ORGANIC
LETTERS
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Vol. XX, No. XX
000–000
Rhodium-Catalyzed Decarbonylative CꢀH
Arylation of 2‑Aryloxybenzoic Acids
Leading to Dibenzofuran Derivatives
Shinji Maetani, Takahide Fukuyama,* and Ilhyong Ryu*
Department of Chemistry, Graduate School of Science, Osaka Prefecture University,
Sakai, Osaka 599-8531, Japan
fukuyama@c.s.osakafu-u.ac.jp; ryu@c.s.osakafu-u.ac.jp
Received April 20, 2013
ABSTRACT
Rhodium-catalyzed intramolecular CꢀH arylation of 2-aryloxybenzoic acids proceeded accompanied by decarbonylation to give dibenzofuran
derivatives in high yields. The present reaction is widely applicable to substrates bearing various functionalities.
Dibenzofurans have attracted considerable attention in
biological and material sciences with wide ranging phar-
maceutical activities as well as optical and electronic
properties.1 Thus, a number of synthetic strategies have
been reported for the construction of these ring systems.2
Among the repertoire of methods for the synthesis of
dibenzofurans, palladium-catalyzed intramolecular cycliza-
tion reactions have emerged as promising methods for the
synthesis of structurally diverse dibenzofurans, including
intramolecular CꢀH arylation of 1-halo-2-phenoxybenzenes,3
dehydrogenative cyclization of diphenyl ethers,4 and oxi-
dative CꢀO cyclization of 2-arylphenols.5
The use of carboxylic acids as a carbon source for transition-
metal-catalyzed reactions is a rapidly growing area of
research.6,7 Recently, Crabtree8 and Glorius9 indepen-
dently reported the palladium-catalyzed decarboxylative
CꢀH arylation of ortho-aryloxybenzoic acids (Scheme 1,
eq 1). However, this type of reaction requires large amounts
of silver salts as oxidants and high loadings (15 mol %) of
the palladium catalyst.9 A recent report from the Shen
group also employed a palladium-catalyzed decarboxyla-
tive cyclization. In this case, bromoarenes are used for the
secondary reaction site and bromine serves as the leaving
(1) (a) Tsang, K. Y.; Diaz, H.; Graciani, N.; Kelly, J. W. J. Am.
Chem. Soc. 1994, 116, 3988. (b) Asakawa, M.; Ashton, P. R.; Brown,
C. L.; Fyfe, M. C. T.; Menzer, S.; Pasini, D.; Scheuer, C.; Spencer, N.;
Stoddart, J. F.; White, A. J. P.; Williams, D. J. Chem.;Eur. J. 1997, 3,
1136. (c) Kaniwa, K.; Ohtsuki, T.; Yamamoto, Y.; Ishibashi, M.
Tetrahedron Lett. 2006, 47, 1505. (d) Ye, Y. Q.; Koshino, H.; Onose,
J.; Yoshikawa, K.; Abe, N.; Takahashi, S. Org. Lett. 2009, 11, 5074.
(e) Teng, H.; Thakur, G. A.; Makriyannis, A. Bioorg. Med. Chem. Lett.
2011, 21, 5999. (f) Chizzali, C.; Beerhues, L. Beilstein J. Org. Chem. 2012,
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(b) Liegault, B.; Lee, D.; Huestis, M. P.; Stuart, D. R.; Fagnou, K.
J. Org. Chem. 2008, 73, 5022.
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Liu, L. J. Am. Chem. Soc. 2011, 133, 9250. (b) Wei, Y.; Yoshikai, N. Org.
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(6) For recent reviews, see: (a) Goossen, L. J.; Rodrıguez, N.;
Goossen, K. Angew. Chem., Int. Ed. 2008, 47, 3100. (b) Rodrıguez, N.;
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P. P.; Goossen, L. J. Chem. Sci. 2012, 3, 2671.
(7) For our work on transition-metal-catalyzed decarbonylative
olefin formation of aliphatic carboxylic acids, see: (a) Maetani, S.;
Fukuyama, T.; Suzuki, N.; Ishihara, D.; Ryu, I. Organometallics 2011,
30, 1389. (b) Maetani, S.; Fukuyama, T.; Suzuki, N.; Ishihara, D.; Ryu,
I. Chem. Commun. 2012, 48, 2552.
(2) (a) Sierakowski, A. F. Aust. J. Chem. 1983, 36, 1281. (b) Eisch,
J. J.; Hallenbeck, L. E.; Han, K. I. J. Am. Chem. Soc. 1986, 108, 7763.
(c) Yamato, T.; Hideshima, C.; Prakash, G. K. S.; Olah, G. A. J. Org.
Chem. 1991, 56, 3192. (d) Wassmundt, F. W.; Pedemonte, R. P. J. Org.
Chem. 1995, 60, 4991. (e) Black, M.; Cadogan, J. I. G.; McNab, H. Org.
Biomol. Chem. 2010, 8, 2961. (f) Lockner, J. W.; Dixon, D. D.; Risgaard,
R.; Baran, P. S. Org. Lett. 2011, 13, 5628. (g) Zhao, J.; Wang, Y.; He, Y.;
Liu, L.; Zhu, Q. Org. Lett. 2012, 14, 1078. (h) Zhao, J.; Zhang, Q.; Liu,
L.; He, Y.; Li, J.; Li, J.; Zhu, Q. Org. Lett. 2012, 14, 5362.
(8) Voutchkova, A.; Coplin, A.; Leadbeater, N. E.; Crabtree, R. H.
Chem. Commun. 2008, 6312.
(9) Wang, C.; Piel, I.; Glorius, F. J. Am. Chem. Soc. 2009, 131, 4194.
(3) (a) Ames, D. E.; Opalko, A. Tetrahedron 1984, 40, 1919. (b) Liu,
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10.1021/ol4010905
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