Structure-Dependent Nickel-Catalysed Transposition of N -Allylamides to E- or Z-Enamides

Article abstract of DOI:10.1055/s-0036-1588340

The nickel-catalysed transposition of a carbon-carbon double bond of N-allyl and N-homoallyl amides is described. While the transposition of acyclic amides gave very high Z-selectivity of the enamides, corresponding cyclic N-allyl amides led exclusively t

Full text of DOI:10.1055/s-0036-1588340

SYNTHESIS
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© Georg Thieme Verlag Stuttgart · New York
2016, 48, A–K
paper
A
F. Weber et al.
Paper
Synthesis
Structure-Dependent Nickel-Catalysed Transposition of N-Allyl-
amides to E- or Z-Enamides
Felicia Weber
O
O
Philipp S. Steinlandt
Monika Ballmann
Gerhard Hilt*
Ph
N
H
Ph
N
H
Me
nickel catalyst
O
O
Fachbereich Chemie, Philipps-Universität Marburg,
Hans-Meerwein-Straße 4, 35043 Marburg, Germany
hilt@chemie.uni-marburg.de
Me
N
N
Dedicated to Prof. Dieter Enders on the occasion of
his 70th birthday
Received: 10.10.2016
Accepted: 13.10.2016
Published online: 14.11.2016
DOI: 10.1055/s-0036-1588340; Art ID: ss-2016-z0719-op
(Scheme 1).5 These reactions proceed under mild reaction
conditions and even at temperatures as low as –60 °C and
can be used in one-pot reactions such as allylborations or
Hosomi–Sakurai reactions.8 The use of diphenylphosphine
is crucial for the efficient transposition of the alkene moiety
in each substrate and a theoretical explanation of the
mechanism will be published soon.9
Abstract The nickel-catalysed transposition of a carbon–carbon dou-
ble bond of N-allyl and N-homoallyl amides is described. While the
transposition of acyclic amides gave very high Z-selectivity of the
enamides, corresponding cyclic N-allyl amides led exclusively to the E-
configured products. Thereby, we realised a stereodivergent approach
to enamides that is dependent on the structure of the amide substitu-
ents. When homoallylic substrates are used, a temperature-controlled
single transposition to a Z-allylic amide derivative at low temperature or
a double transposition to an E-enamide at elevated temperature could
be achieved.
previous work
Ni(dppp)Cl2, HPPh2
Zn, ZnI2
R
R
CH2Cl2
Me
this work
O
Ni(dppp)Cl2, HPPh2
Zn, ZnI2
O
Key words allyl amides, double bond translocation, enamides, nickel,
stereoselectivity
R
N
R
N
H
CH2Cl2
H
Me
Scheme 1 Overview of previous and current work
The chemistry of enamides is a growing field in organic
synthesis and various applications of this functional group
have been described.1 An atom-economic synthesis of
enamides is the transposition of the terminal carbon–car-
bon double bond of the corresponding allylamides.2 How-
ever, one problem of such a process is the stereocontrol of
the migrating double bond. In the past, such an transposi-
tion has been applied with various transition-metal cata-
lysts, such as ruthenium, rhodium, iron, iridium or nickel-
based systems.3–6 Usually, an E/Z-mixture or the thermody-
namically favoured E-configured enamides were obtained.
The achievement of the corresponding Z-configured enam-
ide through double-bond migration is rarely described and
thus still under-represented.7 Herein, we describe our at-
tempts to control the stereochemistry of the enamide to-
wards the Z-geometry through transposition of the corre-
sponding N-allylamides by using our nickel-based catalyst
system, consisting of a nickel(II) pre-catalyst, Zn, ZnI2, and
diphenylphosphine (HPPh2), which has been applied in the
transposition of terminal alkenes to 2-Z-alkenes in the past
By using our initial nickel catalyst system Ni(dppp)Cl2
(10 mol%),10 ZnI2 (20 mol%), zinc powder (20 mol%), and di-
phenylphosphine (5 mol%) in anhydrous dichloromethane,
complete conversion of the test substrate N-allyl benzamide
(R = Ph) was achieved after 20 h reaction time at –20 °C
with an isolated yield of 70% and an E/Z ratio of 1:4
(Scheme 2). Given that the outcome of the reaction was not
yet satisfactory, we first tried to modify our initial reaction
conditions regarding the nature and amount of the Lewis
acid, which could be the reason for a loss of yield, before
turning our attention to temperature modifications to ob-
tain the best possible Z-selectivity.
The use of only 10 mol% ZnI2 under otherwise un-
changed reaction conditions led to incomplete conversion
(85% after 20 h at –20 °C), whereas in the absence of ZnI2
only 7% conversion was observed. However, the substitu-
tion of ZnI2 towards ZnCl2 (20 mol%) is possible, but a longer
reaction time is encountered because of incomplete con-
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

B
F. Weber et al.
Paper
Synthesis
version of the starting material (80% after 20 h at –20 °C).
The use of other Lewis acids such as BF3·Et2O, AgOTos (no
conversion) or TiCl4 (decomposition of the starting materi-
al) was also unsuccessful. Only the application of AgOAc led
to full conversion after 48 h; however, an inferior amount of
the Z-isomer (E/Z = 1:2) was formed compared with the
amount obtained with ZnI2. All Lewis acids led to compara-
ble or lower isolated yield of the enamide than obtained in
the reaction catalysed by 20 mol% ZnI2. Furthermore, as en-
countered in previous reactions, the HPPh2 proved to be
highly beneficial, because in the absence of this additive no
conversion was observed at all.
Ni(dppp)Cl2 (10 mol%)
HPPh2 (5 mol%)
Zn (20 mol%)
O
O
ZnI2 (20 mol%)
Ph
N
Ph
N
−20 °C, 20 h
CH2Cl2
70%, E/Z = 1:4
H
H
Me
1
2
Scheme 2 Nickel-catalysed transposition of N-allyl amides
To explore the substrate scope for our method, a survey
was undertaken to screen a number of representative sub-
stituents R and reaction conditions; these investigations
identified the highest reactivity, the lowest amount of side
products and the best Z/E ratio in enamides 2. The results of
this investigation are summarised in Table 1.
Table 1 Transposition of N-Allyl Amides According to Scheme 2
Ni(dppp)Cl2 (10 mol%)
HPPh2 (5 mol%)
Zn, ZnI2 (20 mol%)
O
O
R
N
R
N
H
CH2Cl2, T, t
H
Me
1
2
Entry
1
Product of type 2
Temp (°C)
–20
Time (h)
48
Yield (%)
12a
E/Z ratio
O
Me
Me
N
H
ca. 20:80
Me
2a
O
N
2
25
1.5
42
18:82
H
Me
2b
O
3
4
5
–30
83b
–30
64
144
64
60
54
74
8:92
50:50
9:91
N
H
Me
2c
O
N
H
Me
2d
O
N
H
Me
2e
Me
O
N
6
7
25c
25c
168
192
47
70
14:86d
36:64
H
Me
Me
Me
2f
O
N
H
Me
MeO
2g
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

C
F. Weber et al.
Paper
Synthesis
Table 1 (continued)
Entry
Product of type 2
Temp (°C)
Time (h)
39
Yield (%)
66
E/Z ratio
O
N
H
8
9
–20
–25
18
19:81
7:93
Me
Me
Cl
2h
O
N
H
69
45
72
62
63
33
Br
2i
O
N
10
11
22:78
16:84
H
Me
F3C
2j
O
N
5
H
S
Me
2k
O
N
12
13
25/45/80
up to 72e
0
–
Me
Me
2l
O
Me
25
48
64
85:15
F3C
N
H
2m
a Product 2a is volatile and traces of solvent remained in the isolated sample.
b The reaction was carried out in acetonitrile instead of dichloromethane.
c Additional catalyst was added, see experimental section.
d A mixture of rotamers of the Z-isomer was obtained. The Z/E/SM ratio is 79:10:11 (SM = starting material, see experimental section).
e The reaction was carried out in dichloromethane as well as acetonitrile at different temperatures, but no conversion was observed.
Over the course of the investigation, a series of reactions
was performed for each substrate to identify optimised re-
action time and temperature to achieve the goals detailed
above. The use of the simplest alkyl chain in 1a (R = Me) re-
sulted in problems with the isolation of the product 2a be-
cause the product was volatile and the solvent could not be
removed completely. However, the inclusion of a longer ali-
phatic side chain (2b) solved this problem, although the
yield remained relatively low and the reaction temperature
had to be raised to ambient temperature. The benzylic am-
ide 1c was a very reactive substrate that could be isomer-
ised at –30 °C to furnish the product 2c in acceptable yield
and good stereoselectivity. Of similar high reactivity was
the simple benzamide derivative, which led to the forma-
tion of 4e in comparable good yield and E/Z ratio. On the
other hand, the substrates derived from cinnamamide (2d),
a sterically hindered arene (2f) and an electron-donating
arene (2g) required very prolonged reaction times at elevat-
ed temperatures. The addition of more catalyst was neces-
sary to obtain full conversion of the N-allyl amide. Electron-
withdrawing substituents on the arene moiety (2h–j) gave
more reactive amides and acceptable results. The hope that
a weak coordination site, such as the thiophene substituent,
would be beneficial (2k) could not be established. The use
of the CF3-substituted amide 1m resulted in the formation
of the E-isomer 2m as the major product.
We also investigated the use of urethane derivatives as
alternative functional groups to facilitate the reaction
(Scheme 3).
Although the reactivity of substrates 3a–c was accept-
able and a good yield of 79% for 4a was realised, the Z/E ra-
tios of the products 4a–c were inferior to the previously re-
ported benzamide derivatives 1e and 1i. Furthermore, the
desired enecarbamate was sensitive towards the reaction
conditions and the Lewis acid was found to cause further
transformation into side products, such as benzylic alcohol
in the case of enecarbamate 4b, phenylisocyanate and ani-
line, thereby rationalising the moderate yield of 4c.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

D
F. Weber et al.
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Synthesis
Ni(dppp)Br2 (10 mol%)
HPPh2 (5 mol%)
Zn (20 mol%)
O
O
O
O
tBuO
N
Me
tBuO
N
H
3a
X
N
H
ZnI2 (10 mol%)
X
N
Me
4a (−30 °C, 19 h)
5
6
79% (Z/E = 81:19)
CH2Cl2
n
n
O
O
Ni(dppp)Br2 (10 mol%)
HPPh2 (5 mol%)
Zn (20 mol%)
Scheme 4 Nickel-catalysed transposition of cyclic amides and related
BnO
N
BnO
N
H
3b
H
derivatives
Me
ZnI2 (10 mol%)
CH2Cl2
4b (−30 °C, 17 h)
69% (Z/E = 81:19)
O
O
exclusively the E-isomers at ambient temperatures. The re-
activity of oxazolidinone 5b was somewhat higher based on
the lower reaction temperature, but the E-selectivity was
diminished compared with the lactams. To test whether the
nickel catalyst would also be capable of isomerising
branched systems, the racemic substrate 5e was applied
and the desired product 6e was obtained as a 1:2 mixture
of Z- and E-isomers. This result illustrates that the nickel-
catalyst system is capable of converting more hindered
double bond systems as well, but further optimisation
might be needed to realise a highly selective process.
As a summary at this point, we would like to draw at-
tention to the following results (Scheme 5). The nickel-cata-
lysed transposition of 1e into 2e proceeded with the best
results towards the Z-configured product. In contrast, the
corresponding N-methyl derivative 1l failed in the reaction.
Nevertheless, cyclic amide 6a gave the E-configured prod-
uct in outstanding yield and E-selectivity. This interesting,
and somewhat puzzling finding, might be rationalised by
the conformation that the substrate adopted when coordi-
nated to the nickel catalyst during the overall hydrogen-
shift reaction. To test this hypothesis, in silico investigations
will be conducted in the near future to better understand
the catalytic system at work.
Ph
Ph
N
O
N
O
H
H
Me
3c
4c (−20 °C, 48 h)
36% (Z/E = 87:13)
(decomposition)
Scheme 3 Nickel-catalysed transposition of urethanes
Another interesting observation has to be mentioned.
The tertiary N-methyl derivative 1l gave no conversion into
2l. This devastating result of the N-methyl benzamide de-
rivative 1l suggested that a free NH-group is beneficial, if
not crucial, for the nickel-catalysed translocation of double
bonds; we therefore also investigated other cyclic tertiary
N-allyl derivatives (Scheme 4). The results of the nickel-
catalysed reactions are summarised in Table 2.
Table 2 Transposition of Cyclic N-Allyl Amides and Related Derivatives
Entry Product of type 6
Temp
(°C)
Time
(h)
Yield
E/Z ratio
O
1
2
3
25
25
25
24
16
16
98
100:0
N
Me
Me
6a
6b
O
O
O
93
77
94:6
O
N
Ph
Ph
N
H
Ph
Ph
N
H
1e
Me
2e
O
O
O
Ni(dppp)Br2 (10 mol%)
HPPh2 (5 mol%)
Zn (20 mol%)
100:0
N
N
Me
N
ZnI2 (10 mol%)
CH2Cl2
Me
Me
Me
6c
Me
1l
2l
O
O
O
N
N
N
Me
Me
4
5
25
18
72
85
70
100:0
67:33
6a
5a
O
6d
Scheme 5 Comparison between different types of reactivities and se-
lectivities of the nickel-catalysed transposition reactions
O
Me
N
0
Finally, we were interested in establishing whether the
translocation of the carbon–carbon double bond could be
realised along a longer side chain and whether the reaction
temperature could be utilised to differentiate between a
single and a double translocation process, towards the
products 8 and 9, respectively. For this purpose, substrate 7
was applied to the nickel catalyst system at different tem-
O
6e
Cyclic N-allyl systems also seem to be excellent sub-
strates for the nickel-catalysed transposition of double
bonds. Simple lactams (6a/6c) or a phthalimide (6d) gave
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

E
F. Weber et al.
Paper
Synthesis
starting material. In the case of volatile products, the content of sol-
vent residues was evaluated by 1H NMR analysis and considered
when determining the yield. The Z/E ratio of the product was deter-
mined by integration of suitable baseline separated 1H NMR or 19F
NMR signals and comparison with the corresponding peaks in the
GC-MS spectrum.
Ni(dppp)Cl2 (10 mol%)
HPPh2 (5 mol%)
Zn (20 mol%)
O
O
Me
ZnI2 (10 mol%)
O
N
O
N
8
7
−10 °C, 16 h
CH2Cl2
83% Z/E = 84:16
1H and 13C NMR spectra were recorded with either a Bruker AV 300
(300 MHz for 1H NMR, 76 MHz for 13C NMR, and 283 MHz for 19F NMR
spectra) or a Bruker AV 500 (500 MHz for 1H NMR and 126 MHz for
13C NMR spectra). Chemical shifts are reported in parts per million
(ppm) and are referenced to the solvent peak of CDCl3 as the internal
Ni(dppp)Cl2 (10 mol%)
HPPh2 (5 mol%)
Zn (20 mol%)
O
O
O
N
ZnI2 (10 mol%)
O
N
Me
9
7
25 °C, 16 h
CH2Cl2
standard (CHCl3: δ = 7.26 ppm for 1H NMR and δ = 77.16 ppm for 13
C
82% Z/E = 0:100
NMR). IR spectra were recorded with a Bruker IFS 88 (FTIR) spectrom-
eter. ESI-HRMS were recorded with a Finnigan LTQ-FT target coupled
with an Agilent 1100 HPLC at an energy of 70 eV. GC analysis was per-
formed with a Shimadzu GC-2010 Plus series Gas Chromatograph
with a flame-ionisation detector (FID). GC-MS spectra were recorded
with an Agilent 6890 gas chromatograph coupled with a Hewlett
Packard 5973 mass selective detector. Melting points were deter-
mined with a heat table microscope of Kofler.
Scheme 6 Temperature-dependent sequential transposition of N-
homo-allylic oxazolidinone 7
peratures; the best results with respect to selectivity and
yield are shown in Scheme 6.
To our delight, the control of the reaction temperature is
an appropriate tool to direct the nickel-catalysed transposi-
tion of a terminal carbon–carbon double bond towards a Z-
selective single transposition; thus, product 8 was obtained
in good yield and acceptable Z-selectivity (conversion ca.
88%) when a low reaction temperature was maintained.
When the temperature was raised to 25 °C the transposi-
tion proceeded via the primary product 8 towards the ther-
modynamically favoured product 9 in an E-selective reac-
tion in good yield of 81% as a single E-isomer. One has to
keep in mind that a Z/E ratio of 0:100 of 9 is unlikely to be a
thermodynamically controlled process towards the equilib-
rium between the E- and Z-isomer. More likely is a nickel-
induced kinetic process that is highly E-selective to furnish
the observed E-configured product.
In summary, we have shown that a nickel-based catalyst
bearing a HPPh2 ligand is capable of translocating a carbon–
carbon double bond of an N-allyl amide towards a Z-config-
ured enamide in good yields. On the other hand, the same
catalyst led to the translocation of the double bond in lact-
am systems with outstanding results towards the E-enam-
ide. Furthermore, a temperature-controlled single or double
migrationary process could be realised to generate either a
Z-configured allyl amide or an ethyl-substituted enamide in
good to excellent selectivity.
Transposition of N-Allylamides and N-Allylcarbamates; General
Procedure
Under an argon atmosphere, nickel catalyst (10 mol%, 50.0 μmol), zinc
powder (20 mol%), and anhydrous zinc iodide (100 μmol each) were
suspended in either anhydrous dichloromethane (0.3 mL) or anhy-
drous acetonitrile (0.3 mL) in a flame-dried Schlenk tube fitted with a
Teflon screw-cap. The mixture was stirred for 10 min and Ph2PH solu-
tion (0.2 mL, 25.0 μmol, 5 mol%, 0.125 M in dichloromethane or aceto-
nitrile) was added. After stirring for 10 min, the mixture was cooled
to the stated temperature. The N-allylamide or N-allylcarbamate
(0.50 mmol, 1.0 equiv) was then added and the reaction was stirred at
the desired temperature.
The progress of the reaction was monitored by GC-MS analysis. In
case of incomplete conversion of the starting material, additional cat-
alyst was added. By addition of diethyl ether, the reaction was
stopped when no further conversion could be detected. The solution
was directly purified by flash column chromatography on silica gel
(n-pentane/diethyl ether or n-pentane/EtOAc). The E/Z ratio of the
product was determined by integration of suitable baseline-separated
1H NMR signals and by comparison with the corresponding peaks in
the GC-MS spectrum.
(Z)-N-(Prop-1-en-1-yl)acetamide (2a)
[Z: CAS Reg. No. 5202-79-9; E: CAS Reg. No. 5202-80-2]
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–20 °C, N-allylacetamide (50 mg, 0.505 mmol, 1.0 equiv) was added.
The reaction mixture was stirred for 2 d at –20 °C. Workup according
to the general procedure and purification by flash column chroma-
tography (n-pentane/EtOAc, 1:1) afforded a Z/E-mixture of 2a.
Reagents were used as purchased from commercial suppliers without
further purification or were prepared according to reported proce-
dures, if not otherwise stated. All experiments were carried out by
using standard Schlenk techniques under argon atmosphere. THF and
diethyl ether were dried over sodium. Dichloromethane and acetoni-
trile were dried over calcium hydride. All solvents were distilled un-
der nitrogen atmosphere and stored over 4 Å molecular sieves. Flash
chromatography was carried out on Macherey-Nagel Silica 60 (40–
63 μm, 230–400 mesh ASTM). Thin-layer chromatography was car-
ried out on Merck TLC plates (Silica 60, F254 with fluorescence indi-
cator). The determination of yields was carried out gravimetrically.
The stated values are in weight-% relative to the quantities of the
Yield: 6 mg (0.061 mmol, 12%); colourless volatile liquid; Z/E = 80:20.
1H NMR (300 MHz, CDCl3): δ [(Z)-2a] = 6.91 (s, 1 H), 6.74–6.68 (m,
1 H), 4.79 (dq, J = 8.3, 7.1 Hz, 1 H), 2.08 (s, 3 H), 1.61 (dd, J = 7.0,
1.7 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2a] = 5.15–5.08 (m,
1 H), 2.01 (s, 3 H), 1.66 (dd, J = 6.5, 1.5 Hz, 3 H).
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

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F. Weber et al.
Paper
Synthesis
13C NMR (126 MHz, CDCl3): δ [(Z)-2a] = 200.9, 122.1, 104.9, 23.5, 10.9.
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in acetoni-
trile (0.3 mL) then Ph2PH solution (0.125 M in acetonitrile, 0.2 mL,
25.0 μmol, 5 mol%) was added. N-Allylcinnamamide (94 mg, 0.502
mmol, 1.0 equiv) was added at ambient temperature and the reaction
mixture was stirred for 6 d at 83 °C. Workup according to the general
procedure and purification by flash column chromatography (n-pen-
tane/diethyl ether, 4:1) afforded a Z/E-mixture of 2d.
The NMR spectra for both isomers are consistent with reported da-
ta.3a
(Z)-N-(Prop-1-en-1-yl)octanamide (2b)
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. N-Allyloctanamide
(92 mg, 0.502 mmol, 1.0 equiv) were added at ambient temperature
and the reaction mixture was stirred for 90 min. Workup according to
the general procedure and purification by flash column chromatogra-
phy (n-pentane/diethyl ether, 7:1) afforded a Z/E-mixture of 2b.
Yield: 51 mg (0.272 mmol, 54%); white solid; Z/E = 50:50.
1H NMR (300 MHz, CDCl3): δ [(Z)-2d] = 7.73 (d, J = 15.5 Hz, 1 H), 7.54–
7.48 (m, 2 H), 7.38–7.35 (m, 3 H), 7.15 (d, J = 13.1 Hz, 1 H), 6.96–6.86
(m, 1 H), 6.47 (d, J = 15.5 Hz, 1 H), 4.90 (dq, J = 15.8, 8.0 Hz, 1 H), 1.70
(dt, J = 7.5, 1.5 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2d] = 7.70 (d, J =
15.5 Hz, 1 H), 6.41 (d, J = 15.6 Hz, 1 H), 5.26 (dq, J = 14.1, 6.9 Hz, 1 H).
Yield: 39 mg (0.213 mmol, 42%); white solid; mp 32–35 °C; Z/E =
82:18.
13C NMR (76 MHz, CDCl3): δ [(Z)-2d] = 163.0, 142.2, 134.8, 130.0,
128.99, 128.1, 122.3, 120.0, 106.1, 11.2.
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-2d] = 162.8, 142.7,
IR (neat): 3190, 2957, 2944, 2917, 2854, 1678, 1650, 1513, 1465,
1456, 1410, 1383, 1324, 1274, 1260, 1232, 1213, 1195, 1149, 1028,
952, 925, 740, 708, 599, 577 cm–1
.
1H NMR (300 MHz, CDCl3): δ = [(Z)-2b] = 6.86 (br. s, 1 H), 6.74 (qq, J =
8.8, 1.6 Hz, 1 H), 4.78 (dq, J = 15.6, 7.7 Hz, 1 H), 2.26 (t, J = 7.8 Hz, 2 H),
1.69–1.59 (m, 5 H), 1.29 (dd, J = 7.1, 1.4 Hz, 8 H), 0.88 (t, J = 6.9 Hz,
3 H).
134.9, 130.1, 128.96, 128.0, 123.7, 120.2, 108.7, 15.1.
The NMR spectra for both isomers are consistent with reported da-
ta.6a
1H NMR (300 MHz, CDCl3): δ = [resolved signals (E)-2b] = 5.12 (dq, J =
14.0, 6.8 Hz, 1 H), 2.18 (t, J = 7.9 Hz, 2 H), 1.68–1.64 (m, 3 H).
13C NMR (76 MHz, CDCl3): δ = [(Z)-2b] = 170.3, 122.2, 104.7, 37.0,
31.8, 29.4, 29.1, 25.7, 22.7, 14.2, 10.9.
13C NMR (76 MHz, CDCl3): δ = [(E)-2b] = 123.5, 107.4, 36.8, 14.9.
(Z)-N-(Prop-1-en-1-yl)benzamide (2e)
[Z: CAS Reg. No. 5500-46-9; E: CAS Reg. No. 5202-76-6]
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–30 °C, N-allylbenzamide (83 mg, 0.514 mmol, 1.0 equiv) was added.
The reaction mixture was stirred for 64 h at –30 °C. Workup accord-
ing to the general procedure and purification by flash column chro-
matography (n-pentane/diethyl ether, 4:1) afforded a Z/E-mixture of
2e.
HRMS (ESI): m/z [M + H]+ calcd for C11H22NO: 183.1696; found:
183.1696.
(Z)-2-Phenyl-N-(prop-1-en-1-yl)acetamide (2c)
[Z: CAS Reg. No. 1450916-51-4; E: CAS Reg. No. 1450916-50-3]
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–30 °C, N-allyl-2-phenylacetamide (88 mg, 0.502 mmol, 1.0 equiv)
was added. The reaction mixture was stirred for 64 h at –30°C. Work-
up according to the general procedure and purification by flash col-
umn chromatography (n-pentane/diethyl ether, 2:1) afforded a Z/E-
mixture of 2c.
Yield: 61 mg (0.379 mmol, 74%); white solid; Z/E = 91:9.
1H NMR (300 MHz, CDCl3): δ [(Z)-2e] = 7.80 (dd, J = 7.0, 1.5 Hz, 2 H),
7.60 (s, 1 H), 7.56–7.43 (m, 3 H), 6.94 (ddq, J = 10.7, 7.2, 1.7 Hz, 1 H),
4.94 (dq, J = 14.4, 7.3 Hz, 1 H), 1.70 (dd, J = 7.1, 1.8 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2e] = 5.32 (dq, J =
13.6, 6.9 Hz, 1 H), 1.73 (dd, J = 6.7, 1.7 Hz, 3 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-2e] = 164.4, 134.2, 132.0, 128.9,
127.2, 122.4, 106.2, 11.1.
Yield: 53 mg (0.303 mmol, 60%); colourless oil; Z/E = 92:8.
The NMR spectra for both isomers are consistent with reported da-
ta.6a
1H NMR (300 MHz, CDCl3): δ [(Z)-2c] = 7.42–7.28 (m, 5 H), 6.86 (s,
1 H), 6.69 (tt, J = 9.7, 1.8 Hz, 1 H), 4.76 (dq, J = 15.6, 7.6 Hz, 1 H), 3.66
(s, 2 H), 1.36 (dd, J = 7.0, 1.6 Hz, 3 H).
(Z)-2,4,6-Trimethyl-N-(prop-1-en-1-yl)benzamide (2f)
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2c] = 5.01 (dq, J =
14.0, 6.8 Hz, 1 H), 3.60 (s, 2 H), 1.61 (dd, J = 6.8, 1.5 Hz, 3 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-2c] = 168.0, 134.5, 129.6, 129.4,
127.8, 121.9, 105.8, 43.9, 10.6.
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-2c] = 14.8.
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. N-Allyl-2,4,6-
trimethylbenzamide (102 mg, 0.502 mmol, 1.0 equiv) was added at
ambient temperature and the reaction mixture was stirred for 7 d at
ambient temperature. Additional Ni(dppp)Cl2 (14 mg, 25.0 μmol,
5 mol%), zinc powder (3.3 mg), zinc iodide (16 mg, 50 μmol, 10 mol%
each) and Ph2PH solution (0.125 M in dichloromethane, 0.1 mL,
12.5 μmol, 2.5 mol%) were added to the reaction mixture after 48 h,
The NMR spectra for both isomers are consistent with reported da-
ta.6a
(Z/E)-N-(Prop-1-en-1-yl)cinnamamide (2d)
[Z: CAS Reg. No. 1814908-99-0; E: CAS Reg. No. 1814908-98-9]
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

G
F. Weber et al.
Paper
Synthesis
and the mixture was stirred for 4 d at ambient temperature to com-
plete the conversion of the starting material. Workup according to the
general procedure and purification by flash column chromatography
(n-pentane/diethyl ether, 4:1) afforded a Z/E-mixture of 2f. The Z-iso-
mer appears as a rotameric mixture.
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–20 °C, N-allyl-4-chlorobenzamide (98 mg, 0.501 mmol, 1.0 equiv)
was added. The reaction mixture was stirred for 39 h at –20°C. Work-
up according to the general procedure and purification by flash col-
umn chromatography (n-pentane/diethyl ether, 4:1) afforded a Z/E-
mixture of 2h.
Yield: 48 mg (0.236 mmol, 47%); Z/E = 86:14; white solid; mp 123–
128 °C.
IR (neat): 3257, 3177, 2917, 2858, 1730, 1677, 1641, 1503, 1438,
1319, 1286, 1177, 1142, 1114, 1015, 965, 882, 749, 726, 622, 485, 449
cm–1
.
Yield: 65 mg (0.332 mmol, 66%); Z/E = 81:19; white solid; mp 87–
89 °C.
1H NMR (300 MHz, CDCl3): δ = [main rotamer of (Z)-2f] = 7.05 (d, J =
9.6 Hz, 1 H), 6.96–6.90 (m, 1 H), 6.88 (s, 2 H), 4.91 (dq, J = 15.0, 7.4 Hz,
1 H), 2.30 (s, 9 H), 1.59 (dd, J = 7.3, 1.0 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ = [resolved signals minor rotamer of (Z)-
2f] = 6.86 (s, 2 H), 5.77–5.72 (m, 1 H), 4.54 (dq, J = 14.8, 7.9 Hz, 1 H),
2.22 (s, 9 H), 1.63 (dd, J = 7.4, 1.7 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ = [resolved signals (E)-2f] = 6.84 (s, 2 H),
5.22–5.15 (m, 1 H), 2.27 (s, 9 H), 1.72 (d, J = 6.9 Hz, 3 H).
13C NMR (126 MHz, CDCl3): δ = [main rotamer of (Z)-2f] = 167.7,
139.1, 134.7, 128.5, 128.4, 121.9, 106.1, 21.2, 19.4, 11.1.
13C NMR (126 MHz, CDCl3): δ = [resolved signals minor rotamer of (Z)-
2f] = 167.6, 138.95, 128.40, 123.6, 104.8, 19.1, 10.6.
13C NMR (126 MHz, CDCl3): δ = [resolved signals (E)-2f] = 171.4,
138.92, 128.38, 123.4, 108.6, 21.3, 19.3, 15.0.
IR (neat): 3290, 1637, 1593, 1516, 1479, 1276, 1149, 1091, 1013, 953,
868, 843, 731, 666, 524, 489, 442 cm–1
.
1H NMR (300 MHz, CDCl3): δ [(Z)-2h] = 7.74 (d, J = 8.5 Hz, 2 H), 7.54 (s,
1 H), 7.44 (d, J = 8.7 Hz, 2 H), 6.95–6.88 (m, 1 H), 4.97 (dq, J = 14.4,
7.1 Hz, 1 H), 1.71 (dd, J = 7.1, 1.7 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2h] = 5.32 (dq, J =
14.1, 6.7 Hz, 1 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-2h] = 163.4, 138.4, 132.5, 129.2,
128.6, 122.3, 106.7, 11.1.
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-2h] = 129.1, 123.6,
109.4, 15.1.
HRMS (ESI): m/z [M + Na]+ calcd for C10H10ClNONa: 218.0343; found:
218.0344.
HRMS (ESI): m/z [M + Na]+ calcd for C13H17NONa: 226.1202; found:
226.1204.
(Z)-4-Bromo-N-(prop-1-en-1-yl)benzamide (2i)
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–25 °C, N-allyl-4-bromobenzamide (120 mg, 0.502 mmol, 1.0 equiv)
was added. The reaction mixture was stirred for 69 h at –25°C. Work-
up according to the general procedure and purification by flash col-
umn chromatography (n-pentane/diethyl ether, 4:1) afforded a Z/E-
mixture of 2i.
(Z)-4-Methoxy-N-(Prop-1-en-1-yl)benzamide (2g)
[Z: CAS Reg. No. 421556-62-9; E: CAS Reg. No. 1450916-45-6]
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. N-Allyl-4-methoxy-
benzamide (96 mg, 0.502 mmol, 1.0 equiv) was added at ambient
temperature and the reaction mixture was stirred for 8 d at ambient
temperature. Workup according to the general procedure and purifi-
cation by flash column chromatography (n-pentane/diethyl ether, 4:1
→ 2:1) afforded a Z/E-mixture of 2g.
Yield: 74 mg (0.310 mmol, 62%); white solid; mp 94–98 °C for (Z)-2i,
160 °C for (E)-2i; Z/E = 93:7.
IR (neat): 3295, 1636, 1589, 1509, 1477, 1366, 1273, 1178, 1147,
Yield: 67 mg (0.350 mmol, 70%); Z/E = 64:36; colourless oil, solidifies
upon storage.
1068, 1008, 866, 837, 728, 673, 611, 512, 446 cm–1
.
1H NMR (300 MHz, CDCl3): δ [(Z)-2i] = 7.67 (d, J = 8.6 Hz, 2 H), 7.58 (d,
J = 8.6 Hz, 2 H), 6.89 (dt, J = 9.8, 1.6 Hz, 1 H), 4.96 (dq, J = 15.9, 7.8 Hz,
1 H), 1.70 (dd, J = 7.1, 1.6 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2i] = 5.26 (dq, J =
14.0, 6.9 Hz, 1 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-2i] = 163.5, 133.0, 132.2, 129.0,
128.8, 126.8, 122.3, 106.8, 11.1.
HRMS (ESI): m/z [M + Na]+ calcd for C10H10BrNONa: 263.9818; found:
263.9821.
1H NMR (300 MHz, CDCl3): δ [(Z)-2g] = 7.77 (t, J = 7.4 Hz, 2 H), 7.52 (s,
1 H), 6.94 (t, J = 8.4 Hz, 3 H), 4.90 (dq, J = 14.2, 7.1 Hz, 1 H), 3.86 (s,
3 H), 1.72 (t, J = 7.1 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2g] = 5.27 (dq, J =
14.2, 6.8 Hz, 1 H), 3.85 (s, 3 H), 1.71 (t, J = 6.9 Hz, 3 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-2g] = 163.9, 162.7, 129.0, 126.4,
122.6, 114.1, 105.5, 55.59, 11.0.
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-2g] = 162.6, 128.9,
126.3, 124.0, 114.0, 108.2, 55.56, 15.1.
The NMR spectra for the Z-configured isomer are consistent with re-
(Z)-N-(Prop-1-en-1-yl)-4-(trifluoromethyl)benzamide (2j)
[Z: CAS Reg. No. 1450916-47-8; E: CAS Reg. No. 1450916-46-7]
ported data.11
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
(Z)-4-Chloro-N-(prop-1-en-1-yl)benzamide (2h)
[Z: CAS Reg. No. 1450916-49-0; E: CAS Reg. No. 1450916-48-9]
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

H
F. Weber et al.
Paper
Synthesis
18 °C, N-allyl-4-trifluoromethylbenzamide (113 mg, 0.493 mmol, 1.0
equiv) was added. The reaction mixture was stirred for 45 h at 18°C.
Workup according to the general procedure and purification by flash
column chromatography (n-pentane/diethyl ether, 4:1) afforded a
Z/E-mixture of 2j.
amide (33 mg, 0.215 mmol, 1.0 equiv) was added at ambient tem-
perature and the reaction mixture was stirred for 2 d. Additional
Ni(dppp)Cl2 (7 mg, 12.5 μmol, 5 mol%), zinc powder (1.7 mg), zinc io-
dide (8 mg, 25 μmol, 10 mol% each), and Ph2PH solution (0.125 M in
dichloromethane, 0.05 mL, 6.0 μmol, 2.5 mol%) were added to the re-
action mixture which was stirred for 48 h at ambient temperature to
complete the conversion of the starting material. Workup according
to the general procedure and purification by flash column chromatog-
raphy (n-pentane/diethyl ether, 2:1) afforded a Z/E-mixture of 2m.
Yield: 71 mg (0.310 mmol, 63%); white solid; mp 172 °C; Z/E = 78:22.
IR (neat): 3294, 1678, 1635, 1580, 1529, 1505, 1438, 1409, 1320,
1258, 1162, 1119, 1076, 1062, 1016, 954, 859, 847, 795, 726, 693,
680, 600, 469 cm–1
.
Yield: 21 mg (0.137 mmol, 64%); colourless oil; Z/E = 15:85.
1H NMR (300 MHz, CDCl3): δ [(Z)-2j] = 7.92 (d, J = 8.0 Hz, 2 H), 7.73 (d,
J = 8.4 Hz, 2 H), 7.59 (br. s, 1 H), 6.99–6.89 (m, 1 H), 5.00 (dq, J = 14.5,
7.1 Hz, 1 H), 1.72 (dd, J = 7.0, 1.8 Hz, 1 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2j] = 5.36 (dq, J =
14.8, 7.3 Hz, 1 H), 1.75 (dd, J = 7.0, 1.6 Hz, 3 H).
13C NMR (126 MHz, CDCl3): δ [(Z)-2j] = 163.3, 137.4, 133.7 (q, J =
32.9 Hz), 127.7, 125.9 (q, J = 3.7 Hz), 123.7 (q, J = 272.6 Hz), 122.1,
107.4, 11.2.
IR (neat): 3289, 3214, 3078, 1698, 1542, 1439, 1300, 1273, 1215,
1157, 947, 871, 774, 520 cm–1
.
1H NMR (300 MHz, CDCl3): δ [(E)-2m] = 7.77 (s, 1 H), 6.65 (t, J =
11.6 Hz, 1 H), 5.50 (qd, J = 14.1, 7.1 Hz, 1 H), 1.73 (dd, J = 6.9, 1.4 Hz,
3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (Z)-2m] = 5.16 (dq, J =
8.2, 5.7 Hz, 1 H), 1.69 (dd, J = 7.1, 1.5 Hz, 3 H).
13C NMR (76 MHz, CDCl3): δ [(E)-2m] = 121.0, 114.2, 111.5, 15.0.
13C NMR (76 MHz, CDCl3): δ [resolved signals (Z)-2m] = 11.1.
19F NMR (283 MHz, CDCl3): δ [(E)-2m] = –75.77 (s, 3F).
19F NMR (283 MHz, CDCl3): δ [(Z)-2m] = –75.70 (s, 3F).
13C NMR (126 MHz, CDCl3): δ [resolved signals (E)-2j] = 163.0, 137.3,
125.8 (q, J = 3.9 Hz), 123.4, 110.1, 15.1.
19F NMR (283 MHz, CDCl3): δ [(Z)-2j] = –63.13 (s, 3 F).
19F NMR (283 MHz, CDCl3): δ [(E)-2j] = –63.12 (s, 3 F).
HRMS (ESI): m/z [M + H]+ calcd for C11H11F3NO: 230.0787; found:
HRMS (ESI): m/z [M + Na]+ calcd for C5H6F3NONa: 176.0299; found:
230.0789.
176.0299.
(Z)-N-(Prop-1-en-1-yl)thiophene-2-carboxamide (2k)
[E: CAS Reg. No. 731852-78-1]
tert-Butyl (Z)-Prop-1-en-1-ylcarbamate (4a)
[Z: CAS Reg. No. 119973-55-6; E: CAS Reg. No. 119973-54-5]
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to 5 °C,
N-allylthiophene-2-carboxamide (84 mg, 0.502 mmol, 1.0 equiv) was
added. The reaction mixture was stirred for 3 d at 5°C. Workup ac-
cording to the general procedure and purification by flash column
chromatography (n-pentane/diethyl ether, 4:1) afforded a Z/E-mix-
ture of 2k.
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–30 °C, tert-butyl allylcarbamate (79 mg, 0.503 mmol, 1.0 equiv) was
added and the reaction mixture was stirred for 19 h at –30 °C. Work-
up according to the general procedure and purification by flash col-
umn chromatography (n-pentane/diethyl ether, 3:1) afforded a Z/E-
mixture of 4a.
Yield: 28 mg (0.167 mmol, 33%); Z/E = 84:16; colourless oil.
Yield: 62 mg (0.395 mmol, 79%); colourless oil; Z/E = 81:19.
1H NMR (300 MHz, CDCl3): δ [(Z)-2k] = 7.57 (dd, J = 3.6, 0.9 Hz, 1 H),
7.52 (dd, J = 5.1, 0.9 Hz, 1 H), 7.43 (s, 1 H), 7.11 (dd, J = 4.9, 1.1 Hz,
1 H), 6.91–6.84 (m, 1 H), 4.92 (dq, J = 8.5, 7.3 Hz, 1 H), 1.70 (dd, J = 7.1,
1.7 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-2k] = 7.08 (dd, J =
5.0, 1.0 Hz, 1 H), 5.29 (m, 1 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-2k] = 158.9, 138.4, 130.8, 128.7,
127.9, 122.0, 106.1, 11.1.
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-2k] = 130.6, 128.5,
127.9, 123.3, 108.9, 15.0.
1H NMR (300 MHz, CDCl3): δ [(Z)-4a] = 6.42 (t, J = 10.4 Hz, 1 H), 6.09
(s, 1 H), 4.67–4.59 (m, 1 H), 1.55 (dd, J = 6.9, 1.6 Hz, 3 H), 1.48 (s, 9 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-4a] = 4.96–4.87 (m,
1 H), 1.63 (dd, J = 6.6, 1.5 Hz, 3 H), 1.46 (s, 9 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-4a] = 153.0, 123.3, 102.0, 80.5, 28.4,
10.6.
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-4a] = 124.5, 104.5,
15.4.
The NMR spectra for both isomers are consistent with reported da-
ta.6a
The NMR spectra for both isomers are consistent with reported da-
ta.3a
Benzyl (Z)-prop-1-en-1-ylcarbamate (4b)
[Z: CAS Reg. No. 260967-06-4; E: CAS Reg. No. 260967-14-4]
(E)-2,2,2-Trifluoro-N-(prop-1-en-1-yl)acetamide (2m)
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–30 °C, benzyl allylcarbamate (96 mg, 0.502 mmol, 1.0 equiv) was
added and the reaction mixture was stirred for 17 h at –30 °C. Work-
[CAS Reg. No. 201792-59-8]
The title compound was prepared by utilising Ni(dppp)Cl2 (14 mg,
25.0 μmol, 10 mol%), zinc powder (3.3 mg) and zinc iodide (16 mg,
50 μmol, 20 mol% each). These materials were suspended in dichloro-
methane (0.15 mL) then Ph2PH solution (0.125 M in dichloromethane,
0.1 mL, 12.5 μmol, 5 mol%) was added. N-Allyl-2,2,2-trifluoroacet-
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

I
F. Weber et al.
Paper
Synthesis
up according to the general procedure and purification by flash col-
umn chromatography (n-pentane/diethyl ether, 4:1) afforded a Z/E-
mixture of 4b.
13C NMR (76 MHz, CDCl3): δ = 172.7, 124.6, 106.9, 45.4, 31.4, 17.6,
15.3.
The NMR spectra are consistent with reported data.6a
Yield: 66 mg (0.345 mmol, 69%); colourless oil; Z/E = 81:19.
1H NMR (500 MHz, CDCl3): δ [(Z)-4b] = 7.38–7.32 (m, 5 H), 6.50–6.45
(m, 1 H), 6.37 (br. s, 1 H), 5.16 (s, 2 H), 4.70 (dq, J = 14.3, 7.2 Hz, 1 H),
1.55 (dd, J = 7.0, 1.6 Hz, 3 H).
(E)-3-(Prop-1-en-1-yl)oxazolidin-2-one (6b)
[Z: CAS Reg. No. 1018683-47-0; E: CAS Reg. No. 201792-65-6]
The title compound was prepared by utilising Ni(dppp)Cl2 (14 mg,
25.0 μmol, 10 mol%), zinc powder (3.3 mg) and zinc iodide (16 mg,
50 μmol, 20 mol% each). These materials were suspended in dichloro-
methane (0.15 mL) then Ph2PH solution (0.125 M in dichloromethane,
0.1 mL, 12.5 μmol, 5 mol%) was added. 3-Allyloxazolidin-2-one
(32 mg, 0.250 mmol, 1.0 equiv) was added at ambient temperature
and the reaction mixture was stirred for 16 h at ambient temperature.
Workup according to the general procedure and purification by flash
column chromatography (n-pentane/EtOAc, 2:1) afforded a Z/E-mix-
ture of 6b.
1H NMR (500 MHz, CDCl3): δ [resolved signals (E)-4b] = 5.03–4.97 (m,
1 H), 1.65 (d, J = 6.4 Hz, 3 H).
13C NMR (126 MHz, CDCl3): δ [(Z)-4b] = 153.7, 136.1, 128.72, 128.48,
128.4, 123.1, 103.3, 67.3, 10.6.
13C NMR (126 MHz, CDCl3): δ [resolved signals (E)-4b] = 153.6,
128.66, 128.51, 128.3, 124.1, 105.9, 67.1, 14.8.
The NMR spectra for both isomers are consistent with reported da-
ta.6a
Yield: 30 mg (0.236 mmol, 94%); colourless oil; Z/E = 6:94.
(Z)-Prop-1-en-1-yl Phenylcarbamate (4c)
1H NMR (300 MHz, CDCl3): δ [(E)-6b] = 6.65 (d, J = 14.5 Hz, 1 H), 4.81
(dt, J = 14.1, 7.2 Hz, 1 H), 4.42 (t, J = 8.0 Hz, 2 H), 3.67 (t, J = 8.1 Hz,
2 H), 1.72 (dd, J = 7.0, 1.0 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (Z)-6b] = 6.23 (d, J =
7.6 Hz, 1 H), 5.02–4.91 (m, 1 H), 3.98 (t, J = 7.9 Hz, 2 H).
13C NMR (76 MHz, CDCl3): δ [(E)-6b] = 155.5, 124.8, 105.8, 62.2, 42.8,
15.0.
The NMR spectra are consistent with reported data.5
[Z: CAS Reg. No. 345622-30-2; E: CAS Reg. No. 868388-40-3]
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. After cooling to
–20 °C, allyl phenylcarbamate (89 mg, 0.502 mmol, 1.0 equiv) was
added and the reaction mixture was stirred for 48 h at –20 °C. Work-
up according to the general procedure and purification by flash col-
umn chromatography (n-pentane/diethyl ether, 8:1) afforded a Z/E-
mixture of 4c.
(E)-1-(Prop-1-en-1-yl)azepan-2-one (6c)
[CAS Reg. No. 140165-85-1]
Yield: 32 mg (0.181 mmol, 36%); white solid; Z/E = 87:13.
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. 1-Allylazepan-2-one
(77 mg, 0.502 mmol, 1.0 equiv) was added at ambient temperature
and the reaction mixture was stirred for 16 h. Workup according to
the general procedure and purification by flash column chromatogra-
phy (n-pentane/EtOAc 2:1) gave 6c as a single E-isomer.
1H NMR (300 MHz, CDCl3): δ [(Z)-4c] = 7.41 (t, J = 7.8 Hz, 2 H), 7.33 (t,
J = 7.7 Hz, 2 H), 7.10 (t, J = 7.3 Hz, 1 H), 7.03–7.00 (m, 1 H), 6.79 (s,
1 H), 4.90 (dq, J = 13.6, 6.7 Hz, 1 H), 1.69 (dd, J = 6.9, 1.7 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (E)-4c] = 5.38 (dq, J =
12.4, 6.9 Hz, 1 H).
13C NMR (76 MHz, CDCl3): δ [(Z)-4c] = 151.0, 137.4, 135.4, 129.3,
124.1, 119.1, 107.3, 9.8.
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-4c] = 136.4, 12.4.
Yield: 59 mg (0.385 mmol, 77%); white solid.
The NMR spectra for both isomers are consistent with reported da-
ta.12
1H NMR (300 MHz, CDCl3): δ = 7.11 (dd, J = 14.6, 1.3 Hz, 1 H), 5.10–
4.98 (m, 1 H), 3.55 (t, J = 4.7 Hz, 2 H), 2.59 (t, J = 5.4 Hz, 2 H), 1.73–
1.70 (m, 6 H), 1.68–1.63 (m, 3 H).
13C NMR (76 MHz, CDCl3): δ = 174.0, 127.8, 106.0, 45.8, 37.4, 29.7,
27.6, 23.6, 15.4.
(E)-1-(Prop-1-en-1-yl)pyrrolidin-2-one (6a)
[CAS Reg. No. 140165-83-9]
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. 1-Allylpyrrolidin-2-
one (62 mg, 0.495 mmol, 1.0 equiv) was added at ambient tempera-
ture and the reaction mixture was stirred for 24 h. Workup according
to the general procedure and purification by flash column chroma-
tography (n-pentane/diethyl ether, 2:1), 6a was obtained as a single
E-isomer.
The NMR spectra are consistent with reported data.3c
(E)-2-(Prop-1-en-1-yl)isoindoline-1,3-dione (6d)
[CAS Reg. No. 93250-83-0]
The title compound was prepared by utilising Ni(dppp)Br2 (32 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. 2-Allylisoindoline-
1,3-dione (94 mg, 0.502 mmol, 1.0 equiv) was added at ambient tem-
perature and the reaction mixture was stirred for 18 h. Workup ac-
cording to the general procedure and purification by flash column
chromatography (n-pentane/tert-butyl methyl ether, 20:1) gave 6d as
a single E-isomer.
Yield: 61 mg (0.487 mmol, 98%); colourless liquid.
1H NMR (300 MHz, CDCl3): δ = 6.88 (d, J = 14.1 Hz, 1 H), 4.94 (qd, J =
14.1, 7.4 Hz, 1 H), 3.48 (t, J = 7.2 Hz, 2 H), 2.46 (t, J = 8.1 Hz, 2 H), 2.12–
2.02 (m, 2 H), 1.72 (dd, J = 6.7 1.3 Hz, 3 H).
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

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F. Weber et al.
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Synthesis
Yield: 80 mg (0.426 mmol, 85%); yellow solid.
13C NMR (76 MHz, CDCl3): δ [(Z)-8] = 158.5, 129.6, 123.9, 61.8, 44.2,
40.7, 13.0.
1H NMR (300 MHz, CDCl3): δ = 7.87–7.83 (m, 2 H), 7.75–7.70 (m, 2 H),
6.64–6.53 (m, 2 H), 1.84 (d, J = 5.0 Hz, 3 H).
13C NMR (76 MHz, CDCl3): δ = 168.8, 134.4, 131.9, 123.6, 118.5, 118.3,
13C NMR (76 MHz, CDCl3): δ [resolved signals (E)-8] = 44.6, 17.9.
13C NMR (76 MHz, CDCl3): δ [resolved signals SM] = 43.6, 32.1.
16.4.
HRMS (ESI): m/z [M + Na]+ calcd for C7H11NO2Na: 164.0682; found:
164.0682.
The NMR spectra are consistent with reported data.5
(E)-2-(But-2-en-2-yl)isoindoline-1,3-dione (6e)
(E)-3-(But-1-en-1-yl)oxazolidin-2-one (9)
[CAS Reg. No. 860765-74-8]
[CAS Reg. No. 1262432-02-9]
The title compound was prepared by utilising Ni(dppp)Cl2 (14 mg,
25.0 μmol, 10 mol%), zinc powder (3.3 mg) and zinc iodide (16 mg,
50 μmol, 20 mol% each). These materials were suspended in dichloro-
methane (0.15 mL) then Ph2PH solution (0.125 M in dichloromethane,
0.1 mL, 12.5 μmol, 5 mol%) was added. After cooling to 0 °C, 2-(but-3-
en-2-yl)isoindoline-1,3-dione (50 mg, 0.250 mmol, 1.0 equiv) was
added and the reaction mixture was stirred for 3 d at 0 °C. Workup
according to the general procedure and purification by flash column
chromatography (n-pentane/EtOAc, 9:1) gave 6e.
The title compound was prepared by utilising Ni(dppp)Cl2 (28 mg,
50.0 μmol, 10 mol%), zinc powder (6.6 mg) and zinc iodide (32 mg,
100 μmol, 20 mol% each). These materials were suspended in di-
chloromethane (0.3 mL) then Ph2PH solution (0.125 M in dichloro-
methane, 0.2 mL, 25.0 μmol, 5 mol%) was added. 3-(But-3-en-1-
yl)oxazolidin-2-one (71 mg, 0.503 mmol, 1.0 equiv) was added at am-
bient temperature and the reaction mixture was stirred for 16 h.
Workup according to the general procedure and purification by flash
column chromatography (n-pentane/EtOAc, 1:1) gave 9 as a single E-
isomer.
Yield: 35 mg (0.170 mmol, 70%); colourless oily solid; Z/E = 33:67.
Yield: 58 mg (0.411 mmol, 82%); colourless oil.
IR (neat): 3464, 2977, 2924, 2861, 1715, 1699, 1308, 1286, 1121,
1078, 885, 713, 530 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 6.65 (d, J = 14.2 Hz, 1 H), 4.86 (dt, J =
14.4, 7.2 Hz, 1 H), 4.42 (t, J = 8.1 Hz, 2 H), 3.68 (t, J = 8.0 Hz, 2 H), 2.09
(dq, J = 7.1, 1.2 Hz, 2 H), 1.02 (t, J = 7.4 Hz, 3 H).
13C NMR (76 MHz, CDCl3): δ = 155.6, 123.5, 113.5, 62.2, 42.8, 23.1,
14.6.
1H NMR (300 MHz, CDCl3): δ [(E)-6e] = 7.90–7.83 (m, 2 H), 7.77–7.71
(m, 2 H), 5.58 (q, J = 7.0 Hz, 1 H), 1.97 (s, 3 H), 1.83 (d, J = 7.0 Hz, 3 H).
1H NMR (300 MHz, CDCl3): δ [resolved signals (Z)-6e] = 5.81 (q, J =
6.9 Hz, 1 H), 2.00 (s, 3 H), 1.53 (d, J = 6.8 Hz, 3 H).
The NMR spectra are consistent with reported data.13
13C NMR (76 MHz, CDCl3): δ [(E)-6e] = 167.7, 134.2, 132.2, 127.2,
127.0, 123.6, 15.7, 13.4.
13C NMR (76 MHz, CDCl3): δ [resolved signals (Z)-6e] = 167.1, 134.1,
132.4, 127.2, 126.0, 123.5, 21.1, 13.5.
Acknowledgment
HRMS (ESI): m/z [M + Na]+ calcd for C12H11NO2Na: 224.0682; found:
224.0682.
This work was supported by the Deutsche Forschungsgemeinschaft
(Hi 655 17-1). We are particularly grateful to Dr. Georg Manolikakes
and Philipp Kramer for drawing our attention to the translocation of
double bonds in N-allyl amides.
(Z)-3-(But-2-en-1-yl)oxazolidin-2-one (8)
[E: CAS Reg. No. 167483-80-9]
The title compound was prepared by utilising Ni(dppp)Cl2 (14 mg,
25.0 μmol, 10 mol%), zinc powder (3.3 mg) and zinc iodide (16 mg,
50 μmol, 20 mol% each). These materials were suspended in dichloro-
methane (0.15 mL) then Ph2PH solution (0.125 M in dichloromethane,
0.1 mL, 12.5 μmol, 5 mol%) was added. After cooling to –10 °C, 3-(but-
3-en-1-yl)oxazolidin-2-one (36 mg, 0.251 mmol, 1.0 equiv) was add-
ed at ambient temperature and the reaction mixture was stirred for
16 h at –10 °C. Workup according to the general procedure and purifi-
cation by flash column chromatography (n-pentane/EtOAc 1:1) gave 8
as an Z/E-mixture (84:16) that contained some remaining starting
material (SM; 11%).
Supporting Information
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0036-1588340.
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References
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.
1H NMR (300 MHz, CDCl3): δ [(Z)-8] = 5.79–5.64 (m, 1 H), 5.45–5.34
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© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K

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Paper
Synthesis
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© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–K