5 H. Yoshida, K. Tanino, J. Ohshita and A. Kunai, Angew. Chem., Int.
Ed., 2004, 43, 5052.
6 We also reported synthesis of 1,2-disubstituted arenes through insertion
reactions of arynes into a nucleophilic–electrophilic s-bond: H. Yoshida,
E. Shirakawa, Y. Honda and T. Hiyama, Angew. Chem., Int. Ed., 2002,
41, 3247; H. Yoshida, T. Terayama, J. Ohshita and A. Kunai, Chem.
Commun., 2004, 1980; H. Yoshida, M. Watanabe, J. Ohshita and
A. Kunai, Chem. Commun., 2005, 3292; H. Yoshida, T. Minabe,
J. Ohshita and A. Kunai, Chem. Commun., 2005, 3454.
7 Other catalytic transformations of arynes by use of a transition metal
complex: E. Yoshikawa and Y. Yamamoto, Angew. Chem., Int. Ed.,
2000, 39, 173; E. Yoshikawa, K. V. Radhakrishnan and Y. Yamamoto,
J. Am. Chem. Soc., 2000, 122, 7280; N. Chatani, A. Kamitani,
M. Oshita, Y. Fukumoto and S. Murai, J. Am. Chem. Soc., 2001, 123,
12686; D. Pen˜a, D. Pe´rez, E. Guitia´n and L. Castedo, Eur. J. Org.
Chem., 2003, 7, 1238, and references cited therein.
8 Biaryl synthesis via aryne intermediates: H. Hart, K. Harada and
C.-J. F. Du, J. Org. Chem., 1985, 50, 3104; A. Saednya and H. Hart,
Synthesis, 1996, 1455; H. Tomori, J. M. Fox and S. L. Buchwald, J. Org.
Chem., 2000, 65, 5334; F. Leroux and M. Schlosser, Angew. Chem., Int.
Ed., 2002, 41, 4272.
9 Y. Himeshima, T. Sonoda and H. Kobayashi, Chem. Lett., 1983, 1211.
10 A palladium–ETPO complex has been demonstrated by Tanaka to be
an efficient catalyst for disilylation, digermylation, silylboration or
stannylboration of such unsaturated organic compounds as alkynes and
alkenes: H. Yamashita, M. Catellani and M. Tanaka, Chem. Lett., 1991,
241; K. Mochida, C. Hodota, H. Yamashita and M. Tanaka, Chem.
Lett., 1992, 1635; S. Onozawa, Y. Hatanaka and M. Tanaka, Chem.
Commun., 1997, 1229; S. Onozawa, Y. Hatanaka and M. Tanaka,
Chem. Commun., 1999, 1863; S. Onozawa, Y. Hatanaka and M. Tanaka,
Tetrahedron Lett., 1998, 39, 9043.
Scheme 4 Synthesis of substituted biaryls using 3a.
cyclisation at 0 uC to produce a 73% yield of 9,9-dimethyl-9-
stannafluorene (9). On the other hand, the aryl anion could be
trapped by 4-methoxybenzaldehyde at 278 uC to afford stannyl-
substituted benzhydrol 10 as
a mixture of diastereomers
(ratio 5 59:41) in 71% yield, which was further convertible into
a dibenzopyran derivative (11) via intramolecular arylation of the
hydroxyl moiety in the presence of copper(II) chloride.18
11 The reaction using Bu3SnSnBu3 gave an only 4% yield of the respective
dimerisation–distannylation product.
12 We also examined an ETPO-type ligand bearing such a substituent as
H, Me, Ph or t-Bu at its 4-position, however, none of them improved the
yield and selectivity of 3a.
13 Other reaction conditions employed for optimisation: solvent: DME,
n-Bu2O; temperature: 0 uC, 50 uC; Pd source: Pd(dba)2, Pd(acac)2, Pd(g5-
C5H5)(g3-C3H5), [Pd(g3-C3H5)Cl]2.
14 Although we also conducted the reactions of 3-methyl or 4-methox-
ybenzyne to investigate the regioselectivity in detail, both reactions
resulted in the formation of a complex mixture.
15 Reviews: M. A. Bennett and H. P. Schwemlein, Angew. Chem., Int. Ed.
Engl., 1989, 28, 1296; M. A. Bennett and E. Wenger, Chem. Ber./Recl.,
1997, 130, 1029.
16 B. L. Edelbach, D. A. Vicic, R. J. Lachicotte and W. D. Jones,
Organometallics, 1998, 17, 4784; B. L. Edelbach, R. J. Lachicotte and
W. D. Jones, J. Am. Chem. Soc., 1998, 120, 2843; T. Satoh and
W. D. Jones, Organometallics, 2001, 20, 2916.
17 The reaction of a palladacyclopentadiene, derived from a Pd(0) complex
and 2 mol of an alkyne, with an organostannane has been demonstrated
to be a key step in the palladium-catalysed dimerisation-carbostannyla-
tion of alkynes: E. Shirakawa, H. Yoshida, Y. Nakao and T. Hiyama,
J. Am. Chem. Soc., 1999, 121, 4290; H. Yoshida, E. Shirakawa,
Y. Nakao, Y. Honda and T. Hiyama, Bull. Chem. Soc. Jpn., 2001, 74,
637.
18 Copper(II)-promoted arylation of NH-containing compounds with
organostannanes: P. Y. S. Lam, G. Vincent, D. Bonne and
C. G. Clark, Tetrahedron Lett., 2002, 43, 3091.
19 Previously reported synthesis of 2,29-distannylbiaryls: B. Schilling,
V. Kaiser and D. E. Kaufmann, Chem. Ber./Recl., 1997, 130, 923;
T. Hoshi, H. Shionoiri, M. Katano, T. Suzuki, M. Ando and
H. Hagiwara, Chem. Lett., 2002, 600; T. Hoshi, H. Shionoiri,
M. Katano, T. Suzuki and H. Hagiwara, Tetrahedron: Asymmetry,
2002, 13, 2167; A. B. Chopa, M. T. Lochhart and G. F. Silbestri,
Organometallics, 2002, 21, 5874.
In conclusion, we have disclosed the first example of an
insertion reaction of two molar amounts of arynes into an
element–element s-bond, which is efficiently catalysed by a
palladium–ETPO complex. Based upon the present reaction,
diverse 2,29-distannylbiaryls, which are hardly accessible by
conventional methods, can be obtained straightforwardly.19
Moreover, the resulting products have been demonstrated to be
convertible into variously substituted biaryls utilizing their carbon–
tin bonds. Studies on the improvement of the yield and selectivity
of products and on details of the reaction mechanism as well as on
expansion of the reaction scope are in progress.
Notes and references
1 Reviews: G. Bringmann, R. W alter and R. Weirich, Angew. Chem., Int.
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J. Hassan, M. Se´vignon, C. Gozzi, E. Schulz and M. Lemaire, Chem.
Rev., 2002, 102, 1359.
2 Biaryl synthesis via oxidative couplings: G. Bringmann and S. Tasler,
Tetrahedron, 2001, 57, 331; H. Tohma, H. Morioka, S. Takizawa,
M. Arisawa and Y. Kita, Tetrahedron, 2001, 57, 345; R. Irie,
K. Masutani and T. Katsuki, Synlett, 2000, 1433; D. S. Surry, X. Su,
D. J. Fox, V. Franckevicius, S. J. Macdonald and D. R. Spring, Angew.
Chem., Int. Ed., 2005, 44, 1870.
3 H. Yoshida, Y. Honda, E. Shirakawa and T. Hiyama, Chem. Commun.,
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4 H. Yoshida, J. Ikadai, M. Shudo, J. Ohshita and A. Kunai, J. Am.
Chem. Soc., 2003, 125, 6638; H. Yoshida, J. Ikadai, M. Shudo,
J. Ohshita and A. Kunai, Organometallics, 2005, 24, 156; J. Ikadai,
H. Yoshida, J. Ohshita and A. Kunai, Chem. Lett., 2005, 34, 56.
5680 | Chem. Commun., 2005, 5678–5680
This journal is ß The Royal Society of Chemistry 2005