Organometallics
Article
3.19 (s, 3H, OMe), 3.46 (s, 3H, OMe), 4.92 (dd, JHH = 10.6 Hz,
JPH = 7.4 Hz, 2H, CH), 5.15 (dd, JHH = 10.6 Hz, JPH = 5.7 Hz,
2H, CH); 31P{1H} NMR (162 MHz, toluene-d8, −40 °C) δ −22.2.
Synthesis of Pd(dimethyl fumarate)2(PCy3) (4-Cy). The
mono(tricyclohexylphosphine)(diallyl ether) palladium(0) complex
(78.2 mg, 0.161 mmol) was placed in a Schlenk tube under nitrogen,
and hexane was added. Then dimethyl fumarate (117.1 mg,
0.8125 mmol) in CH2Cl2/hexane was added to the solution, giving
a white participate immediately. After recrystallization from CH2Cl2
with hexane, Pd(dimethyl fumarate)2(PCy3) (4-Cy) was obtained as
yellow-brown crystals (35.4 mg, 0.0524 mmol, 33% yield). Anal. Calcd
for C30H49O8PPd: C, 53.37; H, 7.32. Found: C, 53.70; H, 7.54.
1H NMR (400 MHz, C6D6, 19 °C): δ 1.1−2.4 (m, 33H, PCy), 3.23
(s, 3H, OMe), 3.46 (s, 3H, OMe), 5.07 (dd, JHH = 11 Hz, JPH = 6.3 Hz,
2H, CH), 5.42 (dd, JHH = 11 Hz, JPH = 4.0 Hz, 2H, CH). 31P{1H}
NMR (162 MHz, C6D6, 19 °C): δ 32.8.
Mn[CH(CO2Me)(CH2CO2Me)](CO)5. 1H NMR (C6D6, 30 °C): δ
2.40 (dd, JHH = 17.6, 4.4 Hz, 1H, CHH), 2.67 (dd, JHH = 10.0, 4.4 Hz,
1H, CHMn), 3.27 (dd, JHH = 17.6, 10.0 Hz, 1H, CHH), 3.33 (s, 3H,
CO2Me), 3.47 (s, 3H, CO2Me).
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Fe[CH(CO2Me)Me]Cp(CO)3. H NMR (C6D6, 30 °C): δ 1.39 (d,
JHH = 7.3 Hz, 3H, Me), 2.51 (q, JHH = 7.3 Hz, 1H, CH), 3.49 (s, 3H,
CO2Me), 4.08 (s, 5H, Cp).
W[CH(CO2Me)Me]Cp*(CO)3. 1H NMR (C6D6, 30 °C): δ 1.56
(s, 15H, Me (Cp*)), 1.82 (d, JHH = 6.6 Hz, 3H, Me), 2.18 (q, JHH = 6.6
Hz, 1H, CH), 3.60 (s, 3H, CO2Me).
W[CH(CO2Et)(CH2CO2Et)]Cp(CO)3.
1H NMR (C6D6, 20 °C): δ 0.97 (t, JHH = 7.3 Hz, 3H, CH3), 1.12 (t,
JHH = 7.3 Hz, 3H, CH3), 2.64 (dd, JHH = 17.3, 3.3 Hz, 1H, CHsynH),
3.13 (dd, JHH = 17.3, 12.1 Hz, 1H, CHHanti), 3.51 (dd, JHH = 12.1,
3.3 Hz, 1H, CHW), 3.98 (q, JHH = 7.3 Hz, 2H, CO2CH2), 4.08
(m, 3H, 2H, CO2CH2), 4.58 (s, 5H, Cp). Hsyn and Hanti proton were
assigned by using the Karplus equation (see the Supporting
Synthesis of Pd(dimethyl fumarate)(PR3)2 (R = Me (3-Me), Et
(3-Et)). The synthesis of Pd(dimethyl fumarate)(PMe3)2 (3-Me) is given
as a general procedure. To a solution of Pd(methyl acrylate)(PMe3)223
(96.9 mg, 0.281 mmol) in Et2O (15 mL) was added dimethyl fumarate
(41.0 mg, 0.284 mmol) in Et2O (3 mL) at room temperature. After
removal of solvent, the brown oily residue was extracted with Et2O
(2 mL × 3). After concentration to 2 mL, the compound was crystallized
W[CH(CO2Et)(CHDCO2Et)]Cp(CO)3. 1H NMR (C6D6, 20 °C): δ
0.97 (t, JHH = 7.3 Hz, 3H, CH3), 1.12 (t, JHH = 7.3 Hz, 3H, CH3), 3.11
(d, JHH = 12.4 Hz, 1H, CDH), 3.51 (d, JHH = 12.4 Hz, 1H, CHW),
3.98 (q, JHH = 7.3 Hz, 2H, CO2CH2), 4.08 (m, 3H, 2H, CO2CH2),
4.58 (s, 5H, Cp).
X-ray Analysis. Single crystals of 4-Cy suitable for X-ray analysis
were obtained from a hexane solution. A single crystal was selected
using a polarized microscope and was mounted on a glass capillary.
The unit cell parameters and intensity data were collected using a
Bruker AXS APEXII ULTRA CCD diffractometer equipped with
a fine-focus Mo Kα X-ray source. Empirical absorption corrections
were made using the SADABS program.27 The structure was solved by
direct methods (SHELXT)28 and refined on F2 using the full-matrix
least-squares methods of SHELXL-2014.29
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to give ocher crystals in 93% yield (235.4 mg, 0.6829 mmol). H NMR
(400 MHz, C6D6, 23 °C): δ 1.03 (d, JPH = 7.2 Hz, 9H, PMe), 3.51 (s, 6H,
OMe), 4.53 (m, 2H, CH). 31P{1H} NMR (162 MHz, C6D6, 23 °C):
δ −20.8.
Pd(dimethyl fumarate)(PEt3)2 (3-Et). This complex was synthe-
23
sized from Pd(methyl acrylate)(PEt3)2 (217.8 mg, 0.5079 mmol)
and dimethyl fumarate (73.9 mg, 0.513 mmol) in 81% yield (199.4 mg,
1
0.4096 mmol). H NMR (400 MHz, C6D6, 18 °C): δ 0.89 (dt, JPH
=
15.5 Hz, JHH = 7.5 Hz, 9H, PCH2Me), 1.46 (quin., JHH = JPH = 7.5 Hz,
6H, PCH2), 3.45 (s, 6H, OMe), 4.40 (m, 2H, CH). 31P{1H} NMR
(162 MHz, C6D6, 18 °C): δ 18.0.
Satisfactory elemental analyses of Pd(dimethyl fumarate)(PR3)2
(R = Me (3-Me), Et (3-Et)) were not obtained, probably due to
their instability. They were characterized by spectroscopic methods.
Alkene Insertion into a Hydrogen−Metal Bond Assisted by
Mono(phosphine)palladium(0) Complexes. As a typical proce-
dure, the reaction of methyl acrylate with WHCp(CO)3 is given.
In an NMR tube containing 346 μL of C6D6 were placed 50.5 μL of a
0.395 M C6D6 solution of WHCp(CO)3 (0.020 mmol) and 64.0 μL of
a 0.313 M C6D6 solution of dimethyl fumarate (0.020 mmol). To this
was added a solution of triphenylmethane (0.268 M, 93.0 μL,
0.025 mmol) as an internal standard. After the addition of a C6D6
solution of Pd{η2:η2-(CH2CHCH2)2O}(PPh3) (1-Ph; 0.0194 M,
10.3 μL, 0.00020 mmol) to form a 0.04 M solution of WHCp(CO)3
DFT Calculations. Density functional theory (DFT) calcula-
tions were employed with the long-range and dispersion-corrected
ωB97X-D functional.30 The basis set consisted of the Stuttgart−
Dresden SDD effective core potential basis set on the Pd and
W atoms31 and the 6-31G(d,p) basis sets on all other atoms.32 The
effect of benzene as a solvent was included in the calculations by using
the polarizable continuum model (PCM) using the integral equation
formalism variant (IEFPCM).33 The optimized molecular structures
were verified by vibrational analysis; equilibrium structures did not
have imaginary frequencies, and transition state structures had only
one imaginary frequency corresponding to the reaction coordinate.
Additionally, intrinsic reaction coordinate (IRC) calculations34,35 were
carried out to check whether or not the transition state leads to the
reactant and the product. Relative energies were corrected by adding
the unscaled zero-point vibrational energy. All calculations were car-
ried out using the Gaussian 09 program.36
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and dimethyl fumarate, the reaction was monitored by H NMR at
1
30 °C, and the yields were periodically estimated by H NMR. This
and other insertion products were characterized by spectroscopic
methods.
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W[CH(CN)Me]Cp(CO)3. H NMR (C6D6, 30 °C): δ 1.44 (d, JHH
=
ASSOCIATED CONTENT
* Supporting Information
■
7.5 Hz, 3H, Me), 2.12 (q, JHH = 7.5 Hz, 1H, CH), 4.53 (s, 5H, Cp).
W[CH(CO2Me)Me]Cp(CO)3. 1H NMR (C6D6, 30 °C): δ 1.63 (d, JHH
= 7.3 Hz, 3H, Me), 3.06 (q, JHH = 7.3 Hz, 1H, CH), 3.46 (s, 5H,
CO2Me), 4.62 (s, 5H, Cp).
S
The Supporting Information is available free of charge on the ACS
1
W[CH(CO2Me)(CH2CO2Me)]Cp(CO)3. H NMR (C6D6, 30 °C): δ
NMR data, kinetic data and rate equations for catalytic
reactions, and DFT calculations of A−D, TS1, and TS2
2.61 (dd, JHH = 17.6, 2.8 Hz, 1H, CHH), 3.11 (dd, JHH = 17.6, 13.2 Hz,
1H, CHH), 3.36 (s, 3H, CO2Me), 3.48 (s, 3H, CO2Me), 3.48 (dd,
JHH = 13.2, 2.8 Hz, 1H, CHW), 4.56 (s, 5H, Cp).
Mo[CH(CN)Me]Cp(CO)3. 1H NMR (C6D6, 30 °C): δ 1.38 (d, JHH
=
Optimized coordinates (XYZ)
7.4 Hz, 3H, Me), 2.00 (q, JHH = 7.4 Hz, 1H, CH), 4.51 (s, 5H, Cp).
Mo[CH(CO2Me)Me]Cp(CO)3. H NMR (C6D6, 30 °C): δ 1.59 (d,
Accession Codes
1
CCDC 1565941 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: +44 1223 336033.
JHH = 7.4 Hz, 3H, Me), 2.89 (q, JHH = 7.4 Hz, 1H, CH), 3.46 (s, 5H,
CO2Me), 4.59 (s, 5H, Cp).
Mo[CH(CO2Me)(CH2CO2Me)]Cp(CO)3. H NMR (C6D6, 30 °C): δ
2.60 (dd, JHH = 16.5, 2.7 Hz, 1H, CHH), 3.19 (dd, JHH = 16.5, 12.8 Hz,
1H, CHH), 3.32 (dd, JHH = 12.8, 2.7 Hz, 1H, CHMo), 3.36 (s, 3H,
CO2Me), 3.48 (s, 3H, CO2Me), 4.52 (s, 5H, Cp).
1
H
Organometallics XXXX, XXX, XXX−XXX