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P. Wang et al. / Journal of Catalysis 361 (2018) 230–237
Table 4
4. Experimental section
4.1. Reagents and analysis
The crystal data and structure refinement for L2.
L2
Empirical formula
Formula weight
Crystal system
Space group
a(Å)
C
15H13N2PS
The reagents used in this work were purchased from Shanghai
Aladdin Chemical Reagent Co. Ltd. and Acros China, and used as
received if not specified. THF (tetrahydrofuran) was dried and dis-
tilled over sodium/benzophenone. Dichloromethane (CH2Cl2) was
dried over CaH2. All preparation procedures were carried out under
nitrogen atmosphere, using Schlenk and vacuum line techniques.
The 1H, 13C and 31P NMR spectra were recorded on a Bruker Avance
400 spectrometer. The 31P NMR spectra were referenced to 85%
H3PO4 sealed in a capillary tube as an internal standard. Gas chro-
matography (GC) was performed on a SHIMADZU-2014 equipped
284.30
Monoclinic
P2(1)/n
7.7253(3)
11.7296(4)
16.0249(6)
90
103.5030(10)
90
1411.95(9)
4
1.337
0.329
173(2)
0.71073
16,051
2484 [Rint = 0.0413]
0.0514
0.1230
592
b (Å)
c (Å)
a
(o)
b(o)
c
(o)
V (Å3)
Z
dcalc (g cmꢀ3
)
l
(Mo-K ) (mmꢀ1
)
a
with a DM-Wax capillary column (30 m ꢃ 0.25 mm ꢃ 0.25
lm).
T (K)
k(Å)
GC-mass spectrometry (GC-MS) was recorded on an Agilent 6890
instrument equipped with an Agilent 5973 mass selective detector.
Total reflections
Unique reflections (Rint
R1 [I > 2 (I)]
)
r
4.2. Synthesis
wR2 (all data)
F(0 0 0)
Goodness-of-fit on F2
1.065
L1 and L2 were prepared according to the procedures reported
by Braunstein [31] and Woollins [43,44] respectively with some
modifications. TG/DTG analyses in air flow for the phosphines (L1
and L2) are available in supporting information.
positions and refined isotropically. The crystal data and refinement
details are given in Table 4.
4.2.1. N-(Diphenylphosphino)-4,5-dihydrothiazol-2-amine (L1)
Under N2 atmosphere, a mixture of 2-amino-2-thiazoline (1.02
g, 10.0 mmol) and triethylamine (2.02 g, 20.0 mmol) in dry CH2Cl2
4.4. Computational methods
(50 mL) was treated dropwise with
a
suspension of
diphenylchlorophosphine (2.21 g, 10.0 mmol, 1.0 equiv) in CH2Cl2
(3 mL). Upon stirred vigorously at room temperature for 48 h,
the obtained reaction mixture was stripped of the solvent on a
rotary evaporator. The residue was then dissolved in THF (50
mL). Upon filtration the clear filtrates were dried in vacuo. The
obtained residue was washed by acetone and dried to afford L1
as a white solid (2.21 g, yield 92%). 1H NMR (d, ppm, CDCl3):
7.85–7.80 (m, 4H), 7.44–7.39 (m, 6H), 3.74 (t, 2H, J = 8.0 Hz), 3.28
(t, 2H, J = 8.0 Hz). 31P NMR (d, ppm, CDCl3): 25.26 (s).
The DFT calculation was carried out using the Gaussian 09 soft-
ware package [45]. The geometric structures of A, A’, I, I’ and E in
Scheme 2 were optimized using the M06 functional [46,47] com-
bined with the Lanl2dz [48,49] and 6-31G* basis sets [50], denoted
as the M06/Lanl2dz+6-31G* method. The Lanl2dz basis set com-
bined with the relativistic effective core potential [48,49] was used
to describe the metal element Rh and the 6-31G* basis set was uti-
lized to describe the non-metallic elements C, N, O, S, P and H. The
solvent effect of methanol was evaluated using the SMD [51]
model at the same computational level, with the dielectric con-
4.2.2. N-(Diphenylphosphino)thiazol-2-amine (L2)
stant epsilon of methanol being 31.2. The free energy
DG was cal-
culated in the unit of kcal molꢀ1 and at the temperature 298 K,
including the solvation correction evaluated from the SMD model.
The Cartesian coordinates of optimized structures of A, A’, I, I’ and
E can be found in ESI.
Under N2 atmosphere, a mixture of 2-aminethiazol (1.00 g, 10.0
mmol, 1.0 equiv) and triethylamine (2.02 g, 20.0 mmol, 2.0 equiv)
in CH2Cl2 (50 mL) was treated dropwise with a suspension of
diphenylchlorophosphine (2.21 g, 10.0 mmol, 1.0 equiv) in CH2Cl2
(3 mL) at -20 °C. The obtained mixture was stirred vigorously at -
20 °C for 20 h and then warmed to room temperature naturally.
After removal of the solvent in vacuo, the residue was purified
by silica column chromatography, using CH2Cl2/MeOH (20:1 and
10:1) as an eluent, to yield L2 as a white solid (2.67 g, yield 94%).
The sample suitable for single crystal X-ray diffraction analysis
was recrystallized in CH2Cl2/ether. 1H NMR (d, ppm, CDCl3): 8.97
(d, 1H, J = 4.0 Hz), 7.49–7.39 (m, 4H), 7.41–7.39 (m, 6H), 7.11 (t,
1H, J = 4.0 Hz), 6.82 (d, 1H, J = 4.0 Hz). 31P NMR (d, ppm, CDCl3):
41.14 (s).
4.5. General procedures for tandem methoxycarbonylation-aminolysis
of olefins in alcohols
In a typical experiment for reactions of olefins with CO and NH3,
the commercial Rh(acac)(CO)2 (0.005 mmol), the isolated L1 (0.03
mmol), HBF4 (0.03 mmol) were added into methanol (3 mL, or the
other alcohol) and 2,5-dihydrofuran (5 mmol, or the other olefin)
sequentially. The obtained mixture in a 50 mL Teflon-lined stain-
less steel autoclave was sealed and pressured by NH3 to 0.4 MPa
then CO 4.0 MPa. The reaction mixture was stirred vigorously at
the appointed temperature for some time. Upon completion, the
autoclave was cooled down to room temperature and depressur-
ized carefully. The reaction solution was analysed by GC to deter-
mine the conversions (n-dodecane as internal standard) and the
product selectivities (normalization method) calibrated by the
authentic samples, and the products were further identified by
GC-MS.
4.3. X-ray crystallography
The crystal data for L2 was collected on a Bruker SMARTAPEX II
diffractometer using graphite monochromated Mo-K radiation (k
a
= 0.71073 Å). Data reduction included absorption corrections by
the multi-scan method. The structures were solved by direct meth-
ods and refined by full matrix least-squares using SHELXS-97
(Sheldrick, 1990), with all non-hydrogen atoms refined anisotrop-
ically. Hydrogen atoms were added at their geometrically ideal