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J. Yan et al. / Tetrahedron Letters 46 (2005) 8173–8175
Table 1. The results of the Suzuki reaction of sodiumtetraphenylborate with iodanes
X
Y
H O
2
Ph BNa
4
+
Ar
I
Ph Ar
R.T.
1
2
3
a
Entry
1
Iodane
Product
Yield (%)
OH
8
2a Ph
I
3a Ph–Ph
97
OTs
2b PhI(OAc)
3 2
2c PhI(OCOCF )
2d Ph–I –O–I –Ph 2BF
2e PhI@O
2
3
4
5
6
7
2
3a
3a
3a
3a
78
90
91
55
99
47
+
+
4À
b
9
2f p-MeO–C
6
H
4
I(OAc)
2
3b p-MeO–C
6
H
4
–Ph
1
0
2g p-Cl–C
6
H
4
I(OAc)
2
3c p-Cl–C
6
H
4
–Ph
OH
I
Ph
OH
11
8
2h
O
3d
90
84
C
C
O
O
OH
9
2i p-Cl-C H4
I
3c
6
OTs
a
Isolated yields.
b
The reaction was run with sodiumtetraphenylborate (2 equiv), iodosylbenzene (1 equiv) and p-TsOH (2 equiv) in water for 0.5 h.
(
entry 6), while when Ar was a phenyl with electron-
Zhejiang Province Education Foundation of China
(Project 20040569) is greatly appreciated.
withdrawing group, the yields of 3c were somewhat low-
er (entries 7 and 9) compared with 3b (entry 6) and 3a
(
entry 1), respectively. When iodosylbenzene (2e) was
treated with 1 under the same reaction conditions, the
reaction did not occur even when the reaction mixture
was stirred for a long time at room temperature or in
heating conditions, but after adding 2 equiv of p-TsOH
and stirred for 0.5 h, product 3a was obtained in 55%
References and notes
1. For recent reviews see: (a) Hassen, J.; Sevignon, M.;
Gozzi, C.; Schulz, E.; Lemaire, M. Chem. Rev. 2002, 102,
359–1470; (b) Kotha, S.; Lahiri, K.; Kashinath, D.
Tetrahedron 2002, 58, 9633–9695; (c) Suzuki, A. J.
Organomet. Chem. 1999, 576, 147–168; (d) Miyaura, N.;
Suzuki, A. Chem. Rev. 1995, 95, 2457–2483.
1
7
yield.
Iodoniumsalts have been used widely in Suzuki reac-
tions. However, few iodanes were used in place of aryl
2
3
. Leadbeater, N. E.; Marco, M. J. Org. Chem. 2003, 68,
5
660–5667.
4
a
halides and triflates in Suzuki reactions and to our
knowledge, there is no reports about catalyst- and
base-free Suzuki coupling reactions of sodiumtetraphen-
ylborate with iodanes. The mechanism was probably
. (a) Varvoglis, A. Hypervalent Iodine in Organic Synthesis;
Academic Press: London, 1997; Varvoglis, A. Tetrahedron
1997, 53, 1179–1255; (b) Stang, P. J.; Zhdankin, V. V.
Chem. Rev. 1996, 96, 1123–1178; (c) Zhdankin, V. V.;
Stang, P. J. Chem. Rev. 2002, 102, 2523–2584; (d) Wirth,
T.; Hirt, U. H. Synthesis 1999, 1271–1287; (e) Kirschning,
A. Eur. J. Org. Chem. 1998, 11, 2267–2274; (f) Ochiai, M.
In Chemistry of Hypervalent Compounds; Akibe, K., Ed.;
VCH: New York, 1999, Chapter 13, pp 359–387; Ochiai,
M. J. Organomet. Chem. 2000, 611, 494–508; (g) Oku-
yama, T. Acc. Chem. Res. 2002, 35, 12–18; (h) Zhdankin,
V. V.; Stang, P. J. Tetrahedron 1998, 54, 10927–10966; (i)
Grushin, V. V. Chem. Soc. Rev. 2000, 29, 315–324.
involved first with nucleophilic substitution of acid radical
À
of iodane by Ph B , then, an intramolecular coupling
4
reaction was accompanied to yield biaryls. The catal-
yst-free Suzuki coupling reaction without base has pro-
vided a fast and efficient method for preparation of
biaryls, it had some advantages such as mild reaction
conditions, simple procedure and good yields. Further-
more, the scope of catalyst-free Suzuki coupling reac-
tions could be extended. Further investigation of
catalyst-free Suzuki reactions will be reported in due
course.
4. (a) Kang, S.-K.; Lee, H.-W.; Jang, S.-B.; Ho, P.-S. J. Org.
Chem. 1996, 61, 4720–4724; (b) Kang, S.-K.; Yamagushi,
Y.; Kim, T.-H.; Ho, P.-S. J. Org. Chem. 1996, 61, 9082–
9
083; (c) Bumagin, N. A.; Luzikova, E. V.; Sukhomlinova,
L. I.; Tolstaya, T. P.; Beletskaya, I. P. Russ. Chem. Bull.
995, 44, 385–387; (d) Kang, S.-K.; Jung, K.-Y.; Park,
C.-H.; Jang, S.-B. Tetrahedron Lett. 1995, 36, 8047–8050;
e) Moriarty, R. M.; Epa, W. R.; Awashti, A. K. J. Am.
1
Acknowledgements
(
Financial support fromthe Zhejiang Province Natural
Science foundation of China (Project Y404016) and
Chem. Soc. 1991, 113, 6315–6317; (f) Moriarty, R. M.;
Epa, W. R. Tetrahedron Lett. 1992, 33, 4095–4098;