the stereoselective synthesis of (3E)-4-
(het)arylbut-3-en-2-amines in a highly selective manner and under
mild reaction conditions. The approach consists in the oxidation of the
corresponding alcohol precursors using the catalytic system
composed by the laccase from Trametes versicolor and the oxy-
radical TEMPO, followed by the asymmetric biotransamination of the
corresponding ketone intermediates. Optimisation of the oxidation
reaction, exhaustive amine transaminase screening for the
biotransaminations and the compatibility of both enzymatic reactions
have been deeply studied, searching for the design of a compatible
sequential cascade. This synthetic strategy has been successfully
achieved, the combination of enzymes displaying a broad substrate
scope as 16 chiral amines have been obtained in moderate to good
isolated yields (29-75% isolated yield) and excellent enantiomeric
excess (94->99). Interestingly, both amine enantiomers can be
achieved depending on the selectivity of the amine transaminase
employed in the system.
Biocatalytic methods have appeared as a sustainable solution for
the synthesis of chiral amines by means of the single action of
several enzyme classes including lipases, amine transaminases
(ATAs), amine oxidases, amine dehydrogenases, imine
reductases or reductive aminases,[21-26 but interestingly in recent
years great devotion has been put towards the synthesis of chiral
amines through chemo-, photo- and multienzymatic
approaches.[27-33 As an example, the selective amination of
racemic sec-alcohols has been described through elegant
cascades via combination of an alcohol dehydrogenase-
catalysed oxidation into ketones with a subsequent bioamination
using ATAs[34,35 or amine dehydrogenases.[36-42 In spite of these
efforts, the biocatalytic synthesis of (3E)-4-arylbut-3-en-2-amines
has received little attention, the activity of a commercial amine
transaminase being low for the biotransamination of (3E)-4-
phenylbut-3-en-2-one towards optically active (3E)-4-phenylbut-
3-en-2-amine (<30%).[43
On the other hand, laccases display great potential for chemical
synthesis but also pulp and paper industry applications.[44-46
These redox enzymes are blue multicopper oxidases able to
catalyse the oxidation of low molecular weight phenols at the
expense of the reduction of molecular oxygen into water through
a four-electron transference.[47 However when attempting the
oxidation of natural substrates, the enzyme requires the use of a
chemical mediator, e.g. 2,2,6,6-tetramethylpiperidinoxyl radical
(TEMPO).[48,49 In this manner, the oxidation of diols,[50 amino
alcohols,[51 profenols,[52 benzylic[53,54 and allylic alcohols[55 has
been fully exploited in our research group, in some cases being
possible the development of sequential multienzymatic
transformations by the proper modification of the reaction
medium. These chemoenzymatic strategies include dynamic
kinetic resolutions[52 and deracemisation of alcohols in
combination with alcohol dehydrogenases,[53 the selective
amination of benzylic alcohols by the use of amine
transaminases,[54 or the redox isomerisation of allylic alcohols
coupling the action of laccases with ene-reductases.[55
Introduction
The chemical preparation of allylic amines has traditionally
attracted great attention,[1,2 due to the presence of this motif in
numerous biologically active and natural products.[3-8 In addition,
their versatility in chemical synthesis has been largely
demonstrated based on their multiple applications for the
preparation
compounds.[9-11 In this context, the stereoselective synthesis of
(3E)-4-arylbut-3-en-2-amine derivatives is particularly
of
valuable
nitrogen-containing
organic
challenging, and it has been described through a series of metal-
catalysed methodologies including kinetic resolutions through
acylation[12 and alkylation processes,[13 or asymmetric synthesis
via Claissen rearrangements,[14 dehydroxybenzotriazolylation,[15
hydrogenation,[16,17 hydroamination,[18 alkenylation reactions,[19
and azidation of allylic esters,[20 among others.
Herein, we propose to extend the applicability of laccases to
produce synthetically challenging optically active allylic amines
via combination of a laccase-mediated oxidation of allylic alcohols
and the subsequent stereoselective biotransamination of the
resulting ketone intermediates using stereocomplementary ATAs
(Scheme 1).
[a]
J. Albarrán-Velo, Dr. I Lavandera,* Dr. V. Gotor-Fernández*
Organic and Inorganic Chemistry Department
University of Oviedo
Avenida Julián Clavería 8, 33006 Oviedo, Spain
E-mail: lavanderaivan@uniovi.es (I.L.) and vicgotfer@uniovi.es
(V.G.-F.)
Supporting information for this article is given via a link at the end of
the document.
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Table 1. Oxidation of 1a (100 mM) with the LTv/TEMPO system in the
presence of different amounts of TEMPO and MTBE as cosolvent.
Entry
TEMPO (mol%)
MTBE (% v/v)
2a (%)[a]
1
2
3
4
5
33
33
33
20
10
----
20
50
50
50
7
8
>99
87
64
Scheme 1. Stereoselective chemoenzymatic amination of allylic alcohols 1a-p
combining the laccase/TEMPO system with an amine transaminase.
[a] Conversion values were measured by GC analyses.
Results and Discussion
Following the methodology reported by Gladkowski and co-
workers,[56
a series of (hetero)aromatic aldehydes were
The optimised reaction conditions found for 1a (entry 3, Table 1)
were then applied to the oxidation of the other allylic alcohols 1b-
p, gratifyingly finding excellent to complete conversions (>98%,
Table 2), independently on the position and the electronic
character of the substitution at the phenyl ring, and also for
various heteroaromatic derivatives such as pyridyl, furyl and
thienyl. Satisfyingly, no by-products were detected in any case,
demonstrating the mildness and selectivity of the
chemoenzymatic system here proposed.
subjected to Claisen-Schmidt condensation with acetone under
basic medium (Scheme S1), obtaining the corresponding
unsaturated ketones 2b-p in good to very high isolated yields (54-
94%). Next, ketones 2a-p were chemically reduced using sodium
borohydride to afford the desired racemic allylic alcohols 1a-p in
46-99% isolated yield.
At this point the study of the individual biooxidation and
biotransamination steps were deeply analysed, trying first to find
suitable conditions for the individual reactions, to later search for
compatible conditions where both enzymes could act in a cascade
or a sequential manner. Initially, (3E)-4-phenylbut-3-en-2-ol (1a)
was selected as model substrate to study the applicability of
commercially available laccase from Trametes versicolor (LTv) in
combination with different amounts of the oxy-radical TEMPO
(10-33 mol%, Table 1). The reactions were carried out under
previously optimised conditions in our research group.[51,53 This
is, in a citrate buffer 50 mM pH 5 with a 100 mM substrate
concentration at 30 ºC and in an open-to-air tube to assure the
oxygen presence. Interestingly, only a 7% conversion into the
ketone 2a was observed with a high TEMPO concentration (33
mol%, entry 1) in the buffer system. Therefore, to favour the
solubility of the substrate,[51-55 MTBE was employed as organic
cosolvent (20-50% v/v, entries 2-5). Due to the low boiling point
of MTBE, it evaporated from the medium after the first three hours
leading to a monophasic system, and a complete conversion was
attained when 50% v/v MTBE and 33 mol% TEMPO were
employed (entry 3), although the use of lower TEMPO loadings
did not allow the reaction get to completion (entries 4 and 5). Even
at prolonged times using 20 mol% of TEMPO (94 and 98%
conversion after 24 and 48 h, respectively) and 10 mol% of
TEMPO (70 and 74% after 24 and 48 h, respectively).
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Table 2. Oxidation of racemic allylic alcohols 1a-p (100 mM) with the
Table 3. Biotransamination of ketone 2a using ATA-024 as biocatalyst and
laccase/TEMPO system using MTBE as cosolvent.
isopropylamine as amine donor.
Entry
1
Alcohol 1a-p
R
Ketone 2a-p (%)[a]
Entry
[2a] (mM)
[PLP] (mM)
T (ºC)
ATA-024
c (%)[b]
(mg/mL)[a]
1a
1b
1c
1d
1e
1f
H
>99
>99
>99
>99
>99
98
1
2
3
4
5
6
7
25
25
25
10
5
0.25
0.5
30
30
30
30
30
30
45
4
4
4
4
4
8
4
45
46
46
56
61
56
63
2
4-OMe
4-Cl
3
1.0
4
4-F
0.25
0.25
0.25
0.25
5
4-Br
6
3-OMe
2-OMe
3-F
10
10
7
1g
1h
1i
>99
99
8
[a] mg of lyophilised ATA-024 per mL of solvent. [b] Conversion values were
measured by GC analyses.
9
2-F
99
10
11
12
13
14
15
16
1j
3-Me
2-pyridyl
3-pyridyl
2-furyl
3-furyl
2-thienyl
3-thienyl
98
1k
1l
99
The use of different cofactor amounts seemed to have not
significant impact in the conversion when 25 mM of ketone 2a was
used (entries 1-3, 45-46% conversion), while higher conversions
were reached at low substrate concentrations (5 and 10 mM,
entries 4 and 5), although there was no change when using more
enzyme loading (entry 6). For practical applications, the best
conditions were found when increasing the temperature to 45 ºC
>99
99
1m
1n
1o
1p
>99
>99
>99
reaching
a promising 63% conversion at 10 mM ketone
concentration (entry 7).
[a] Conversion values were measured by GC analyses.
From this point, exhaustive screenings using ATAs
overexpressed in E. coli cells and later lyophilised
(Chromobacterium
violaceum,[62
Arthrobacter
citreus,[63
Arthrobacter species[64-66 and its evolved mutant ArRmut11[67
)
At this point the biotransamination experiments of the (3E)-4-
(het)arylbut-3-en-2-ones 2a-p were assayed, in order to find
adequate reaction conditions but also suitable amine
transaminases (ATAs) for each substrate to later attempt the
stereoselective amination of the racemic alcohols in a concurrent
approach. PLP-dependent ATAs have been found as ideal
biocatalysts for the transformation of prochiral and racemic
ketones into optically active amines using a molar excess of an
amine donor, generally isopropylamine or alanine.[57-61 For
simplicity, an initial assessment was developed using ketone 2a
and commercially available (R)-selective ATA-024, that is known
to accept isopropylamine as amine donor. Reaction parameters
such as the amount of pyridoxal-5’-phosphate (PLP), ketone
concentration, temperature and ATA loading were considered
(Table 3).
and semipurified commercially available ATAs, also in lyophilised
form, were developed for the sixteen unsaturated ketones
considered in this study, and for a clear understanding all the
results in terms of conversion and enantiomeric excess values
have been included in the Electronic Supporting Information. The
best results are highlighted in Table 4, observing low to very high
conversion values (15-89%) and excellent selectivities (>97% ee).
Remarkably the preparation of both amine enantiomers was
possible depending on the ATA selectivity. Especially (R)-
selective ATA-024, ATA-033 and ATA-415, and (S)-selective
ATA-254, ATA-256 and ATA-260 enzymes proved to be the most
efficient catalysts in these transformations.
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Finally, the two-step sequential process was attempted, so after
the laccase-catalysed oxidation, optimal conditions in terms of pH,
substrate concentration and temperature for the ATAs were
provided in order to make feasible the biotransamination reaction.
Thus, the pH of the solution was adjusted to a value of 7.5 diluting
accordingly the solution until a 10 mM ketone intermediate
concentration, 2.5% DMSO was added to solubilise the reactants
and the temperature was increased up to 45 ºC. In this manner,
the 16 amine enantiomer pairs of 3a-p were obtained in high to
excellent enantiomeric excess values (>93%). For the isolation of
the optically active products, a simple liquid-liquid extraction
protocol was required for allylic amines 3a-j and 3m-p, while for
the pyridyl compounds 3k and 3l a column chromatography was
necessary to isolate them in a pure form (4.1-10.5 mg, 29-81%
isolated yield, Scheme 2). It must be mentioned that when the
scale-up of the processes was achieved, the use of MeCN as
cosolvent was applied as it simplified the isolation processes
through liquid-liquid extraction, providing higher amine yields.
Table 4. Biotransamination of ketones 2a-p using amine transaminases and
isopropylamine as amine donor.
Entry
Ketone
R
Enzyme
c (%)[a]
ee 3a-p (%)[b]
1
2
3
4
2a
2a
2b
2b
H
ATA-033
ATA-256
ATA-025
ATA-254
56
57
42
39
99 (R)
H
>99 (S)
>99 (R)
>99 (S)
4-OMe
4-OMe
5
2c
2c
2d
2d
2e
2e
4-Cl
4-Cl
4-F
ATA-415
ATA-256
ATA-033
ATA-254
ATA-033
ATA-254
45
42
50
49
38
43
>99 (R)
99 (S)
6
7
>99 (R)
>99 (S)
>99 (R)
>99 (S)
8
4-F
Conclusions
9
4-Br
4-Br
10
The design of chemoenzymatic and multienzymatic strategies for
the synthesis of optically active compounds is one of the most
demanding task pursuits nowadays in organic synthesis. Herein,
a sequential two-step synthetic approach has been described for
the synthesis of a series of optically active (3E)-4-(het)arylbut-3-
en-2-amines starting from the corresponding racemic allylic
alcohols. Individual biotransformations were studied and
optimised, finding suitable conditions for the chemoselective
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
2f
3-OMe
3-OMe
2-OMe
2-OMe
3-F
ATA-024
ATA-256
ATA-415
TA-P1-G06
ATA-025
ATA-254
ATA-033
ATA-256
ATA-025
ATA-256
ATA-415
TA-P1-G06
ATA-024
ATA-260
ATA-024
TA-P1-A06
ATA-033
ATA-260
ATA-024
ATA-260
ATA-024
ATA-260
34
38
15
23
56
59
77
76
32
39
59
89
82
76
56
57
56
60
57
58
63
63
>99 (R)
99 (S)
2f
2g
2g
2h
2h
2i
99 (R)
99 (S)
>99 (R)
>99 (S)
>99 (R)
>99 (S)
>99 (R)
>99 (S)
>99 (R)
>99 (S)
>99 (R)
99 (S)
3-F
oxidation
of
(3E)-4-(het)arylbut-3-en-2-ols,
and
the
2-F
biotransamination of the corresponding (3E)-4-arylbut-3-en-2-
ones.
2i
2-F
The catalytic system composed by the laccase from Trametes
versicolor and the chemical mediator TEMPO (33 mol%) has
selectively oxidised 16 racemic allylic alcohols with excellent
conversion (>98%) after 16 h at 30 ºC and using a 100 mM alcohol
concentration, isolating the corresponding ketones with excellent
purity just after a liquid-liquid extraction protocol. After amine
transaminase screening, pairs of enzymes with opposite
selectivity were found to give access to the corresponding
optically active allylic amines in enantiopure form.
A sequential protocol employing both enzymatic methods was
possible by simple changing the pH from 5.0 to 7.5 and diluting
the ketone intermediate concentration to 10 mM, so after addition
of the amine donor (isopropylamine) and the enzyme cofactor
(PLP), a wide panel of optically active (3E)-4-arylbut-3-en-2-
amines were obtained in >94% ee after 24 h at 45 ºC in moderate
to good isolated yields (29-81%) after a simple extraction protocol,
except for pyridyl-derived amines that required an additional
column chromatography purification.
2j
3-Me
2j
3-Me
2k
2k
2l
2-pyridyl
2-pyridyl
3-pyridyl
3-pyridyl
2-furyl
2-furyl
3-furyl
3-furyl
2-thienyl
2-thienyl
3-thienyl
3-thienyl
2l
2m
2m
2n
2n
2o
2o
2p
2p
>99 (R)
>99 (S)
>99 (R)
98 (S)
>99 (R)
99 (S)
>99 (R)
99 (S)
[a] Conversion values were measured by GC analyses. [b] Enantiomeric
excess were measured by GC analyses after derivatisation of the
corresponding amines with acetic anhydride.
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Scheme 2. Stereoselective amination of racemic alcohols 1a-p through a sequential strategy. Isolated yields are shown after a liquid-liquid extraction protocol,
requiring 3k and 3l an additional column chromatography purification.
carried out in a Hewlett Packard 1100 chromatograph UV detector at a 210
nm wavelength for the measurement of enantiomeric excess values.
Experimental Section
Details of analytical methods, retention times and chromatograms have
been included in the Electronic Supporting Information.
Material and methods
Ketone 2a was acquired from Sigma-Aldrich. Laccase from Trametes
versicolor (LTv, 0.66 U/mg) and pyridoxal 5’-phosphate (PLP) were
purchased from Sigma-Aldrich. Codex Transaminase ATA Screening Kit
(ATASK-000250) was purchased from Codexis Inc. The lot numbers of the
more active commercially available ATAs are: D101186 (ATA-024), 0907A
(ATA-025), D15042 (ATA-033), PF282 (ATA-254), 01 (ATA-256), D11125
(ATA-260), D11130 (ATA-415), FER090326 (TA-P1-A06) and D15046
(TA-P1-G06). Lyophilised ATAs overexpressed in E. coli were obtained as
previously reported in the literature.[62-67 All other reagents and solvents
were obtained from Sigma-Aldrich or Acros and used as received.
Sequential reactions were performed in test tubes [(19 x 130 x 3) mm] and
centrifuge tubes [(17 x 118 x 15) mm]. The oxidation step mediated by the
laccase/TEMPO catalytic system was performed in an open-to-air test tube
using magnetic stirring, while for the subsequent transamination step, the
reaction media was transferred to the centrifuge tube, and shaken at 250
rpm and 45 ºC for the required time.
Typical procedure for the synthesis of ketones 2b-p
Ketones 2b-p were synthesised following the procedure described by
Gładkowski et al. for ketone 2a as follows:[56
A solution of the
corresponding aldehyde (3.3 mmol) in acetone (1 mL) and water (0.1 mL)
was placed in a water bath. Then, a 10% NaOH aqueous solution (0.1 mL)
was slowly added. The reaction mixture was stirred overnight at room
temperature and acidified after this time with a HCl 2 M aqueous solution
to pH 2. The product was extracted with CH2Cl2 (3 x 15 mL) and the
combined organic phases dried over anhydrous Na2SO4, filtered and the
solvent evaporated under reduced pressure. The reaction crude was
purified by column chromatography on silica gel (25% EtOAc/hexane
except 83% EtOAc/hexane for pyridyl substrates), yielding the
corresponding ketones 2b-p (54-94% yield).
NMR spectra were recorded on a Bruker AV300 MHz spectrometer. All
chemical shifts () are given in parts per million (ppm) and referenced to
the residual solvent signal as internal standard. IR spectra were recorded
on a Bruker ALPHA spectrophotometer on NaCl pellets. High resolution
mass spectra (HRMS) were obtained in a Bruker Daltonics spectrometer
using the ESI-TOF positive mode. Measurement of the optical rotation was
carried out at 590 nm in a PerkinElmer 241 polarimeter. Thin layer
chromatrographies (TLCs) were conducted with Merck Silica Gel 60 F254
precoated plates and visualised with UV and potassium permanganate
stain. Column chromatographies were performed using Merck Silica Gel
60 (230-400 mesh).
(E)-4-Phenylbut-3-en-2-one (2a) Yellow solid. Rf (25% EtOAc/hexane):
0.58. Mp: 38-40 ºC. IR (NaCl): 3060, 3028, 3003, 1668, 1610, 1359, 1279,
976, 750, 691 cm-1. 1H NMR (300.13 MHz, CDCl3):  2.35 (s, 3H), 6.69 (d,
3JHH = 16.3 Hz, 1H), 7.34-7.39 (m, 3H), 7.46-7.53 (m, 3H) ppm. 13C NMR
(75.5 MHz, CDCl3):  27.5 (CH3), 127.1 (CH), 128.3 (2CH), 129.0 (2CH),
130.5 (CH), 134.4 (C), 143.4 (CH), 198.4 (C) ppm. HRMS (ESI+, m/z):
calcd for (C10H11O)+ (M+H)+ 147.0804, found: 147.0803.
(E)-4-(4-Methoxyphenyl)but-3-en-2-one (2b). Pale yellow solid (512 mg,
88% yield). Rf (25% EtOAc/hexane): 0.44. Mp: 66-68 ºC. IR (NaCl): 3288,
3048, 2941, 2916, 2844, 2774, 2241, 1896, 1683, 1601, 1512, 1251, 989,
854 cm-1. 1H NMR (300.13 MHz, CDCl3):  2.29 (s, 3H), 3.76 (s, 3H), 6.54
Gas chromatrography (GC) analyses were performed on Agilent HP6890
and Agilent HP7820A gas chromatograph apparatus equipped with a FID
detector for the measurement of conversion and enantiomeric excess
values. High performance liquid chromatography (HPLC) analyses were
3
(d, JHH = 16.3 Hz, 1H), 6.82-6.88 (m, 2H), 7.38-7.44 (m, 3H) ppm. 13C
NMR (75.5 MHz, CDCl3):  27.5 (CH3), 55.5 (CH3), 114.6 (2CH), 125.1
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(CH), 127.2 (C), 130.1 (2CH), 143.4 (CH), 161.7 (C), 198.5 (C) ppm.
HRMS (ESI+, m/z): calcd for (C11H13O2)+ (M+H)+ 177.0910, found:
177.0917.
128.1 (CH), 130.5 (d, J = 8.4 Hz, CH), 136.7 (d, J = 7.8 Hz, C), 141.7 (d, J
= 2.7 Hz, CH), 162.9 (d, J = 246.8 Hz, C), 198.0 (C) ppm. 19F NMR (282
MHz, CDCl3):  –112.4 ppm. HRMS (ESI+, m/z): calcd for (C10H10FO)+
(M+H)+ 165.0710, found: 165.0707.
(E)-4-(4-Chlorophenyl)but-3-en-2-one (2c). Pale yellow solid (382 mg,
64% yield). Rf (25% EtOAc/hexane): 0.56. Mp: 56-57 ºC. IR (NaCl): 3286,
3044, 3021, 2972, 2922, 1946, 1661, 1092, 979, 810 cm-1. 1H NMR
(E)-4-(2-Fluorophenyl)but-3-en-2-one (2i). White solid (326 mg, 60%
yield). Rf (25% EtOAc/hexane): 0.59. Mp: 41-42 ºC. IR (NaCl): 3105, 3040,
3
(300.13 MHz, CDCl3):  2.31 (s, 3H), 6.62 (d, JHH = 16.3 Hz, 1H), 7.27-
3012, 2924, 1943, 1816, 1669, 1645, 1487, 1465, 1365, 1228, 1098, 974,
7.32 (m, 2H), 7.36-7.43 (m, 3H) ppm. 13C NMR (75.5 MHz, CDCl3):  27.6
(CH3), 127.4 (CH), 129.2 (2CH), 129.4 (2CH), 132.9 (C), 136.3 (C), 141.8
(CH), 198.0 (C) ppm. HRMS (ESI+, m/z): calcd for (C10H10ClO)+ (M+H)+
181.0415, found: 181.0413.
762 cm-1. 1H NMR (300.13 MHz, CDCl3):  2.31 (s, 3H), 6.70 (d, JHH
=
3
16.5 Hz, 1H), 7.02 (ddd, J = 10.7, J = 8.2, J = 1.1 Hz, 1H), 7.10 (td, J = 7.6,
J = 1.1 Hz, 1H), 7.25-7.33 (m, 1H), 7.48 (td, J = 7.6, J = 1.8 Hz, 1H), 7.59
3
(d, JHH = 16.5 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  27.4 (CH3),
(E)-4-(4-Fluorophenyl)but-3-en-2-one (2d). Pale yellow solid (293 mg,
54% yield). Rf (25% EtOAc/hexane): 0.54. Mp: 31-33 ºC. IR (NaCl): 3072,
3048, 3021, 2923, 2009, 1897, 1668, 1599, 1509, 1231, 977, 818 cm-1. 1H
116.1 (d, J = 21.9 Hz, CH), 122.4 (d, J = 11.4 Hz, C), 124.5 (d, J = 3.6 Hz,
CH), 128.6 (d, J = 3.0 Hz, CH), 129.1 (d, J = 5.4 Hz, CH), 131.9 (d, J = 8.7
Hz, CH), 135.5 (d, J = 3.5 Hz, CH), 161.2 (d, J = 253.9 Hz, C), 198.2 (C)
ppm. 19F NMR (282 MHz, CDCl3):  –114.8 ppm. HRMS (ESI+, m/z): calcd
for (C10H10FO)+ (M+H)+ 165.0710, found: 165.0706.
3
NMR (300.13 MHz, CDCl3):  2.23 (s, 3H), 6.50 (d, JHH = 16.3 Hz, 1H),
6.88-6.99 (m, 2H), 7.29-7.44 (m, 3H). 13C NMR (75.5 MHz, CDCl3):  27.2
(CH3), 115.8 (d, J = 22.0 Hz, 2CH), 126.6 (d, J = 2.2 Hz, CH), 130.0 (d, J
= 8.5 Hz, 2CH), 130.5 (d, J = 3.2 Hz, C), 141.7 (CH), 163.7 (d, J = 251.3
Hz, C), 197.8 (C) ppm. 19F NMR (282 MHz, CDCl3):  –109.2 ppm. HRMS
(ESI+, m/z): calcd for (C10H10FO)+ (M+H)+ 165.0710, found: 165.0696.
(E)-4-(4-Bromophenyl)but-3-en-2-one (2e). White solid (424 mg, 57%
yield). Rf (25% EtOAc/hexane): 0.57. Mp: 77-79 ºC. IR (NaCl): 3079, 3022,
2924, 1912, 1657, 1584, 1262, 978, 806 cm-1. 1H NMR (300.13 MHz,
(E)-4-(m-Tolyl)but-3-en-2-one (2j). Yellow liquid (445 mg, 84% yield). Rf
(25% EtOAc/hexane): 0.61. IR (NaCl): 3022, 2921, 2864, 2735, 1946,
1881, 1819, 1790, 1691, 1667, 1613, 1585, 1359, 1257, 1229, 978, 779,
691, 561 cm-1. 1H NMR (300.13 MHz, CDCl3):  2.03 (s, 3H), 2.04 (s, 3H),
3
3
6.40 (d, JHH = 16.3 Hz, 1H), 6.84-7.04 (m, 4H), 7.17 (d, JHH = 16.3 Hz,
1H) ppm. 13C NMR (75.5 MHz, CDCl3):  20.4 (CH3), 26.5 (CH3), 124.7
(CH), 126.1 (CH), 128.0 (CH), 128.2 (CH), 130.5 (CH), 133.7 (C), 137.6
(C), 142.5 (CH), 196.9 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H13O)+
(M+H)+ 161.0961, found: 161.0944.
3
CDCl3):  2.30 (s, 3H), 6.61 (d, JHH = 16.3 Hz, 1H), 7.28-7.39 (m, 3H),
7.40-7.46 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  27.6 (CH3), 124.6
(C), 127.4 (CH), 129.5 (2CH), 132.1 (2CH), 133.3 (C), 141.8 (CH), 197.9
(C) ppm. HRMS (ESI+, m/z): calcd for (C10H10BrO)+ (M+H)+ 224.9910,
found: 224.9920.
(E)-4-(Pyridin-2-yl)but-3-en-2-one (2k). Pale yellow liquid (340 mg, 70%
yield). Rf (17% hexane/EtOAc): 0.60. IR (NaCl): 3052, 3005, 2921, 1692,
1669, 1620, 1582, 1432, 1359, 1250, 980, 767 cm-1. 1H NMR (300.13 MHz,
CDCl3):  2.38 (s, 3H), 7.11 (d, 3JHH = 16.0 Hz, 1H), 7.26 (ddd, 3JHH = 7.9,
(E)-4-(3-Methoxyphenyl)but-3-en-2-one (2f). Yellow liquid (460 mg, 79%
yield). Rf (25% EtOAc/hexane): 0.48. IR (NaCl): 3370, 3003, 2961, 2942,
2837, 2205, 2072, 2034, 1984, 1933, 1690, 1669, 1359, 1170, 1046, 978,
780, 752, 687 cm-1. 1H NMR (300.13 MHz, CDCl3):  2.38 (s, 3H), 3.83 (s,
3JHH = 4.8, 4JHH = 1.1 Hz. 1H), 7.43-7.54 (m, 2H), 7.70 (apparent td, 3JHH
=
4
3
4
5
7.7, JHH = 1.8 Hz, 1H), 8.63 (ddd, JHH = 4.8, JHH = 1.9, JHH = 0.9 Hz,
1H) ppm. 13C NMR (75.5 MHz, CDCl3):  28.2 (CH3), 124.3 (CH), 124.4
(CH), 130.3 (CH), 136.9 (CH), 142.0 (CH), 150.3 (CH), 153.2 (C), 198.6
(C) ppm. HRMS (ESI+, m/z): calcd for (C9H10NO)+ (M+H)+ 148.0757,
found: 148.0751.
3H), 6.70 (d, 3JHH = 16.3 Hz, 1H), 6.95 (ddd, 3JHH = 8.2, 4JHH = 2.6, 4JHH
1.0 Hz, 1H), 7.06 (apparent t, 4JHH = 2.6 Hz, 1H), 7.13 (d, 3JHH = 7.7 Hz ,1H),
7.31 (apparent t, 3JHH = 7.9 Hz, 1H), 7.47 (d, 3JHH = 16.3 Hz, 1H) ppm. 13
=
C
NMR (75.5 MHz, CDCl3):  26.8 (CH3), 54.6 (CH3), 112.7 (CH), 115.8 (CH),
120.4 (CH), 126.8 (CH), 129.4 (CH), 135.3 (C), 142.7 (CH), 159.4 (C),
197.6 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H13O2)+ (M+H)+ 177.0910,
found: 177.0914.
(E)-4-(Pyridin-3-yl)but-3-en-2-one (2l). Pale yellow solid (383 mg, 79%
yield). Rf (17% hexane/EtOAc): 0.37. Mp: 33-35 ºC. IR (NaCl): 3031, 3006,
2921, 1693, 1672, 1613, 1415, 1360, 1258, 980, 797, 705 cm-1. 1H NMR
(300.13 MHz, CDCl3):  2.37 (s, 3H), 6.74 (d, 3JHH = 16.4 Hz, 1H), 7.31 (dd,
3JHH = 8.0, 3JHH = 4.8 Hz, 1H), 7.47 (d, 3JHH = 16.4 Hz, 1H), 7.83 (apparent
dt, 3JHH = 8.0, 4JHH = 2.0 Hz, 1H), 8.58 (dd, 3JHH = 4.8, 4JHH = 1.6 Hz, 1H),
8.72 (d, 4JHH = 2.3 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  27.8 (CH3),
123.9 (CH), 128.8 (CH), 130.3 (C), 134.3 (CH), 139.5 (CH), 150.0 (CH),
151.3 (CH), 197.8 (C) ppm. HRMS (ESI+, m/z): calcd for (C9H10NO)+
(M+H)+ 148.0757, found: 148.0751.
(E)-4-(2-Methoxyphenyl)but-3-en-2-one (2g). Pale yellow solid (425 mg,
73% yield). Rf (25% EtOAc/hexane): 0.50. Mp: 49-51 ºC. IR (NaCl): 3003,
2940, 2888, 2838, 1666, 1598, 1488, 1466, 1246, 1026, 754 cm-1. 1H NMR
(300.13 MHz, CDCl3):  2.15 (s, 3H), 3.63 (s, 3H), 6.54 (d, 3JHH = 16.5 Hz,
1H), 6.69 (dd, 3JHH = 8.5, 4JHH = 0.8 Hz, 1H), 6.74 (apparent td, 3JHH = 7.4,
3
3
4
4JHH = 0.8 Hz, 1H), 7.14 (ddd, JHH = 8.3, JHH = 7.4, JHH = 1.7 Hz, 1H),
7.30 (dd, 3JHH = 7.8, 4JHH = 1.7 Hz, 1H), 7.68 (d, 3JHH = 16.5 Hz, 1H) ppm.
13C NMR (75.5 MHz, CDCl3):  26.7 (CH3), 54.9 (CH3), 110.7 (CH), 120.3
(CH), 122.7 (C), 127.0 (CH), 127.7 (CH), 131.4 (CH), 138.0 (CH), 157.8
(C), 198.1 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H13O2)+ (M+H)+
177.0910, found: 177.0915.
(E)-4-(Furan-2-yl)but-3-en-2-one (2m). Orange solid (323 mg, 72% yield).
Rf (25% EtOAc/hexane): 0.50. Mp: 35-37 ºC. IR (NaCl): 3144, 3126, 2921,
1687, 1665, 1611, 1359, 1253, 1018, 969, 750 cm-1. 1H NMR (300.13 MHz,
3
3
CDCl3):  2.31 (s, 3H), 6.47 (dd, JHH = 3.4, JHH = 1.8 Hz, 1H), 6.60 (d,
3JHH = 16.0 Hz, 1H), 6.65 (d, JHH = 3.4 Hz, 1H), 7.26 (d, JHH = 15.9 Hz,
1H), 7.49 (d, 3JHH = 1.4 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  28.0
(CH3), 112.7 (CH), 115.8 (CH), 124.4 (CH), 129.5 (CH), 145.1 (CH), 151.0
(C), 197.9 (C) ppm. HRMS (ESI+, m/z): calcd for (C8H9O2)+ (M+H)+
137.0597, found: 137.0596.
3
3
(E)-4-(3-Fluorophenyl)but-3-en-2-one (2h). Pale yellow oil (309 mg, 57%
yield). Rf (25% EtOAc/hexane): 0.57. IR (NaCl): 3066, 3043, 3006, 2922,
1944, 1873, 1804, 1672, 1615, 1583, 1439, 1360, 1259, 979, 783, 682 cm-
1
1. H NMR (300.13 MHz, CDCl3):  2.31 (s, 3H), 6.63 (d, 3JHH = 16.3 Hz,
1H), 6.97-7.06 (m, 1H), 7.13-7.19 (m, 1H), 7.21-7.34 (m, 2H), 7.39 (d, 3JHH
= 16.3 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  27.6 (CH3), 114.3 (d,
J = 21.8 Hz, CH), 117.2 (d, J = 21.4 Hz, CH), 124.2 (d, J = 2.7 Hz, CH),
(E)-4-(Furan-3-yl)but-3-en-2-one (2n). Brown solid (409 mg, 91% yield).
Rf (25% EtOAc/hexane): 0.45. Mp: 44-45 ºC. IR (NaCl): 3132, 3117, 2926,
1661, 1627, 1361, 1274, 1258, 1160, 1017, 971, 870, 798 cm-1. 1H NMR
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10.1002/cbic.201900473
ChemBioChem
FULL PAPER
15.9, 3JHH = 6.4 Hz, 1H), 6.52 (dd, 3JHH = 15.9, 4JHH = 1.1 Hz, 1H), 7.28 (br
s, 4H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.5 (CH3), 68.9 (CH), 127.8
(2CH), 128.2 (CH), 128.9 (2CH), 133.3 (C), 134.3 (CH), 135.3 (C) ppm.
HRMS (ESI+, m/z): calcd for (C10H11ClNaO)+ (M+Na)+ 205.0391, found:
205.0394.
3
(300.13 MHz, CDCl3):  2.31 (s, 3H), 6.43 (d, JHH = 15.7 Hz, 1H), 6.57-
6.60 (m, 1H), 7.37-7.45 (m, 2H), 7.67 (d, 3JHH = 0.9 Hz, 1H) ppm. 13C NMR
(75.5 MHz, CDCl3):  27.4 (CH3), 107.5 (CH), 122.9 (C), 127.3 (CH), 133.5
(CH), 144.7 (CH), 145.0 (CH), 198.2 (C) ppm. HRMS (ESI+, m/z): calcd for
(C8H9O2)+ (M+H)+ 137.0597, found: 137.0593.
(E)-4-(4-Fluorophenyl)but-3-en-2-ol (1d). White solid (230 mg, 46%
yield). Rf (50% Et2O/hexane): 0.46. Mp: 38-40 ºC. IR (NaCl): 3430, 3071,
2977, 1891, 1601, 1508, 1372, 1227, 968, 857 cm-1. 1H NMR (300.13 MHz,
CDCl3):  1.36 (d, 3JHH = 6.4 Hz, 3H), 1.87 (br s, 1H), 4.43-4.51 (m, 1H),
6.17 (dd, 3JHH = 15.9, 3JHH = 6.3 Hz, 1H), 6.52 (d, 3JHH = 15.9 Hz, 1H), 6.96-
7.03 (m, 2H), 7.29-7.36 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.6
(CH3), 68.9 (CH), 115.6 (d, J = 21.6 Hz, 2CH), 128.1 (d, J = 8.3 Hz, 2CH),
128.3 (CH), 133.0 (d, J = 3.3 Hz, C), 133.4 (d, J = 1.9 Hz, CH), 162.4 (d, J
= 246.5 Hz, C) ppm. 19F NMR (282 MHz, CDCl3):  –114.5 ppm. HRMS
(ESI+, m/z): calcd for (C10H11FNaO)+ (M+Na)+ 189.0686, found: 189.0687.
4-(4-Bromophenyl)but-3-en-2-ol (1e). White solid (387 mg, 57% yield).
Rf (50% Et2O/hexane): 0.38. Mp: 46-48 ºC. IR (NaCl): 3385, 2972, 1898,
1655, 1487, 1072, 1009, 805 cm-1. 1H NMR (300.13 MHz, CDCl3):  1.36
(E)-4-(Thiophen-2-yl)but-3-en-2-one (2o). Orange wax (312 mg, 62%
yield). Rf (25% EtOAc/hexane): 0.50. IR (NaCl): 3104, 3085, 2920, 1664,
1595, 1423, 1254, 1200, 1046, 965, 707 cm-1. 1H NMR (300.13 MHz,
3
CDCl3):  2.03 (s, 3H), 6.23 (d, 3JHH = 15.9 Hz, 1H), 6.77 (dd, JHH = 5.1,
3JHH = 3.6 Hz, 1H), 7.01 (d, 3JHH = 3.6 Hz, 1H), 7.13 (d, 3JHH = 5.1 Hz, 1H),
3
7.36 (d, JHH = 15.9 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  26.8
(CH3), 125.1 (CH), 127.7 (CH), 128.4 (CH), 131.0 (CH), 135.0 (CH), 139.1
(C), 196.7 (C) ppm. HRMS (ESI+, m/z): calcd for (C8H8NaOS)+ (M+Na)+
175.0188, found: 175.0190.
(E)-4-(Thiophen-3-yl)but-3-en-2-one (2p). Pale yellow solid (474 mg,
94% yield). Rf (25% EtOAc/hexane): 0.45. Mp: 67-68 ºC. IR (NaCl): 3107,
3008, 2922, 1665, 1636, 1615, 1358, 1265, 1159, 975, 876, 784 cm-1. 1H
(d, 3JHH = 6.4 Hz, 3H), 1.77 (br s, 1H), 4.43-4.52 (m, 1H), 6.24 (dd, 3JHH
=
3
15.9, 3JHH = 6.4 Hz, 1H), 6.50 (d, JHH = 15.9 Hz, 1H), 7.21-7.24 (m, 2H),
7.40-7.45 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.5 (CH3), 68.9
(CH), 121.5 (C), 128.1 (2CH), 128.3 (CH), 131.8 (2CH), 134.4 (CH), 135.8
(C) ppm. HRMS (ESI+, m/z): calcd for (C10H10Br)+ (M-OH)+ 208.9960,
found: 208.9971.
NMR (300.13 MHz, CDCl3):  2.34 (s, 3H), 6.54 (d, JHH = 16.3 Hz, 1H),
3
7.30 (dd, 3JHH = 5.1, 4JHH = 1.1 Hz, 1H), 7.35 (dd, 3JHH = 5.1, 4JHH = 3.4 Hz,
1H), 7.46-7.55 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  27.5 (CH3),
125.3 (CH), 127.1 (CH), 127.2 (CH), 128.7 (CH), 137.0 (CH), 137.8 (C),
198.7 (C) ppm. HRMS (ESI+, m/z): calcd for (C8H8NaOS)+ (M+Na)+
175.0188, found: 175.0181.
(E)-4-(3-Methoxyphenyl)but-3-en-2-ol (1f). Pale yellow liquid (417 mg,
78% yield). Rf (50% Et2O/hexane): 0.37. IR (NaCl): 3425, 2971, 2836,
1926, 1719, 1599, 1288, 1047, 969, 779, 691 cm-1. 1H NMR (300.13 MHz,
CDCl3):  1.36 (d, 3JHH = 6.4 Hz, 3H), 2.87 (br s, 1H), 3.78 (s, 3H), 4.41-
4.50 (m, 1H), 6.25 (dd, 3JHH = 15.9, 3JHH = 6.4 Hz, 1H), 6.51 (d, 3JHH = 15.9
Typical procedure for the synthesis of alcohols 1a-p
Alcohols 1a-j were synthesised following the procedure described by
Gładkowski et al. for alcohol 1a as follows:[56 A solution of NaBH4 (170.2
mg, 4.5 mmol) in water (1 mL) was added dropwise to a stirring solution of
the corresponding (3E)-4-(het)arylbut-3-en-2-one 2a-p (3 mmol) in MeOH
(10 mL) at 0 ºC. The reaction mixture was first stirred for 1 h in an ice bath
and then 2 h at room temperature. Afterwards, hot water was added and
the product was extracted with CH2Cl2 (3 x 15 mL) and the combined
organic phases were washed with brine (5 mL). The organic layer was
dried over anhydrous Na2SO4, filtered and the solvent evaporated under
reduced pressure. The reaction crudes of allylic alcohols were purified by
column chromatography on silica gel, yielding the corresponding alcohols
1a-j (46-99% yield, eluent 50% Et2O/hexane), 1k and 1l (87-91% yield,
eluent 83% EtOAc/hexane) and 1m-p (71-91% yield, eluent 25%
EtOAc/hexane).
Hz, 1H), 6.79 (dd, 3JHH = 6.4, 4JHH = 2.6 Hz, 1H), 6.91 (apparent t, 3JHH
=
2.6, 1H), 6.96 (d, 3JHH = 7.9 Hz, 1H), 7.22 (apparent t, 3JHH = 7.9 Hz, 1H)
ppm. 13C NMR (75.5 MHz, CDCl3):  23.3 (CH3), 55.1 (CH3), 68.6 (CH),
111.7 (CH), 113.2 (CH), 119.1 (CH), 129.0 (CH), 129.5 (CH), 134.0 (CH),
138.2 (C), 159.7 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H14NaO2)+
(M+Na)+ 201.0886, found: 201.0890.
(E)-4-(2-Methoxyphenyl)but-3-en-2-ol (1g). Pale yellow liquid (435 mg,
81% yield). Rf (50% Et2O/hexane): 0.39. IR (NaCl): 3396, 2970, 2837,
1899, 1688, 1598, 1239, 974, 753 cm-1. 1H NMR (300.13 MHz, CDCl3): 
1.41 (d, 3JHH = 6.4 Hz, 3H), 3.01 (br s, 1H), 3.83 (s, 3H), 4.47-4.56 (m, 1H),
6.31 (dd,3JHH = 16.0, 3JHH = 6.4 Hz, 1H), 6.85-6.99 (m, 3H), 7.25 (ddd, 3JHH
3
4
3
= 8.2, JHH = 7.5, JHH = 1.7 Hz, 1H), 7.46 (dd, JHH = 7.5, 4JHH = 1.7 Hz,
1H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.3 (CH3), 55.2 (CH3), 69.0 (CH),
110.7 (CH), 120.5 (CH), 123.9 (CH), 125.7 (C), 126.7 (CH), 128.5 (CH),
134.3 (CH), 156.5 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H14NaO2)+
(M+Na)+ 201.0886, found: 201.0888.
(E)-4-Phenylbut-3-en-2-ol (1a). White solid (445 mg, 99% yield). Rf (50%
Et2O/hexane): 0.44. Mp: 35-36 ºC. IR (NaCl): 3376, 3026, 2973, 2926,
2872, 1949, 1879, 1807, 1751, 1494, 1449, 1141, 1060, 967, 748, 693 cm-
1. 1H NMR (300.13 MHz, CDCl3):  1.38 (d, 3JHH = 6.4 Hz, 3H), 1.81 (br s,
1H), 4.45-4.54 (m, 1H), 6.27 (dd, 3JHH = 15.9, 3JHH = 6.4 Hz, 1H), 6.57 (d,
3JHH = 15.9 Hz, 1H), 7.22-7.27 (m, 1H), 7.30-7.40 (m, 4H) ppm. 13C NMR
(75.5 MHz, CDCl3):  23.5 (CH3), 69.0 (CH3), 126.6 (2CH), 127.8 (CH),
128.7 (2CH), 129.5 (CH), 133.7 (CH), 136.8 (C) ppm. HRMS (ESI+, m/z):
calcd for (C10H12NaO)+ (M+Na)+ 171.0780, found: 171.0785.
(E)-4-(4-Methoxyphenyl)but-3-en-2-ol (1b). White solid (469 mg, 88%
yield). Rf (50% Et2O/hexane): 0.31. Mp: 75-78 ºC. IR (NaCl): 3424, 2956,
2838, 1891, 1513, 1255, 1032, 808 cm-1. 1H NMR (300.13 MHz, CDCl3): 
1.36 (d, 3JHH = 6.4 Hz, 3H), 1.69 (s, 1H), 3.81 (s, 3H), 4.42-4.51 (m, 1H),
6.12 (dd, 3JHH = 15.9, 3JHH = 6.6 Hz, 1H), 6.50 (d, 3JHH = 15.9 Hz, 1H), 6.82-
6.89 (m, 2H), 7.28-7.36 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.6
(CH3), 55.4 (CH3), 69.2 (CH), 114.1 (2CH), 127.8 (2CH), 129.1 (CH), 129.5
(C), 131.5 (CH), 159.4 (C) ppm. HRMS (ESI+, m/z): calcd for
(C11H14NaO2)+ (M+Na)+ 201.0886, found: 201.0875.
(E)-4-(3-Fluorophenyl)but-3-en-2-ol (1h). Pale yellow liquid (354 mg,
71% yield). Rf (50% Et2O/hexane): 0.52. IR (NaCl): 3371, 3075, 3037,
2974, 2928, 1935, 1857, 1585, 1488, 1447, 1265, 1144, 961, 781 cm-1. 1H
NMR (300.13 MHz, CDCl3):  1.41 (d, 3JHH = 6.4 Hz, 3H), 2.49 (br s, 1H),
4.48-4.56 (m, 1H), 6.30 (dd, 3JHH = 15.9, 3JHH = 6.1 Hz, 1H), 6.56 (d, 3JHH
= 15.9 Hz, 1H), 6.93-7.00 (m, 1H), 7.10 (ddd, J = 10.2, J = 2.6, J = 1.6 Hz,
1H), 7.16 (d, J = 7.7 Hz, 1H), 7.27-7.34 (m, 1H) ppm. 13C NMR (75.5 MHz,
CDCl3):  23.5 (CH3), 68.8 (CH), 113.0 (d, J = 21.8 Hz, CH), 114.6 (d, J =
21.4 Hz, CH), 122.5 (d, J = 2.8 Hz, CH), 128.3 (d, J = 2.5 Hz, CH), 130.2
(d, J = 8.4 Hz, CH), 135.0 (CH), 139.2 (d, J = 7.8 Hz, C), 163.2 (d, J =
245.0 Hz, C) ppm. 19F NMR (282 MHz, CDCl3):  –113.5 ppm. HRMS (ESI+,
m/z): calcd for (C10H11FNaO)+ (M+Na)+ 189.0686, found: 189.0695.
(E)-4-(2-Fluorophenyl)but-3-en-2-ol (1i). White wax (380 mg, 76% yield).
Rf (50% Et2O/hexane): 0.56. IR (NaCl): 3431, 2976, 1488, 1457, 1229, 970,
756 cm-1. 1H NMR (300.13 MHz, CDCl3):  1.36 (d, 3JHH = 6.4 Hz, 3H), 3.01
(s, 1H), 4.44-452 (m, 1H), 6.34 (dd, 3JHH = 16.1, 3JHH = 6.3 Hz, 1H), 6.71
(d, 3JHH = 16.1 Hz, 1H), 6.97-7.08 (m, 2H), 7.14-7.21 (m, 1H), 7.41 (td, J =
7.7, J = 1.8 Hz) ppm. 13C NMR (75.5 MHz, CDCl3):  23.3 (CH3), 68.8 (CH),
115.7 (d, J = 22.4 Hz, CH), 121.5 (d, J = 3.7 Hz, CH), 124.1 (d, J = 3.5 Hz,
CH), 124.5 (d, J = 12.2 Hz, C), 127.5 (d, J = 3.7 Hz, CH), 128.7 (d, J = 8.4
(E)-4-(4-Chlorophenyl)but-3-en-2-ol (1c). White solid (351 mg, 64%
yield). Rf (50% Et2O/hexane): 0.48. Mp: 63-65 ºC. IR (NaCl): 3375, 3052,
2975, 1492, 1265, 1092, 739 cm-1. 1H NMR (300.13 MHz, CDCl3):  1.37
(d, 3JHH = 6.4 Hz, 3H), 1.77 (br s, 1H), 4.44-4.52 (m, 1H), 6.23 (dd, 3JHH
=
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10.1002/cbic.201900473
ChemBioChem
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Hz, CH), 136.3 (d, J = 4.5 Hz, CH), 160.3 (d, J = 248.8 Hz, C) ppm. 19F
NMR (282 MHz, CDCl3):  –118.1 ppm. HRMS (ESI+, m/z): calcd for
(C10H11FNaO)+ (M+Na)+ 189.0686, found: 189.0682.
125.1 (CH), 126.2 (CH), 133.6 (CH), 139.4 (C) ppm. HRMS (ESI+, m/z):
calcd for (C8H10NaOS)+ (M+Na)+ 177.0345, found: 177.0333.
(E)-4-(m-Tolyl)but-3-en-2-ol (1j). Pale yellow liquid (414 mg, 85% yield).
Rf (50% Et2O/hexane): 0.46. IR (NaCl): 3405, 2974, 2923, 2733, 1943,
1876, 1606, 1488, 1261, 970, 779, 694 cm-1. 1H NMR (300.13 MHz,
CDCl3):  1.40 (d, 3JHH = 6.4 Hz, 3H), 2.38 (s, 3H), 2.90 (s, 1H), 4.45-4.54
(m, 1H), 6.28 (dd, 3JHH = 15.9, 3JHH = 6.4 Hz, 1H), 6.55 (d, 3JHH = 15.9 Hz,
1H), 7.07-7.13 (m, 1H), 7.18-7.28 (m, 3H). 13C NMR (75.5 MHz, CDCl3): 
21.5 (CH3), 23.5 (CH3), 68.8 (CH), 123.7 (CH), 127.3 (CH), 128.4 (CH),
128.5 (CH), 129.3 (CH), 133.5 (CH), 136.8 (C), 138.1 (C) ppm. HRMS
(ESI+, m/z): calcd for (C11H14NaO)+ (M+Na)+ 185.0937, found: 185.0945.
(E)-4-(Pyridin-2-yl)but-3-en-2-ol (1k). Pale yellow liquid (389 mg, 87%
yield). Rf (17% hexane/EtOAc): 0.40. IR (NaCl): 3375, 2971, 2926, 2869,
1656, 1588, 1565, 1471, 1432, 1367, 1300, 1143, 1062, 999, 854, 766 cm-
1. 1H NMR (300.13 MHz, CDCl3):  1.18 (d, 3JHH = 6.6 Hz, 3H), 4.29-4.41
(m, 1H), 5.18 (br s, 1H), 6.46-6.62 (m, 2H), 6.81-6.90 (m, 1H), 7.04 (dd,
3JHH = 7.9, 4JHH = 1.2 Hz, 1H), 7.35 (apparent td, 3JHH = 7.7, 4JHH = 1.6 Hz,
1H), 8.27 (d, 3JHH = 4.9 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.0
(CH3), 67.2 (CH), 121.1 (CH), 121.7 (CH), 127.6 (CH), 136.4 (CH), 139.1
(CH), 148.7 (CH), 155.2 (C) ppm. HRMS (ESI+, m/z): calcd for (C9H12NO)+
(M+H)+ 150.0913, found: 150.0913.
Typical procedure for the synthesis of amines 3a-j,m-p
Amines 3a-j,m-p were synthesised following the procedure described by
Schenck and Bosnich for amine 3a as follows:[14 Solid NaOH (480 mg, 12
mmol) was added in portions to a solution of the corresponding ketone 2a-
j,m-p (1.2 mmol) and NH2OH.HCl (134 mg, 1.92 mmol) in a mixture of
EtOH (0.96 mL) and water (0.24 mL). The mixture was refluxed overnight,
cooled to room temperature and then acidified with a HCl 6 M aqueous
solution until pH 2. The mixture was extracted with CH2Cl2 (3 x 15 mL) and
the combined organic phases dried over anhydrous Na2SO4, filtered and
the solvent evaporated under reduced pressure, obtaining the
corresponding oxime intermediate, which was further used without
additional purification. Then, zinc dust (393 mg, 6 mmol) was added in
portions to an ice-cooled solution of the so-obtained oxime intermediate in
EtOH (0.8 mL) and glacial acetic acid (0.8 mL). The mixture was allowed
to warm up to room temperature and then gently warmed and stirred on a
steam bath for 2 h. Afterwards, rests of zinc dust were filtered-off and the
solvent evaporated under reduced pressure. The residue was dissolved in
a HCl 6 M aqueous solution (10 mL) and washed with CH2Cl2 (3 x 15 mL).
Then, the aqueous phase was treated with a NaOH 10 M aqueous solution
until pH 12. The resulting aqueous layer was extracted with CH2Cl2 (3 x 15
mL), and the combined organic phases were washed with brine (5 mL),
dried over anhydrous Na2SO4 and filtered. After evaporation of the solvent
under reduced pressure, the corresponding amines 3a-d,f-j,o-p were
obtained with high purity (21-54% yield), except amines 3e, 3m and 3n
that were additionally purified by column chromatography on silica gel (5%
NH3/MeOH, 21-54% yield).
(E)-4-(Pyridin-3-yl)but-3-en-2-ol (1l). Pale yellow liquid (409 mg, 91%
yield). Rf (17% hexane/EtOAc): 0.25. IR (NaCl): 3373, 2970, 2926, 2868,
1654, 1590, 1572, 1480, 1417, 1184, 1143, 1063, 969, 834, 794, 707 cm-
1. 1H NMR (300.13 MHz, CDCl3):  1.18-1.34 (m, 3H), 4.33-4.43 (m, 1H),
5.09 (br s, 1H), 6.13-6.31 (m, 1H), 6.40 (dd, 3JHH = 16.1, 4JHH = 3.3 Hz, 1H),
3
4
7.08 (dt, JHH = 8.3, JHH = 3.2 Hz, 1H), 7.50-7.56 (m, 1H), 8.17-8.44 (m,
2H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.3 (CH3), 67.6 (CH), 123.5 (CH),
124.5 (CH), 132.8 (C), 133.0 (CH), 137.0 (CH), 147.6 (2CH) ppm. HRMS
(ESI+, m/z): calcd for (C9H12NO)+ (M+H)+ 150.0913, found: 150.0914.
(E)-4-(Furan-2-yl)but-3-en-2-ol (1m). Red liquid (369 mg, 89% yield). Rf
(25% EtOAc/hexane): 0.36. IR (NaCl): 3347, 2972, 2927, 2872, 1656,
1563, 1490, 1257, 1150, 1058, 1013, 963, 798, 737 cm-1. 1H NMR (300.13
MHz, CDCl3):  1.30 (d, 3JHH = 6.5 Hz, 3H), 3.20 (br s, 1H), 4.35-4.44 (m,
(E)-4-Phenylbut-3-en-2-amine (3a). Pale yellow oil (92 mg 52% yield). Rf
(5% NH3/MeOH): 0.62. IR (NaCl): 3362, 3287, 2963, 1948, 1878, 1805,
1493, 1449, 1369, 967, 748, 694 cm-1. 1H NMR (300.13 MHz, CDCl3): 
1H), 6.13-6.23 (m, 2H), 6.32 (m, 2H), 7.30 (d, 3JHH = 1.2 Hz, 1H) ppm. 13
C
NMR (75.5 MHz, CDCl3):  23.3 (CH3), 68.1 (CH), 107.8 (CH), 111.2 (CH),
117.5 (CH), 132.4 (CH), 141.8 (CH), 152.5 (C) ppm. HRMS (ESI+, m/z):
calcd for (C8H10NaO2)+ (M+Na)+ 161.0573, found: 161.0586.
3
1.25 (d, JHH = 6.5 Hz, 3H), 1.67 (br s, 2H), 3.61-3.70 (m, 1H), 6.20 (dd,
3JHH = 15.8, 3JHH = 6.6 Hz, 1H), 6.45 (d, 3JHH = 15.8 Hz, 1H), 7.17-7.25 (m,
1H), 7.26-7.39 (m, 4H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.9 (CH3),
49.3 (CH), 126.3 (2CH), 127.3 (CH), 127.8 (CH), 128.6 (2CH), 136.2 (CH),
137.2 (C) ppm. HRMS (ESI+, m/z): calcd for (C10H14N)+ (M+H)+ 148.1121,
found: 148.1119.
(E)-4-(Furan-3-yl)but-3-en-2-ol (1n). Dark orange liquid (361 mg, 87%
yield). Rf (25% EtOAc/hexane): 0.29. IR (NaCl): 3348, 2972, 2928, 2874,
1664, 1508, 1452, 1370, 1160, 1138, 1059, 1023, 965, 848, 779 cm-1. 1H
NMR (300.13 MHz, CDCl3):  1.28 (d, 3JHH = 6.4 Hz, 3H), 3.26 (br s, 1H),
4.31-4.40 (m, 1H), 5.93 (dd, 3JHH = 15.8, 3JHH = 6.3 Hz, 1H), 6.35 (d, 3JHH
= 15.8 Hz, 1H), 6.43-6.48 (s, 1H), 7.30-7.34 (m, 2H) ppm. 13C NMR (75.5
MHz, CDCl3):  23.2 (CH3), 68.4 (CH), 107.5 (CH), 118.8 (CH), 123.6 (C),
133.3 (CH), 140.4 (CH), 143.4 (CH) ppm. HRMS (ESI+, m/z): calcd for
(C8H10NaO2)+ (M+Na)+ 161.0573, found: 161.0570.
(E)-4-(Thiophen-2-yl)but-3-en-2-ol (1o). Brown liquid (423 mg, 91%
yield). Rf (25% EtOAc/hexane): 0.38. IR (NaCl): 3372, 2971, 2925, 2870,
1648, 1449, 1369, 1138, 1058, 957, 853, 695 cm-1. 1H NMR (300.13 MHz,
CDCl3):  1.35 (d, 3JHH = 6.5 Hz, 3H), 3.53 (s, 1H), 4.37-4.46 (m, 1H), 6.11
(dd, 3JHH = 15.7, 3JHH = 6.2 Hz, 1H), 6.68 (d, 3JHH = 15.7 Hz, 1H), 6.90-6.97
(m, 2H), 7.10-7.16 (m, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.2 (CH3),
68.1 (CH), 122.2 (CH), 124.0 (CH), 125.5 (CH), 127.2 (CH), 133.2 (CH),
141.8 (C) ppm. HRMS (ESI+, m/z): calcd for (C8H10NaOS)+ (M+Na)+
177.0345, found: 177.0333.
(E)-4-(4-Methoxyphenyl)but-3-en-2-amine (3b). Pale yellow wax (115
mg, 54% yield). Rf (5% NH3/MeOH): 0.53. IR (NaCl): 3417, 3945, 2964,
2837, 1608, 1512, 1248, 737 cm-1. 1H NMR (300.13 MHz, CDCl3):  1.24
(d, 3JHH = 6.5 Hz, 3H), 2.06 (br s, 2H), 3.63 (m, 1H), 3.79 (s, 3H), 6.06 (dd,
3JHH = 15.9 Hz, 3JHH = 6.8 Hz, 1H), 6.40 (d, 3JHH = 15.9 Hz, 1H), 6.81-6.86
(m, 2H), 7.27-7.31 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.9 (CH3),
49.5 (CH), 55.4 (CH3), 114.1 (2CH), 127.5 (CH), 127.5 (2CH), 130.0 (C),
133.9 (CH), 159.1 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H16NO)+
(M+H)+ 178.1226, found: 178.1231.
(E)-4-(4-Chlorophenyl)but-3-en-2-amine (3c). Yellow wax (92 mg, 42%
yield). Rf (5% NH3/MeOH): 0.64. IR (NaCl): 3356, 3282, 2965, 2925, 1491,
1
3
1092, 808 cm-1. H NMR (300.13 MHz, CDCl3):  1.21 (d, JHH = 6.5 Hz,
(E)-4-(Thiophen-3-yl)but-3-en-2-ol (1p). White solid (328 mg, 71% yield).
Rf (25% EtOAc/hexane): 0.31. Mp: 59-60 ºC. IR (NaCl): 3356, 2971, 2925,
2871, 1656, 1450, 1369, 1159, 1058, 965, 864, 830, 771 cm-1. 1H NMR
(300.13 MHz, CDCl3):  1.36 (d, 3JHH = 6.4 Hz, 3H), 1.75 (s, 1H) 4.40-4.49
3
3
3H), 2.04 (br s, 2H), 3.59-3.68 (m, 1H), 6.14 (dd, JHH = 15.9, JHH = 6.5
3
Hz, 1H), 6.37 (d, JHH = 15.9 Hz, 1H), 7.23 (s, 4H) ppm. 13C NMR (75.5
MHz, CDCl3):  23.8 (CH3), 49.2 (CH), 126.7 (CH), 127.5 (2CH), 128.6
(2CH), 132.8 (C), 135.7 (C), 136.7 (CH) ppm. HRMS (ESI+, m/z): calcd for
(C10H13ClN)+ (M+H)+ 182.0731, found: 182.0739.
3
3
3
(m, 1H), 6.11 (dd, JHH = 15.9, JHH = 6.4 Hz, 1H), 6.58 (dd, JHH = 15.9,
4JHH = 0.6 Hz, 1H), 7.15 (dd, 4JHH = 2.9, 4JHH = 1.2 Hz, 1H), 7.20 (dd, 3JHH
= 5.1, 4JHH = 1.1 Hz, 1H), 7.27 (dd, 3JHH = 5.0, 4JHH = 2.9 Hz, 1H) ppm. 13
C
NMR (75.5 MHz, CDCl3):  23.5 (CH3), 69.0 (CH), 122.3 (CH), 123.8 (CH),
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(E)-4-(4-Fluorophenyl)but-3-en-2-amine (3d). Yellow oil (75 mg, 38%
yield). Rf (5% NH3/MeOH): 0.60. IR (NaCl): 3355, 3287, 2967, 2925, 1928,
1602, 1509, 1226, 1158, 969, 817 cm-1. 1H NMR (300.13 MHz, CDCl3): 
3.61-3.72 (m, 1H), 6.27 (dd, 3JHH = 16.0, 3JHH = 6.7 Hz, 1H), 6.61 (d, 3JHH
= 16.0 Hz, 1H), 6.96-7.10 (m, 2H), 7.13-7.20 (m, 1H), 7.43 (apparent td, J
= 7.7, J = 1.9 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.8 (CH3),
49.8 (CH), 115.8 (d, J = 22.3, CH), 120.6 (d, J = 3.5, CH), 124.2 (d, J = 3.3
Hz, CH), 125.0 (d, J = 12.6 Hz, C), 127.4 (d, J = 3.7 Hz, CH), 128.7 (d, J
= 8.3 Hz, CH), 138.6 (d, J = 4.3 Hz, CH), 160.3 (d, J = 249.1 Hz, C) ppm.
19F NMR (282 MHz, CDCl3):  –118.5 ppm. HRMS (ESI+, m/z): calcd for
(C10H13FN)+ (M+H)+ 166.1027, found: 166.1028.
1.10 (d, 3JHH = 6.5 Hz, 3H), 1.70 (br s, 2H), 3.49 (m, 1H), 5.97 (dd, 3JHH
=
3
15.9, 3JHH = 6.5 Hz, 1H), 6.27 (d, JHH = 15.9 Hz, 1H), 6.80-6.89 (m, 2H),
7.13-7.20 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.5 (CH3), 48.9
(CH), 115.1 (d, J = 21.6 Hz, 2CH), 126.3 (CH), 127.4 (d, J = 7.8 Hz, 2CH),
133.1 (d, J = 3.3 Hz, C), 135.6 (d, J = 2.2 Hz, CH), 161.8 (d, J = 246.1 Hz,
C) ppm. 19F NMR (282 MHz, CDCl3):  –115.0 ppm. HRMS (ESI+, m/z):
calcd for (C10H13FN)+ (M+H)+ 166.1027, found: 166.1029.
(E)-4-(m-Tolyl)but-3-en-2-amine (3j). Yellow oil (81 mg, 42% yield). Rf
(5% NH3/MeOH): 0.58. IR (NaCl): 3354, 3288, 2966, 2922, 1604, 1454,
(E)-4-(4-Bromophenyl)but-3-en-2-amine (3e). Yellow oil (58 mg, 21%
yield). Rf (5% NH3/MeOH): 0.64. IR (NaCl): 3357, 3288, 2962, 2925, 1487,
1359, 1176, 1008, 967, 809 cm-1. 1H NMR (300.13 MHz, CDCl3):  1.24 (d,
3JHH = 6.5 Hz, 3H), 1.61 (br s, 2H), 3.60-3.69 (m, 1H), 6.18 (dd, 3JHH = 15.9,
1373, 968, 778, 695 cm-1. 1H NMR (300.13 MHz, CDCl3):  1.25 (d, 3JHH
=
6.5 Hz, 3H), 1.79 (br s, 2H), 2.34 (s, 3H), 3.61-3.70 (m, 1H), 6.19 (dd, 3JHH
= 15.9, 3JHH = 6.7 Hz, 1H), 6.43 (dd, 3JHH = 15.9, 4JHH = 1.2 Hz, 1H), 6.99-
7.23 (m, 4H) ppm. 13C NMR (75.5 MHz, CDCl3):  21.5 (CH3), 23.9 (CH3),
49.4 (CH), 123.5 (CH), 127.0 (CH), 128.0 (CH), 128.1 (CH), 128.5 (CH),
136.0 (CH), 137.2 (C), 138.1 (C) ppm. HRMS (ESI+, m/z): calcd for
(C11H16N)+ (M+H)+ 162.1277, found: 162.1278.
3
3JHH = 6.5 Hz, 1H), 6.39 (d, JHH = 15.9 Hz, 1H), 7.19-7.23 (m, 2H), 7.38-
7.43 (m, 2H) ppm. 13C NMR (75.5 MHz, CDCl3):  24.0 (CH3), 49.3 (CH),
121.0 (C), 126.8 (CH), 127.9 (2CH), 131.7 (2CH), 136.3 (C), 137.1 (CH)
ppm. HRMS (ESI+, m/z): calcd for (C10H13BrN)+ (M+H)+ 226.0226, found:
226.0221.
(E)-4-(Furan-2-yl)but-3-en-2-amine (3m). Yellow oil (64 mg, 39% yield).
Rf (5% NH3/MeOH): 0.61. IR (NaCl): 3354, 3287, 2966, 2927, 2870, 1651,
1594, 1453, 1374, 1255, 1012, 964, 926, 884, 800, 735 cm-1. 1H NMR
(300.13 MHz, CDCl3):  1.19 (d, 3JHH = 6.5 Hz, 3H), 1.55 (br s, 2H), 3.53-
(E)-4-(3-Methoxyphenyl)but-3-en-2-amine (3f). Yellow oil (94 mg, 44%
yield). Rf (5% NH3/MeOH): 0.58. IR (NaCl): 3358, 3290, 2962, 2835, 1598,
1464, 1156, 1047, 970, 779, 691 cm-1. 1H NMR (300.13 MHz, CDCl3): 
1.21 (d, 3JHH = 6.5 Hz, 3H), 1.97 (br s, 2H), 3.62 (m, 1H), 3.76 (s, 3H), 6.16
(dd, 3JHH = 15.9, 3JHH = 6.6 Hz, 1H), 6.39 (d, 3JHH = 15.9 Hz, 1H), 6.74 (ddd,
3JHH = 8.2, 4JHH = 2.6, 4JHH = 1.0 Hz, 1H), 6.88 (apparent t, 4JHH = 2.6 Hz,
1H), 6.93 (d, 3JHH = 7.8 Hz, 1H), 7.18 (apparent t, 3JHH = 7.8 Hz, 1H) ppm.
13C NMR (75.5 MHz, CDCl3):  23.7 (CH3), 49.2 (CH), 55.1 (CH3), 111.5
(CH), 112.9 (CH), 118.9 (CH), 127.7 (CH), 129.5 (CH), 136.3 (CH), 138.6
(C), 159.7 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H16NO)+ (M+H)+
178.1226, found: 178.1224.
3
3.62 (m, 1H), 6.08-6.18 (m, 2H), 6.26 (d, JHH = 16.0 Hz, 1H), 6.31 (dd,
3JHH = 3.3, 3JHH = 1.9 Hz, 1H), 7.29 (d, 3JHH = 1.8 Hz, 1H) ppm. 13C NMR
(75.5 MHz, CDCl3):  23.9 (CH3), 49.0 (CH), 107.2 (CH), 111.2 (CH), 116.4
(CH), 135.1 (CH), 141.6 (CH), 152.8 (C) ppm. HRMS (ESI+, m/z): calcd for
(C8H12NO)+ (M+H)+ 138.0913, found: 138.0910.
(E)-4-(Furan-3-yl)but-3-en-2-amine (3n). Yellow oil (68 mg, 41% yield).
Rf (5% NH3/MeOH): 0.52. IR (NaCl): 3411, 3405, 2970, 2929, 2872, 1658,
1508, 1452, 1374, 1160, 1073, 1023, 967, 871, 782, 731, 596 cm-1. 1H
NMR (300.13 MHz, CDCl3):  1.21 (d, 3JHH = 6.5 Hz, 3H), 1.55 (br s, 2H),
3.56-3.65 (m, 1H), 5.93 (dd, 3JHH = 15.8, 3JHH = 6.6 Hz, 1H), 6.32 (d, 3JHH
= 15.8 Hz, 1H), 6.50 (d, 3JHH = 1.7 Hz, 1H), 7.35 (m, 1H), 7.37 (s, 1H) ppm.
13C NMR (75.5 MHz, CDCl3):  24.0 (CH3), 49.3 (CH), 107.7 (CH), 117.6
(CH), 124.1 (C), 136.0 (CH), 140.2 (CH), 143.6 (CH) ppm. HRMS (ESI+,
m/z): calcd for (C8H12NO)+ (M+H)+ 138.0913, found: 138.0915.
(E)-4-(2-Methoxyphenyl)but-3-en-2-amine (3g). Brown oil (92 mg, 43%
yield). Rf (5% NH3/MeOH): 0.54. IR (NaCl): 3357, 3289, 2962, 2837, 1935,
1899, 1798, 1597, 1489, 1243, 1028, 975, 752 cm-1. 1H NMR (300.13 MHz,
CDCl3):  1.23 (d, 3JHH = 6.5 Hz, 3H), 3.59-3.67 (m, 1H), 3.81 (s, 3H), 6.19
(dd, 3JHH = 16.0, 3JHH = 6.8 Hz, 1H), 6.74-6.93 (m, 3H), 7.18 (ddd, 3JHH
=
9.1, 3JHH = 7.5, 4JHH = 1.7 Hz, 1H), 7.42 (dd, 3JHH = 7.5, 4JHH = 1.7 Hz, 1H)
ppm. 13C NMR (75.5 MHz, CDCl3):  23.8 (CH3), 49.5 (CH), 55.4 (CH3),
110.7 (CH), 120.6 (CH), 122.4 (CH), 126.1 (C), 126.6 (CH), 128.3 (CH),
137.0 (CH), 156.5 (C) ppm. HRMS (ESI+, m/z): calcd for (C11H16NO)+
(M+H)+ 178.1226, found: 178.1222.
(E)-4-(Thiophen-2-yl)but-3-en-2-amine (3o). Yellow oil (73 mg, 40%
yield). Rf (5% NH3/MeOH): 0.70. IR (NaCl): 3356, 3289, 2959, 2925, 2855,
1650, 1594, 1454, 1376, 957, 853, 810, 696 cm-1. 1H NMR (300.13 MHz,
CDCl3):  1.24 (d, 3JHH = 6.6 Hz, 3H), 1.58 (br s, 2H), 3.58-3.67 (m, 1H),
6.06 (dd, 3JHH = 15.7, 3JHH = 6.6 Hz, 1H), 6.60 (d, 3JHH = 15.7 Hz, 1H), 6.88-
6.97 (m, 2H), 7.12 (d, 3JHH = 4.9 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):
 23.9 (CH3), 49.2 (CH), 121.3 (CH), 123.9 (CH), 125.3 (CH), 127.4 (CH),
136.1 (CH), 142.5 (C) ppm. HRMS (ESI+, m/z): calcd for (C8H12NS)+
(M+H)+ 154.0685, found: 154.0684.
(E)-4-(3-Fluorophenyl)but-3-en-2-amine (3h). Yellow oil (44 mg, 22%
yield). Rf (5% NH3/MeOH): 0.61. IR (NaCl): 3351, 3276, 2961, 2925, 2856,
1936, 1858, 1586, 1488, 1448, 1265, 1142, 969, 783 cm-1. 1H NMR
(300.13 MHz, CDCl3):  1.16 (d, 3JHH = 6.5 Hz, 3H), 1.55 (br s, 2H), 3.52-
3.61 (m, 1H), 6.12 (dd, 3JHH = 15.9, 3JHH = 6.5 Hz, 1H), 6.33 (d, 3JHH = 15.9
Hz, 1H), 6.81 (apparent tdd, J = 8.3, J = 2.6, J = 1.0 Hz, 1H), 6.97 (dt, J =
(E)-4-(Thiophen-3-yl)but-3-en-2-amine (3p). Yellow oil (63 mg, 34%
yield). Rf (5% NH3/MeOH): 0.60. IR (NaCl): 3405, 3392, 2965, 2925, 2868,
1649, 1451, 1372, 1261, 1084, 966, 773 cm-1. 1H NMR (300.13 MHz,
CDCl3):  1.19 (d, 3JHH = 6.5 Hz, 3H), 1.44 (br s, 2H), 3.53-3.62 (m, 1H),
6.02 (dd, 3JHH = 15.9, 3JHH = 6.7 Hz, 1H), 6.43 (dd, 3JHH = 15.9, 4JHH = 0.5
Hz, 1H), 7.06 (dd, 4JHH = 3.0, 4JHH = 1.3 Hz, 1H), 7.16 (dd, 3JHH = 5.0, 4JHH
= 1.2 Hz, 1H), 7.21 (dd, 3JHH = 5.1, 4JHH = 2.9 Hz, 1H) ppm. 13C NMR (75.5
MHz, CDCl3):  23.9 (CH3), 49.2 (CH), 121.4 (CH), 122.0 (CH), 125.0 (CH),
125.9 (CH), 136.1 (CH), 139.7 (C) ppm. HRMS (ESI+, m/z): calcd for
(C8H12NS)+ (M+H)+ 154.0685, found: 154.0683.
10.3, J = 2.2 Hz, 1H), 7.03 (d, J = 7.7 Hz, 1H), 7.12-7.19 (m, 1H) ppm. 13
C
NMR (75.5 MHz, CDCl3):  23.9 (CH3), 49.2 (CH), 112.7 (d, J = 21.8 Hz,
CH), 114.0 (d, J = 21.4 Hz, CH), 122.2 (d, J = 2.7 Hz, CH), 126.8 (d, J =
2.5 Hz, CH), 130.0 (d, J = 8.5 Hz, CH), 137.6 (CH), 139.7 (d, J = 7.8 Hz,
C), 163.1 (d, J = 245.2 Hz, C) ppm. 19F NMR (282 MHz, CDCl3):  –113.6
ppm. HRMS (ESI+, m/z): calcd for (C10H13FN)+ (M+H)+ 166.1027, found:
166.1014.
(E)-4-(2-Fluorophenyl)but-3-en-2-amine (3i). Pale yellow wax (52 mg,
26% yield). Rf (5% NH3/MeOH): 0.64. IR (NaCl): 3356, 3269, 2963, 2925,
2855, 1946, 1912, 1799, 1581, 1488, 1455, 1375, 1229, 970, 755 cm-1. 1H
NMR (300.13 MHz, CDCl3):  1.25 (d, 3JHH = 6.5 Hz, 3H), 1.61 (br s, 2H),
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Typical procedure for the synthesis of amines 3k and 3l[68
pH 7.5 (485 L) containing PLP (1 mM) and isopropylamine (1.0 M) and
the corresponding commercially available ATA (2 mg) were added. The
reaction was shaken at 45 ºC and 250 rpm for 24 h and then stopped by
the addition of a NaOH 10 M aqueous solution (200 L). The mixture was
extracted with EtOAc (500 L) and the organic layer was separated by
centrifugation (2 min, 13,000 rpm). This extraction and centrifugation
protocol was performed twice, and the organic layers were combined and
dried over Na2SO4. Conversion and enantiomeric excess values were
determined by GC (see Tables 3, 4 and others in the Supporting
Information file).
An aqueous solution of conc. sulfuric acid (490 mg, 5 mmol) in dry
acetonitrile (2 mL) was added to a stirred solution of the corresponding
alcohol 1k or 1l (1 mmol) and Na2SO4 (142 mg, 1 mmol) in dry acetonitrile
(3.1 mL) at 0 ºC. The mixture was allowed to reach room temperature, and
the stirring was continued for 24 h. The mixture was concentrated under
reduced pressure, and then cold water was added and the mixture
extracted with diethyl ether (3 x 15 mL). The combined organic layers were
dried over anhydrous Na2SO4 and filtered. After evaporation of the solvent
under reduced pressure, the corresponding acetamides (1 mmol) were
dissolved in a 6 M HCl aqueous solution (5.7 mL) and heated at 80 ºC for
16 h. The resulting solution was basified by addition of a 4 M NaOH
aqueous solution to pH 10 and extracted with diethyl ether (3 x 15 mL).
The combined organic layers were dried over anhydrous Na2SO4 and
filtered. After evaporation of the solvent under reduced pressure, the
corresponding amines 3k and 3l were obtained with high purity in 47 and
58% yield, respectively.
Typical procedure for the sequential two-step synthesis of
enantioenriched amines 3a-p from racemic alcohols 1a-p
In an open-to-air test tube, TEMPO (4.1 mg, 33 mol%) was added to a
solution of the corresponding racemic alcohol 1a-p (0.08 mmol, 100 mM)
in a biphasic mixture of an oxygen-saturated citrate buffer 50 mM pH 5 and
MTBE (50% v/v, for a total volume of 800 L). The reaction mixture was
stirred for a few minutes to dissolve all the reagents, and then the laccase
from Trametes versicolor (7 mg, 4.6 U) was added. The reaction was
stirred for 16 h at 30 ºC, observing the complete evaporation of MTBE
along this time. This fact led to a volume reduction from the initial 800 L
to 400 L, and as a consequence, the substrate concentration increased
from the initial 100 mM to approximately 200 mM. The resulting reaction
crude containing the ketone intermediate 2a-p was transferred to a 15 mL
centrifuge tube, and then DMSO (0.2 mL), phosphate buffer 100 mM pH
7.6 (7.4 mL) containing isopropylamine (1.08 M), and PLP (2 mg) were
added, leading to a concentration approximately of 10 mM for the substrate,
1 M for isopropylamine, 1 mM for PLP and 2.5% v/v of DMSO. At the same
time, the addition of this concentrated buffer to the reaction media, caused
an increase in the pH from an initial value of 5 to approximately 7.5,
therefore, further pH adjustment was not required for the
biotransamination reaction. Finally, the corresponding commercially
available amine transaminase (24 mg) was added. The centrifuge tube
was closed and the reaction shaken at 45 ºC and 250 rpm for 24 h. After
this time, the reaction was stopped by addition of a NaOH 10 M aqueous
solution (3 mL). The mixture was extracted with EtOAc (5 mL) and the
organic layer was separated by centrifugation (3 min, 4,900 rpm). This
extraction and centrifugation protocol was performed twice and, finally, the
organic layers were combined and dried over Na2SO4. Conversion values
into the corresponding enantioenriched amines 3a-p were determined by
GC analyses. Derivatisation of the amines 3a-p as acetamide derivatives
with acetic anhydride in the presence of potassium carbonate was
necessary for the measurement of their enantiomeric excess values.
(E)-4-(Pyridin-2-yl)but-3-en-2-amine (3k). Yellow oil (70 mg, 47% yield).
Rf (5% NH3/MeOH): 0.68. IR (NaCl): 3353, 3278, 3005, 2965, 2925, 2869,
1653, 1587, 1564, 1470, 1432, 1370, 1300, 1150, 974, 767, 742 cm-1. 1H
NMR (300.13 MHz, CDCl3):  1.07 (d, 3JHH = 6.6 Hz, 3H), 1.64 (br s, 2H),
3.46-3.55 (m, 1H), 6.36 (dd, 3JHH = 15.7, 4JHH = 1.2 Hz, 1H), 6.54 (dd, 3JHH
= 15.8, 3JHH = 6.3 Hz, 1H), 6.90 (ddd, 3JHH = 7.5, 3JHH = 4.9, 4JHH = 1.2 Hz,
3
4
1H), 7.07 (apparent dt, JHH = 7.9, JHH = 1.1 Hz, 1H), 7.40 (apparent td,
3JHH = 7.7, 4JHH = 1.8 Hz, 1H), 8.34 (ddd, 3JHH = 4.9, 4JHH = 1.9, 5JHH = 1.0
Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.4 (CH3), 48.7 (CH), 121.1
(CH), 121.6 (CH), 127.3 (CH), 136.2 (CH), 140.5 (CH), 149.1 (CH), 155.3
(C) ppm. HRMS (ESI+, m/z): calcd for (C9H13N2)+ (M+H)+ 149.1073, found:
149.1076.
(E)-4-(Pyridin-3-yl)but-3-en-2-amine (3l). Yellow oil (86 mg, 58% yield).
Rf (5% NH3/MeOH): 0.62. IR (NaCl): 3351, 3275, 3029, 2967, 2926, 2869,
1663, 1587, 1570, 1480, 1453, 1416, 1371, 1024, 969, 847, 828, 709 cm-
1. 1H NMR (300.13 MHz, CDCl3):  1.12 (d, 3JHH = 6.6 Hz, 3H), 1.46 (br s,
2H), 3.50-3.59 (m, 1H), 6.15 (dd, 3JHH = 16.0, 3JHH = 6.3 Hz, 1H), 6.31 (d,
3JHH = 16.0 Hz, 1H), 7.08 (dd, 3JHH = 8.0, 3JHH = 4.8 Hz, 1H), 7.54 (apparent
dt, 3JHH = 8.0, 4JHH = 1.9 Hz, 1H), 8.29 (dd, 3JHH = 4.8, 4JHH = 1.6 Hz, 1H),
8.44 (d, 4JHH = 2.1 Hz, 1H) ppm. 13C NMR (75.5 MHz, CDCl3):  23.7 (CH3),
49.0 (CH), 123.3 (CH), 124.0 (CH), 132.5 (CH), 132.6 (C), 138.4 (CH),
148.0 (CH), 148.1 (CH) ppm. HRMS (ESI+, m/z): calcd for (C9H13N2)+
(M+H)+ 149.1073, found: 149.1076.
Semi-preparative sequential two-step bioamination of alcohols 1a, b,
g and o
General procedure for the laccase-catalysed oxidation of alcohols
1a-p
In an open-to-air test tube, TEMPO (8.2 mg, 33 mol%) was added to a
solution of the corresponding racemic alcohol 1a, b, g or o (0.16 mmol,
100 mM) in a biphasic mixture of an oxygen-saturated citrate buffer 50 mM
pH 5 and MTBE (50% v/v, for a total volume of 1.6 mL). The reaction
mixture was stirred for a few minutes to dissolve all the reagents, and then
the laccase from Trametes versicolor (14 mg, 9.2 U) was added. The
reaction was stirred for 16 h at 30 ºC, observing the complete evaporation
of MTBE along this time. This fact led to a volume reduction from the initial
1.6 mL to 800 L, and as a consequence, the substrate concentration
increased from the initial 100 mM to approximately 200 mM. The resulting
reaction crude containing the ketone intermediate 2a, b, g or o was
transferred to a 50 mL centrifuge tube, and then acetonitrile (MeCN, 0.4
mL), phosphate buffer 100 mM pH 7.6 (14.8 mL) containing
isopropylamine (1.08 M), and PLP (4 mg) were added, leading to a
concentration approximately of 10 mM for the substrate, 1 M for
isopropylamine, 1 mM for PLP and 2.5% v/v of MeCN. At the same time,
In an open-to-air test tube, TEMPO (4.1 mg, 33 mol%) was added to a
solution of the corresponding racemic alcohol 1a-p (0.08 mmol, 100 mM)
in a biphasic mixture of oxygen-saturated citrate buffer 50 mM pH 5 and
MTBE (50% v/v for a total volume of 800 L). The reaction mixture was
magnetically stirred for a few minutes to dissolve all the reagents and then
the laccase from Trametes versicolor was added (7 mg, 4.6 U), and the
mixture magnetically stirred (150 rpm) for additional 16 h at 30 ºC. After
this time, the product was extracted with EtOAc (2 x 2 mL), the organic
phases combined, dried over Na2SO4, filtered and an aliquot was taken for
the determination of the conversion value by GC analysis (see Tables 1
and 2, >98% conversion into ketones 2a-p).
General procedure for the biotransamination of ketones 2a-p
In an Eppendorf vial, the corresponding ketone 2a-p (5 µmol, 10 mM) was
dissolved in DMSO (2.5% v/v, 12 L). Then, a phosphate buffer 100 mM
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10.1002/cbic.201900473
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the addition of this concentrated buffer to the reaction media, caused an
increase in the pH from an initial value of 5 to approximately 7.5, therefore,
further pH adjustment was not required for the biotransamination reaction.
Finally, the corresponding commercially available amine transaminase (48
mg) was added. The centrifuge tube was closed and the reaction shaken
at 45 ºC and 250 rpm for 24 h. After this time, the reaction was stopped by
addition of a NaOH 10 M aqueous solution (6 mL). The mixture was
extracted with EtOAc (10 mL) and the organic layer was separated by
centrifugation (3 min, 4,900 rpm). This extraction and centrifugation
protocol was performed twice and, finally, the organic layers were
combined and dried over Na2SO4. Conversion values into the
corresponding enantioenriched amines 3a, b, g or o were determined by
GC analyses. Optical rotation of enantiopure amine 3a was determined to
confirm the amine absolute configuration: (R)-3a: []D20= +21.5 (c= 1.0,
CHCl3, >99% ee). Lit: []D20= +25.8 (c= 1.16, CHCl3, >99% ee).[15 Then,
the optical rotation values of novel optically active amines 3b, 3g and 3o
were also calculated: (S)-3b: []D20= –34.6 (c= 1.0, CHCl3, >99% ee); (S)-
3g: []D20= –23.5 (c= 1.0, CHCl3, 99% ee); (R)-3o: []D20= +20.8 (c= 1.0,
CHCl3, >99% ee). Derivatisation of these amines as acetamide derivatives
with acetic anhydride in the presence of potassium carbonate was
necessary for the measurement of their enantiomeric excess values, and
the elution times were compared with those previously described[17 to
assign the absolute configurations of the allylic amines obtained by this
enzymatic approach.
[15] A. R. Katritzky, D. Cheng, J. Li, J. Org. Chem. 1998, 63, 3438-3444.
[16] K. Xu, Y.-H. Wang, V. Khakyzadeh, B. Breit, Chem. Sci. 2016, 7, 3313-
3316.
[17] T.-L. Liu, C.-J. Wang, X. Zhang, Angew. Chem. Int. Ed. 2013, 52, 8416-
8419; Angew. Chem. 2013, 125, 8574-8577.
[18] E. Selva, Y. Sempere, D. Ruiz-Martínez, Ó. Pablo, D. Guijarro, J. Org.
Chem. 2017, 82, 13693-13699.
[19] X.-W. Qian, Z.-J. Xue, Q. Zhao, Z. Cui, Y.-J. Chen, C.-G. Feng, G.-Q. Lin,
Org. Lett. 2017, 19, 5601-5604.
[20] S.-I. Murahashi, Y. Taniguchi, Y. Imada, Y. Tanigawa, J. Org. Chem.
1989, 54, 3292-3303.
[21] M. Höhne, U. T. Bornscheuer, ChemCatChem 2009, 1, 42-51.
[22] V. Gotor-Fernández, V. Gotor, Curr. Opin. Drug Discov. Dev. 2009, 12,
784-797.
[23] Chiral Amine Synthesis: Methods, Developments and Applications, (Ed.:
T. C. Nugent), Wiley-VCH, Weinheim, 2010.
[24] D. Ghislieri, N. J. Turner, Top. Catal. 2014, 57, 284-300.
[25] G. Grogan, Curr. Opin. Chem. Biol. 2018, 43, 15-22.
[26] M D. Patil, G. Grogan, A. Bommarius, H. Yun, ACS Catal. 2018, 8,
10985-11015.
[27] R. C. Simon, N. Richter, E. Busto, W. Kroutil, ACS Catal. 2014, 4, 129-
143.
[28] V. Köhler, N. J. Turner, Chem. Commun. 2015, 51, 450-464.
[29] J. Muschiol, C. Peters, N. Oberleitner, M. D. Mihovilovic, U. T.
Bornscheuer, F. Rudroff, Chem. Commun. 2015, 51, 5798-5811.
[30] M. Hönig, P. Sondermann, N. J. Turner, E. M. Carreira, Angew. Chem.
Int. Ed. 2017, 56, 8942-8973; Angew. Chem. 2017, 129, 9068-9100.
[31] S. Schmidt, K. Castiglione, R. Kourist, Chem. Eur. J. 2018, 24, 1755-
1768.
Acknowledgements
Financial support from the Spanish Ministry of Economy and
Competitiveness (MEC, Project CTQ2016-75752-R) and the
Asturian regional government (FC-GRUPIN-IDI/2018/000181)
are gratefully acknowledged. J.A.-V. also thanks the Asturian
regional government for a predoctoral fellowship inside the
Severo Ochoa programme. Prof. Wolfgang Kroutil (University of
Graz, Austria) is acknowledged for the donation of overexpressed
amine transaminases.
[32] J. H. Schrittwieser, S. Velikogne, M. Hall, W. Kroutil, Chem. Rev. 2018,
118, 270-348.
[33] W. Zhang, E. Fernández-Fueyo, Y. Ni, M. van Schie, J. Gacs, R. Renirie,
R. Wever, F. G. Mutti, D. Rother, M. Alcalde, F. Hollmann, Nat. Catal.
2018, 1, 55-62.
[34] K. Tauber, M. Fuchs, J. H. Sattler, J. Pitzer, D. Pressnitz, D. Koszelewski,
K. Faber, J. Pfeffer, T. Haas, W. Kroutil, Chem. Eur. J. 2013, 19, 4030-
4035.
[35] A. Lerchner, S. Achatz, C. Rausch, T. Haas, A. Skerra, ChemCatChem
2013, 5, 3374-3383.
[36] F. G. Mutti, T. Knaus, N. S. Scrutton, M. Breuer, N. J. Turner, Science
2015, 349, 1525-1529.
Keywords: allylic amines • amination of alcohols • amine
transaminases • cascade reactions •laccases
[37] F.-F. Chen, Y.-Y. Liu, G.-W. Zheng, J.-H. Xu, ChemCatChem 2015, 7,
3838-3841.
[1]
[2]
[3]
A. Lauren, P. Mison, A. Nafti, Synthesis 1983, 685-700.
B. M. Trost, T. Zhang, J. D. Sieber, Chem. Sci. 2010, 1, 427-440.
A. Stütz, Angew. Chem. Int. Ed. 1987, 26, 320-328; Angew. Chem. 1987,
99, 323-331.
[38] M. P. Thompson, N. J. Turner, ChemCatChem 2017, 9, 3833-3836.
[39] T. Knaus, L. Cariati, M. F. Masman, F. G. Mutti, Org. Biomol. Chem. 2017,
15, 8313-8325.
[40] W. Böhmer, T. Knaus, F. G. Mutti, ChemCatChem 2018, 10, 731-735.
[41] J. Liu, Z. Li, Biotechnol. Bioeng. 2019, 116, 536-542.
[42] J. A. Houwman, T. Knaus, M. Costa, F. G. Mutti, Green Chem. 2019, 21,
3846-3857.
[4]
[5]
S. Chackalamannil, R. Davies, Org. Lett. 2001, 3, 1427-1429.
D. A. Oliveira, D. G. Pereira, A. M. A. P. Fernandes, S. L. De Castro, A.
R. M. Souza Brito, A. O. De Souza, N. Durán, Parasitol. Res. 2005, 95,
161-166.
[43] A. Gomm, S. Grigoriou, C. Peel, J. Ryan, N. Mujtaba, T. Clarke, E.
Kulcinskaja, E. O'Reilly, Eur. J. Org. Chem. 2018, 5282-5284.
[44] S. Riva, Trends Biotechnol. 2006, 24, 219-226.
[45] S. Witayakran, A. J. Ragauskas, Adv. Synth. Catal. 2009, 351, 1187-
1209.
[6]
[7]
[8]
G. K. Friestad, T. Jiang, A. K. Mathies, Org. Lett. 2007, 9, 777-780.
A. Farwick, G. Helmchen, Org. Lett. 2010, 12, 1108-1111.
W.-Y. Zhang, P. C. Hogan, C.-L. Chen, J. Niu, Z. Wang, D. Lafrance, O.
Gilicky, N. Dunwoody, M. Ronn, Org. Process Res. Dev. 2015, 19, 1784-
1795.
[46] M. D. Cannatelli, A. J. Ragauskas, Chem. Rec. 2017, 17, 122-140.
[47] S. G. Burton, Curr. Org. Chem. 2003, 7, 1317-1331.
[48] M. Mogharabi, M. A. Faramarzi, Adv. Synth. Catal. 2014, 356, 897-927.
[49] I. Gonçalves, C. Silva, A. Cavaco-Paulo, Green Chem. 2015, 17, 1362-
1374.
[9]
B. M. Trost, M. L. Crawley, Chem. Rev. 2003, 103, 2921-2944.
[10] S. Nag, S. Batra, Tetrahedron 2011, 67, 8959-9061.
[11] E. M. Skoda, G. C. Davis, P. Wipf, Org. Process Res. Dev. 2012, 16, 26-
34.
[12] E. G. Klauber, N. Mittal, T. K. Shah, D. Seidel, Org. Lett. 2011, 13, 2464-
2467.
[50] A. Díaz-Rodríguez, I. Lavandera, S. Kanbak-Aksu, R. A. Sheldon, V.
Gotor, V. Gotor-Fernández, Adv. Synth. Catal. 2012, 354, 3405-3408.
[51] A. Díaz-Rodríguez, L. Martínez-Montero, I. Lavandera, V. Gotor, V.
Gotor-Fernández, Adv. Synth. Catal. 2014, 356, 2321-2329.
[13] Y. Wang, Y.-N. Xu, G.-S. Fang, H.-J. Kang, Y. Gu, S.-K. Tian, Org.
Biomol. Chem. 2015, 13, 5367-5371.
[14] T. G. Schenck, B. Bosnich, J. Am. Chem. Soc. 1985, 107, 2058-2066.
For internal use, please do not delete. Submitted_Manuscript
This article is protected by copyright. All rights reserved.

10.1002/cbic.201900473
ChemBioChem
FULL PAPER
[52] A. Díaz-Rodríguez, N. Ríos-Lombardía, J. H. Sattler, I. Lavandera, V.
Gotor-Fernández, W. Kroutil, V. Gotor, Catal. Sci. Technol. 2015, 5,
1443-1446.
[62] U. Kaulman, K. Smithies, M. E. B. Smith, H. C. Hailes, J. M. Ward,
Enzyme Microb. Technol. 2007, 41, 628-637.
[63] S. Pannuri, S. V. Kamat, A. R. M. Garcia, (Cambrex North Brunswick
Inc.), PCT Int. Appl. 2006, WO 2006063336 A2 20060615.
[64] Y. Yamada, A. Iwasaki, N. Kizaki (Kaneka Corporation), EP 0987332 A1,
2000.
[53] K. Kędziora, A. Díaz-Rodríguez, I. Lavandera, V. Gotor-Fernández, V.
Gotor, Green Chem. 2014, 16, 2448-2453.
[54] L. Martínez-Montero, V. Gotor, V. Gotor-Fernández, I. Lavandera, Green
Chem. 2017, 19, 474-480.
[65] A. Iwasaki, Y. Yamada, N. Kizaki, Y. Ikenaka, J. Hasegawa, Appl.
Microbiol. Biotechnol. 2006, 69, 499-505.
[55] L. Martínez-Montero, V. Gotor, V. Gotor-Fernández, I. Lavandera, ACS
Catal. 2018, 8, 2413-2419.
[66] F. G. Mutti, C. S. Fuchs, D. Pressnitz, J. H. Sattler, W. Kroutil, Adv. Synth.
Catal. 2011, 353, 3227-3233.
[56] W. Gładkowski, A. Skrobiszewski, M. Mazur, M. Siepka, A. Pawlak, B.
Obmińska-Mrukowicz, A. Białońska, D. Poradowski, A. Drynda, M.
Urbaniak, Tetrahedron 2013, 69, 10414-10423.
[67] C. K. Savile, J. M. Janey, E. M. Mundorff, J. C. Moore, S. Tam, W. R.
Jarvis, J. C. Colbeck, A. Krebber, F. J. Fleitz, J. Brands, P. N. Devine, G.
W. Huisman, G. J. Georges, Science 2010, 329, 305-309.
[68] F. Messina, M. Botta, F. Corelli, M. P. Schneider, F. Fazio, J. Org. Chem.
1999, 64, 3767-3769.
[57] F. Guo, P. Berglund, Green Chem. 2017, 19, 333-360.
[58] I. Slabu, J. L. Galman, R. C. Lloyd, N. J. Turner, ACS Catal. 2017, 7,
8263-8284.
[59] M. D. Patil, G. Grogan, A. Bommarius, H. Yun, Catalysts 2018, 8, 254.
[60] A. Gomm, E. O’Reilly, Curr. Opin. Chem. Biol. 2018, 43, 106-112.
[61] P. Kelefiotis-Stratidakis, T. Tyrikos-Ergas, I. V. Pavlidis, Org. Biomol.
Chem. 2019, 17, 1634-1642.
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10.1002/cbic.201900473
ChemBioChem
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Jesús Albarrán-Velo, Iván Lavandera,*
Vicente Gotor-Fernández*
Page No. – Page No.
Sequential Two-Step Stereoselective
Amination of Allylic Alcohols
through Combination of Laccases
and Amine
A sequential two-step amination of (3E)-4-(het)arylbut-3-en-2-alcohols has been
described through a sequential cascade. The approach consists in their laccase
Trametes versicolor/TEMPO-mediated oxidation to form the corresponding ketone
intermediates, followed by asymmetric biotransamination using amine
transaminases. Satisfyingly, 16 amine enantiomer pairs were obtained in very high
to excellent stereoselectivity (94->99% ee) and moderate to good isolated yields
(29-75% isolated yield).
For internal use, please do not delete. Submitted_Manuscript
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