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Dalton Transactions
Page 9 of 10
ARTICLE
DOI: 10.1039/C5DT01991E
Journal Name
7.12 (d, J = 3.5 Hz, 1H), 6.74 (d, J = 3.5 Hz, 1H), 2.80 (t, J = 7.5 Hz,
2H), 1.73 (sext, J = 7.4 Hz, 2H), 1.00 (t, J = 7.4 Hz, 3H). 13C NMR (100
MHz, CDCl3): δ 145.6, 141.8, 134.9, 128.9, 127.1, 125.6, 125.6,
125.2, 122.8, 32.4, 25.0, 13.8.
The geometries of the phosphines (1a
,
1d
,
1e
,
4a
,
4d and 4e
)
and their ligated Pd complexes (1-Pd,
1-Pd(dba), and 4
-Pd)
were fully optimized and characterized by frequency
calculation by ONIOM method21 at the second order Møller-
Plesset perturbation method (MP2)22 in the high-level layer
and B3LYP (Becke’s three parameter hybrid method23a using
the Lee–Yang–Parr correlation function23b) density functional
theory (DFT) in the low-level layer with the LANL2DZ basis set24
using Gaussian 09 program.25 The atom distribution in those
two layers is as follows: high level layer is the atoms being
related to the interaction with Pd, and the others are low level
layer (the details are shown in ESI). Free energies and
enthalpies (298.15 K, 1 atm) were computed for the gas phase.
NBO calculations26 were performed at the M06-2X27 with 6-
31G(d)24 and LANL2DZ with effective core potential (ECP) for
Pd. For the NBO energetic analysis, NBO deletions were
employed using $DEL Keylist.28
2-(4-Methylphenyl)-5-propylthiophene18
The direct arylation of 2-propylthiophene (50 μL, 0.39 mmol) with
4-bromotoluene (54.97 mg, 0.32mmol) were conducted using
Pd(OAc)2 (0.72 mg, 3.21 μmol), 1a (4.32 mg, 6.42 μmol), K2CO3
(66.63 mg, 0.48 mmol), PivOH (9.85 mg, 0.096 mmol) and DMA (1.1
mL) by the general procedure to give 2-(4-methylphenyl)-5-
1
propylthiophene as a colorless oil (56.53 mg, 81% yield). H NMR
(400 MHz, CDCl3): δ 7.44 (d, J = 8.2 Hz, 2H), 7.14 (d, J = 8.0 Hz, 2H),
7.06 (d, J = 3.6 Hz, 1H), 6.72 (d, J = 3.5 Hz, 1H), 2.78 (t, J = 7.7 Hz,
2H), 2.34 (s, 3H), 1.71 (sext, J = 7.5 Hz, 2H), 0.99 (t, J = 7.4 Hz, 3H).
13C NMR (100 MHz, CDCl3): δ 145.0, 142.0, 136.9, 132.1, 129.6,
125.5, 125.1, 122.2, 32.4, 25.0, 21.3, 13.9.
2-Methyl-5-{4-(trifluoromethyl)phenyl}thiophene20
The direct arylation of 2-methylthiophene (37.5 μL, 0.39 mmol) with
4-bromobenzotrifluoride (45μL, 0.32mmol) were conducted using
Pd(OAc)2 (0.72 mg, 3.21 μmol), 1a (4.32 mg, 6.42 μmol), K2CO3
(66.63 mg, 0.48 mmol), PivOH (9.85 mg, 0.096 mmol) and DMA (1.1
mL) by the general procedure to give 2-methyl-5-{4-
(trifluoromethyl)phenyl}thiophene as a white solid (69.84 mg, 90%
Acknowledgements
The acknowledgements come at the end of an article after the
conclusions and before the notes and references.
1
yield). H NMR (400 MHz, CDCl3): δ 7.65 – 7.56 (m, 4H), 7.20-7.18
(m, 1H), 6.77 - 6.75 (m, 1H), 2.52 (s, 3H). 13C NMR (100 MHz, CDCl3):
δ 141.3, 140.3, 138.2, 129.5 – 128.2 (m), 126.7, 126.0 (q, J = 3.8 Hz),
125.5, 124.5, 124.4 (q, J = 270.0 Hz), 15.7. 19F NMR (376 MHz,
CDCl3): δ -63.6 (s).
Notes and references
1
2
3
Phosphorus(III)Ligands in Homogeneous Catalysis: Design
and Synthesis, ed. P. C. J. Kamer and P. W. N. M. van
Leeuwen, Willey-VCH, Weinheim, Germany, 2012.
Review for fluorinated aryl phosphines: C. L. Pollock, G. C.
Saunders, E. C. M. S. Smyth and V. I. Sorokin, J. Fluorine
Chem., 2008, 129, 142.
(a) T. Korenaga, K. Osaki, R. Maenishi and T. Sakai, Org. Lett.,
2009, 11, 2325; (b) T. Korenaga, K. Abe, A. Ko, R. Maenishi
and T. Sakai, Organometallics, 2010, 29, 4025; (c) T.
Korenaga, A. Ko, K. Uotani, Y. Tanaka and T. Sakai, Angew.
Chem. Int. Ed., 2011, 50, 10703.
2-{4-(Trifluoromethyl)phenyl}benzo[b
]thiophene12b
The direct arylation of 2-methylthiophene (37.5 μL, 0.39 mmol) with
4-bromobenzotrifluoride (45μL, 0.32mmol) were conducted using
Pd(OAc)2 (0.72 mg, 3.21 μmol), 1a (4.32 mg, 6.42 μmol), K2CO3
(66.63 mg, 0.48 mmol), PivOH (9.85 mg, 0.096 mmol) and DMA (1.1
mL)
by
the
general
procedure
to
give
2-{4-
(trifluoromethyl)phenyl}benzo[b]thiophene as a white solid (77.55
1
4
(a) T. Korenaga, R. Maenishi, K. Hayashi and T. Sakai, Adv.
Synth. Catal., 2010, 352, 3247. (b) T. Korenaga, K. Hayashi, Y.
Akaki, R. Maenishi and T. Sakai, Org. Lett., 2011, 13, 2022; (c)
mg, 87% yield). H NMR (400 MHz, CDCl3): δ 7.87 – 7.79 (m, 4H),
7.67 (d, J = 8.2 Hz, 2H), 7.64 (s, 1H), 7.41 – 7.33 (m, 2H). 13C NMR
(100 MHz, CDCl3): δ 142.4, 140.5, 139.9, 137.9, 131- 129.0 (m),
126.8, 126.2 – 126.0 (m), 125.1, 125.0, 124.1 (q, J = 270.4 Hz),
124.1, 122.5, 121.2. 19F NMR (376 MHz, CDCl3): δ -63.8 (s).
T. Korenaga, A. Ko and K. Shimada, J. Org. Chem., 2013, 78
9975.
,
5
6
T. Korenaga, N. Suzuki, M. Sueda and K. Shimada, J.
Organomet. Chem., 2015, 780, 63.
Reviews: (a) D. S. Surry and S. L. Buchwald, Chem. Sci., 2011,
2
Ed., 2008, 47, 6338.
, 27; (b) D. S. Surry and S. L. Buchwald, Angew. Chem. Int.
Evaluation of Kinetic Isotope Effect
A 10 mL Schlenk flask was flushed with argon and charged with
K2CO3 (66.63 mg, 0.48 mmol), PivOH (9.84 mg, 0.096 mmol)
and DMA (1.1 mL). The mixture was stirred at room
temperature for 30 min., and then Pd(OAc)2 (0.72 mg, 3.21
μmol), 1a (4.32 mg, 6.42 μmol), 4-bromobenzotrifluoride (4.5
μL, 0.032mmol) and the 1 : 1 mixture of 2-propylthiophene
and 2-propylthiophene-d (42 μL, 3.21 mmol) were added. The
resulting mixture was stirred at 100 °C for 20 min. The reaction
mixture was then poured into water and extracted with Et2O.
The organic layer were dried over Na2SO4 and concentrated
under reduced pressure. The KIE is calculated by 1H NMR.
7
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Computational methods
8 | J. Name., 2012, 00, 1-3
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