LETTER
Palladium-Catalyzed One-Pot Cross-Coupling of Phenols
2245
Z.; Wang, B.; Mo, X.-B.; Wang, Y.-Y.; Chen, P.-J.
J. Fluorine Chem. 2011, 132, 982.
(15) General Procedure for the Suzuki–Miyaura Coupling of
Phenols 1 (Table 2)
Acknowledgment
This work was supported by KAKENHI (No. 19890182) from
MEXT (Japan).
An oven-dried 10 mL test tube was evacuated and backfilled
with nitrogen. The test tube was charged with phenol 1
(0.50 mmol, 1.0 equiv), boronic acid 3 (0.75 mmol, 1.5
equiv or 1.5 mmol, 3.0 equiv), Cs2CO3 (1.5 mmol, 3.0
equiv), Pd2(dba)3 (0.0050 mmol, 1.0 mol%), and SPhos
(0.010 mmol, 2.0 mol%). The test tube was sealed with a
septum, evacuated, then backfilled with nitrogen (this
sequence was repeated three times). To the test tube were
added dry MeCN (0.50 M) and NfF (0.75 mmol, 1.5 equiv)
via a syringe in this order using a nitrogen balloon, and then
the reaction mixture was stirred at 60 °C for several hours.
After cooling the reaction mixture to r.t., EtOAc (ca. 1.0 mL)
was added. The mixture was filtered through a Celite cake,
and the filtrate was concentrated under reduced pressure.
The crude material was purified by column chromatography
on silica gel to give the biaryl 4.
Supporting Information for this article is available online at
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References and Notes
(1) For reviews, see: (a) Handbook of Organopalladium
Chemistry for Organic Synthesis; Negishi, E.; de Meijere,
A., Eds.; Wiley: New York, 2002. (b) Metal-Catalyzed
Cross-Coupling Reactions; de Meijere, A.; Diederich, F.,
Eds.; Wiley-VCH: Weinheim, 2004. (c) Johansson
Seechurn, C. C. C.; Kitching, M. O.; Colacot, T. J.;
Snieckus, V. Angew. Chem. Int. Ed. 2012, 51, 5062.
(2) (a) Littke, A. F.; Fu, G. C. Angew. Chem. Int. Ed. 2002, 41,
4176. (b) Martin, R.; Buchwald, S. L. Acc. Chem. Res. 2008,
41, 1461. (c) Fu, G. C. Acc. Chem. Res. 2008, 41, 1555.
(3) For selected reviews, see: (a) Stang, P. J.; Hanack, M.;
Subramanian, L. R. Synthesis 1982, 85. (b) Ritter, K.
Synthesis 1993, 735.
General Procedure for the Sonogashira Coupling of
Phenols 1 (Table 3)
An oven-dried 10 mL test tube was evacuated and backfilled
with nitrogen. The test tube was charged with phenol 1 (0.50
mmol, 1.0 equiv), Cs2CO3 (1.5 mmol, 3.0 equiv),
[PdCl2(MeCN)2] (0.0050 mmol, 1.0 mol%), and XPhos
(0.010 mmol, 2.0 mol%). The test tube was sealed with a
septum, evacuated, then backfilled with nitrogen (this
sequence was repeated three times). To the test tube were
added dry MeCN (0.50 M), phenylacetylene (5, 1.5 mmol,
3.0 equiv), and NfF (0.75 mmol, 1.5 equiv) via a syringe in
this order using a nitrogen balloon, and then the reaction
mixture was stirred at 60 °C for 5 h. After cooling the
reaction mixture to r.t., EtOAc (1 mL) was added. The
mixture was filtered through a Celite cake, and the filtrate
was concentrated under reduced pressure. The crude
material was purified by column chromatography on silica
gel to give the diarylacetylene 6.
(4) For selected reviews, see: (a) Vorbrüggen, H. Synthesis
2008, 1165. (b) Högermeier, J.; Reissig, H.-U. Adv. Synth.
Catal. 2009, 351, 2747.
(5) Li, B.-J.; Yu, D.-G.; Sun, C.-L.; Shi, Z.-J. Chem.–Eur. J.
2011, 17, 1728.
(6) So, C. M.; Kwong, F. Y. Chem. Soc. Rev. 2011, 40, 4963.
(7) (a) Ackermann, L.; Mulzer, M. Org. Lett. 2008, 10, 5043.
(b) Yu, D.-G.; Li, B.-J.; Zheng, S.-F.; Guan, B.-T.; Wang,
B.-Q.; Shi, Z.-J. Angew. Chem. Int. Ed. 2010, 49, 4566.
(c) Chen, G.-J.; Huang, J.; Gao, L.-X.; Han, F.-S. Chem.–
Eur. J. 2011, 17, 4038. (d) Yu, D.-G.; Shi, Z.-J. Angew.
Chem. Int. Ed. 2011, 50, 7097. (e) Ackermann, L.; Pospech,
J.; Potukuchi, H. K. Org. Lett. 2012, 14, 2146.
(8) For direct couplings of related aromatic compounds with
hydroxyl groups, see: (a) Kang, F.-A.; Sui, Z.; Murray, W.
V. J. Am. Chem. Soc. 2008, 130, 11300. (b) Luo, Y.; Wu, J.
Tetrahedron Lett. 2009, 50, 2103. (c) Luo, Y.; Wu, J.
Tetrahedron 2009, 65, 6810. (d) Čerňová, M.; Pohl, R.;
Klepetářová, B.; Hocek, M. Synlett 2012, 23, 1305.
(9) (a) Zimmer, R.; Webel, M.; Reißig, H.-U. J. Prakt. Chem.
1998, 340, 274. (b) Lyapkalo, I. M.; Vogel, M. A. K. Angew.
Chem. Int. Ed. 2006, 45, 4019. (c) Ikawa, T.; Nishiyama, T.;
Nosaki, T.; Takagi, A.; Akai, S. Org. Lett. 2011, 13, 1730.
(10) Rottländer, M.; Knochel, P. J. Org. Chem. 1998, 63, 203.
(11) Barder, T. E.; Walker, S. D.; Martinelli, J. R.; Buchwald, S.
L. J. Am. Chem. Soc. 2005, 127, 4685.
Procedure for the Stille Coupling of 4-
Hydroxyacetophenone (1c, Scheme 2)
An oven-dried 10 mL test tube was evacuated and backfilled
with argon. The test tube was charged with LiCl (46 mg,
1.5 mmol) and evacuated overnight with heating at 150 °C.
After cooling, the test tube was backfilled with argon. The
test tube was charged with 4-hydroxyacetophenone (1c, 68
mg, 0.50 mmol), Cs2CO3 (240 mg, 0.75 mmol), and
PdCl2(PPh3)2 (7.0 mg, 0.0056 mmol). The test tube was
sealed with a septum, evacuated, then backfilled with argon
(this sequence was repeated three times). To the test tube
were added dry DMF (1.0 mL, 0.50 M), tributylvinyltin (7,
61 mg, 0.65 mmol), and NfF (0.13 mL, 0.75 mmol) via a
syringe in this order using an argon balloon, then the reaction
mixture was stirred at 60 °C for 6 h. After cooling, H2O was
added to the reaction mixture. The reaction mixture was
extracted with Et2O, and the resulting aqueous layer was
extracted twice with Et2O. The combined organic layers
were washed with a sat. aq NaCl solution and dried over
anhyd Na2SO4. The solution was filtered through a glass
filter, then the filtrate was concentrated under reduced
pressure. The crude product was purified by flash column
chromatography on silica gel (hexane–EtOAc = 50:1) to
give 4-vinylacetophenone (8, 64 mg, 87%) as a colorless
solid.
(12) Using Ph3P instead of SPhos, a similar reaction of electron-
donating phenol 1b with 3a provided only 23% NMR yield
of biaryl 4b accompanied by the formation of nonaflate 2b
(77% NMR yield). Accordingly, we have concluded that
SPhos is the better ligand for the one-pot Suzuki–Miyaura
coupling, and Ph3P, which is much less expensive than
SPhos, may be an alternative in some cases.
(13) For details, see Supporting Information.
(14) For selected examples, see: (a) Echavarren, A. M.; Stille, J. K.
J. Am. Chem. Soc. 1987, 109, 5478. (b) Oh-e, T.; Miyaura,
N.; Suzuki, A. J. Org. Chem. 1993, 58, 2201. (c) Louie, J.;
Driver, M. S.; Hamann, B. C.; Hartwig, J. F. J. Org. Chem.
1997, 62, 1268. (d) Rottländer, M.; Knochel, P. J. Org.
Chem. 1998, 63, 203. (e) Zhang, X.; Sui, Z. Tetrahedron
Lett. 2003, 44, 3071. (f) Gallagher, W. P.; Maleczka, R. E.
Jr. J. Org. Chem. 2003, 68, 6775. (g) Anderson, K. W.;
Mendez-Perez, M.; Priego, J.; Buchwald, S. L. J. Org.
Chem. 2003, 68, 9563. (h) Peng, A.-Y.; Chen, B.-T.; Wang,
Procedure for the Buchwald–Hartwig Reaction of p-
Methoxyphenol (1b, Scheme 3)
An oven-dried 10 mL test tube was evacuated and backfilled
with argon. The test tube was charged with 4-methoxy-
phenol (1b, 62 mg, 0.50 mmol), aniline (9, 61 mg, 0.65
© Georg Thieme Verlag Stuttgart · New York
Synlett 2012, 23, 2241–2246