G. Kiefer, J. Ruiz, E. Solari, G. Hilt, K. Severin
FULL PAPER
spectrometer with the residual solvents as internal standards. All
spectra were recorded at room temperature. The isolated yields re-
fer to isomer A plus isomer B (see Table 2), whereas the NMR data
are given for the main isomer A. Unless otherwise stated, all reac-
tions were performed under dry nitrogen. The solvents were ob-
tained from a solvent purification system from innovative technol-
ogies (IT).
7.2 Hz, 3 H) ppm. 13C NMR (100 MHz, CDCl3): (E) and (Z) ole-
fin: δ = 169.1, 140.5, 139.3, 138.2, 138.0, 133.8, 129.4, 128.1, 127.2,
126.8, 126.6, 62.2, 62.1, 54.9, 54.7, 44.2, 41.4, 40.5, 35.2, 21.2, 21.1,
14.0 ppm. HRMS (EI): calcd. for C15H18Cl2O2 [M]+ 300.0684;
found 300.0672.
2,6-Dichloro-4-(p-tolyl)hex-4-enenitrile: Table 2, Entry 4. Isolated
1
yield: 102 mg, 40%. H NMR (400 MHz, CDCl3): (E) olefin: δ =
General Procedure for the Sequential Enyne Cross-Metathesis/
7.24–7.19 (m, 4 H), 6.11 (t, J = 8.0 Hz, 1 H), 4.33–4.25 (m, 3 H),
3.37 (dd, J = 14.4, 7.2 Hz, 1 H), 3.28 (dd, J = 14.4, 8.0 Hz, 1 H),
2.37 (s, 3 H) ppm; (Z) olefin: δ = 7.22–7.20 (m, 2 H), 7.11–7.09 (m,
2 H), 5.93 (t, J = 7.8 Hz, 1 H), 4.18 (dd, J = 8.2, 7.4 Hz, 1 H), 3.99
(d, J = 7.8 Hz, 2 H), 3.28 (dd, J = 14.4, 6.9 Hz, 1 H), 3.05 (dd, J
= 14.4, 8.2 Hz, 1 H), 2.39 (s, 3 H) ppm. 13C NMR (100 MHz,
CDCl3): (E) and (Z) olefin: δ = 138.9, 138.7, 138.3, 137.6, 135.6,
132.5, 129.7, 129.4, 128.6, 128.0, 126.5, 116.47, 116.46, 45.6, 40.9,
40.44, 40.40, 29.9, 36.8, 21.2, 21.1 ppm. HRMS (EI): calcd. for
C13H13Cl2N [M]+ 253.0425; found 253.0435.
ATRA Reactions: The arylacetylene (1.0 mmol),
2 (42 mg,
50 μmol), and mesitylene (internal standard, 42 μL, 0.30 mmol)
were dissolved in toluene (10 mL). The solution was degassed un-
der vacuum, purged with ethylene gas (1 atm), and stirred at 30 °C.
After 90 min, ethylene was removed by cycling with vacuum/N2.
Ethyl dichloroacetate (160 μL, 1.3 mmol) and activated Mg
(486 mg, 20 mmol) were added, and the reaction mixture was
stirred vigorously at 80 °C for 16 h. The mixture was cooled to
room temperature, Mg was removed by filtration, and the solution
was concentrated under vacuum. The residue was purified by flash
chromatography on silica gel (cyclohexane/dichloromethane, 7:3 or
8:2; Table 2, Entry 10). The products were obtained as colorless or
pale yellow oils. The (E)/(Z) configuration was assigned by a
ROESY experiment. For ethyl 2,6-dichloro-4-phenylhex-4-enoate
(Table 2, Entry 1), the isomer for which NOE coupling of the ole-
finic proton with the phenyl protons was observed was assigned as
the (E) isomer. The stereochemistry of the other products was as-
signed by comparison of the GC and NMR spectroscopic data with
those of ethyl 2,6-dichloro-4-phenylhex-4-enoate.
Ethyl 2,6-Dichloro-4-(4-fluorophenyl)hex-4-enoate: Table 2, Entry 5.
Isolated yield: 174 mg, 57%. 1H NMR (400 MHz, CDCl3): (E) ole-
fin: δ = 7.32–7.27 (m, 2 H), 7.05–7.02 (m, 2 H), 5.96 (t, J = 8.0 Hz,
1 H), 4.28 (d, J = 8.0 Hz, 2 H), 4.22–4.10 (m, 3 H), 3.28 (dd, J =
14.8, 6.4 Hz, 1 H), 3.30 (dd, J = 14.8, 8.4 Hz, 1 H), 1.25 (t, J =
7.2 Hz, 3 H) ppm; (Z) olefin: δ = 7.12–7.06 (m, 2 H), 7.22–7.17 (m,
2 H), 5.85 (t, J = 8.0 Hz, 1 H), 4.22–4.10 (m, 2 H), 4.07 (dd, J =
8.4, 6.8 Hz, 1 H), 3.90 (m, 2 H), 3.13 (dd, J = 14.0, 6.8 Hz, 1 H),
2.94 (dd, J = 14.0, 8.4 Hz, 1 H), 1.25 (t, J = 7.2 Hz, 3 H) ppm. 13
C
NMR (100 MHz, CDCl3): (E) and (Z) olefin: δ = 168.96, 168.93,
162.7 (d, J = 246 Hz), 162.5 (d, J = 246 Hz), 139.5, 138.4, 135.8
(d, J = 3 Hz), 132.7 (d, J = 4 Hz), 130.0 (d, J = 8 Hz), 128.5 (d, J
= 8 Hz), 128.1, 127.5, 115.8 (d, J = 21 Hz), 115.6 (d, J = 22 Hz),
62.3, 62.2, 54.7, 54.5, 44.1, 41.0, 40.2, 35.3, 14.0, 13.9 ppm. HRMS
(EI): calcd. for C14H15Cl2FO2 [M]+ 304.0433; found 304.0449.
Ethyl 2,6-Dichloro-4-phenylhex-4-enoate: Table 2, Entry 1. Isolated
yield: 161 mg, 56%. H NMR (400 MHz, CDCl3): (E) olefin: δ =
1
7.42–7.30 (m, 4 H), 7.21–7.19 (m, 1 H), 6.00 (t, J = 8.0 Hz, 1 H),
4.30 (d, J = 8.0 Hz, 2 H), 4.22–4.11 (m, 3 H), 3.32 (dd, J = 14.4,
6.8 Hz, 1 H), 3.19 (dd, J = 14.8, 8.4 Hz, 1 H), 1.28 (t, J = 7.2 Hz,
3 H) ppm; (Z) olefin: δ = 7.42–7.30 (m, 4 H), 7.21–7.19 (m, 1 H),
5.84 (t, J = 8.0 Hz, 1 H), 4.22–4.11 (m, 2 H), 4.09 (dd, J = 8.4,
6.8 Hz, 1 H), 3.94 (d, J = 8.0 Hz, 2 H), 3.16 (dd, J = 14.4, 6.9 Hz,
1 H), 2.94 (dd, J = 14.4, 8.0 Hz, 1 H), 1.25 (t, J = 7.2 Hz, 3 H)
ppm. 13C NMR (100 MHz, CDCl3): (E) and (Z) olefins (CAr): δ =
128.7. 128.3, 128.20, 128.17, 128.0 ppm; (E) olefin: δ = 160.1, 139.7,
139.3, 126.8, 62.2, 54.8, 40.4, 35.2, 14.0 ppm; (Z) olefin: δ = 169.0,
140.4, 136.8, 127.1, 62.1, 54.6, 44.1, 41.3, 13.9 ppm. HRMS (EI):
calcd. for C14H16Cl2O2 [M]+ 286.0527; found 286.0534.
2,6-Dichloro-4-(4-fluorophenyl)hex-4-enenitrile: Table 2, Entry 6.
Isolated yield: 116 mg, 45%. 1H NMR (400 MHz, CDCl3): (E) ole-
fin: δ = 7.36–7.31 (m, 2 H), 7.14–7.08 (m, 2 H), 6.11 (t, J = 8.0 Hz,
1 H), 4.30 (d, J = 8.0 Hz, 2 H), 4.30 (dd, J = 8.0, 7.4 Hz, 1 H),
3.37 (dd, J = 14.8, 7.6 Hz, 1 H), 3.30 (dd, J = 14.8, 8.0 Hz, 1 H)
ppm; (Z) olefin: δ = 7.25–7.18 (m, 2 H), 7.17–7.08 (m, 2 H), 6.00
(t, J = 8.0 Hz, 1 H), 4.21 (dd, J = 8.0, 7.2 Hz, 1 H), 3.97 (d, J =
8.0 Hz, 2 H), 3.18 (dd, J = 14.0, 7.2 Hz, 1 H), 3.08 (dd, J = 14.4,
8.0 Hz, 1 H) ppm. 13C NMR (100 MHz, CDCl3): (E) and (Z) ole-
fin: δ = 163.0 (d, J = 249 Hz), 137.4, 136.8, 134.7 (d, J = 8 Hz),
130.0 (d, J = 8 Hz), 129.6, 129.0, 128.5 (d, J = 8 Hz), 125.3, 116.1
(d, J = 21 Hz), 45.5, 40.5, 40.3, 39.6, 37.0 ppm. HRMS (EI): calcd.
for C12H10Cl2FN [M]+ 257.0174; found 257.0175.
2,6-Dichloro-4-phenylhex-4-enenitrile: Table 2, Entry 2. Isolated
yield: 91 mg, 38%. 1H NMR (400 MHz, CDCl3): (E) olefin: δ =
7.45–7.31 (m, 4 H), 7.22–7.20 (m, 1 H), 6.13 (t, J = 8.0 Hz, 1 H),
4.30 (d, J = 8.0 Hz, 2 H), 4.29 (dd, J = 8.0, 7.4 Hz, 1 H), 3.32 (dd,
J = 14.4, 7.4 Hz, 1 H), 3.19 (dd, J = 14.4, 8.0 Hz, 1 H) ppm; (Z)
olefin: δ = 7.45–7.31 (m, 4 H), 7.22–7.20 (m, 1 H), 5.96 (t, J =
8.0 Hz, 1 H), 4.18 (dd, J = 8.4, 7.2 Hz, 1 H), 3.98 (d, J = 8.0 Hz,
2 H), 3.17 (dd, J = 14.0, 7.2 Hz, 1 H), 3.08 (dd, J = 14.0, 8.4 Hz,
1 H) ppm. 13C NMR (100 MHz, CDCl3): (E) and (Z) olefin: δ =
138.6, 137.7, 129.4, 129.0, 128.9, 128.1, 126.7, 116.4, 45.6, 40.4,
39.8, 36.9 ppm. HRMS (EI): calcd. for C12H11Cl2N [M]+ 239.0281;
found 239.0281.
Ethyl
2,6-Dichloro-4-[4-(trifluoromethyl)phenyl]hex-4-enoate:
Table 2, Entry 7. Isolated yield: 167 mg, 47%. 1H NMR (400 MHz,
CDCl3): (E) olefin: δ = 7.63 (dd, J = 8.8, 0.8 Hz, 2 H), 7.44 (dd, J
= 8.8, 0.8 Hz, 2 H), 6.05 (t, J = 8.0 Hz, 1 H), 4.29 (d, J = 8.0 Hz,
2 H), 4.20–4.04 (m, 3 H), 3.32 (dd, J = 14.8, 6.8 Hz, 1 H), 3.20
(dd, J = 14.8, 8.0 Hz, 1 H), 1.25 (t, J = 7.2 Hz, 3 H) ppm; (Z)
olefin: δ = 7.67 (dd, J = 8.4, 0.8 Hz, 2 H), 7.36 (dd, J = 8.4, 0.8 Hz,
2 H), 5.91 (t, J = 8.0 Hz, 1 H), 4.20–4.04 (m, 2 H), 4.09 (dd, J =
Ethyl 2,6-Dichloro-4-(p-tolyl)hex-4-enoate: Table 2, Entry 3. Iso-
lated yield: 157 mg, 52%. 1H NMR (400 MHz, CDCl3): (E) olefin: 8.4, 6.8 Hz, 1 H), 3.89–3.86 (m, 2 H), 3.17 (dd, J = 14.4, 6.4 Hz, 1
δ = 7.23–7.16 (m, 2 H), 7.11–7.08 (m, 2 H), 5.98 (t, J = 8.0 Hz, 1
H), 3.08 (dd, J = 14.4, 8.0 Hz, 1 H), 1.27 (t, J = 7.2 Hz, 3 H)
H), 4.29 (d, J = 8.0 Hz, 2 H), 4.21–4.12 (m, 3 H), 3.30 (dd, J = ppm. 13C NMR (100 MHz, CDCl3): (E) and (Z) olefin: δ = 168.77,
14.8, 6.8 Hz, 1 H), 3.19 (dd, J = 14.8, 8.0 Hz, 1 H), 2.36 (s, 1 H) 168.75, 143.4, 140.7, 139.2, 138.2, 130.4 (q, J = 32 Hz), 130.3 (q, J
1.26 (t, J = 7.2 Hz, 3 H) ppm; (Z) olefin: δ = 7.23–7.16 (m, 4 H), = 32 Hz), 129.8, 128.7, 128.2, 127.2, 125.71 (q, J = 4 Hz), 125.67
5.84 (t, J = 8.0 Hz, 1 H), 4.20–4.12 (m, 2 H), 4.08 (dd, J = 8.0,
6.8 Hz, 1 H), 3.95 (d, J = 8.0 Hz, 2 H), 3.16 (dd, J = 14.4, 6.8 Hz,
1 H), 2.91 (dd, J = 14.4, 8.0 Hz, 1 H), 2.37 (s, 3 H), 1.28 (t, J =
(q, J = 4 Hz), 123.93 (q, J = 270 Hz), 123.87 (q, J = 270 Hz), 62.4,
62.3, 54.6, 54.4, 43.8, 40.7, 39.9, 35.1, 14.0, 13.9 ppm. HRMS (EI):
calcd. for C15H15Cl2F3O2 [M]+ 354.0401; found 354.0388.
96
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Eur. J. Org. Chem. 2012, 93–98