3476
Q. Tang, R. Gianatassio / Tetrahedron Letters 51 (2010) 3473–3476
Table 2 (continued)
Entry
Ar-B(OH)2
Ligand
XPhos
Products
Yield
56
N
N
O
O
BocN
B
N
N
BocN
10
a
Reaction conditions: 1-phenyl-5-chlorotetrazole (1.0 equiv), boronic acid/ester (1.1 equiv), base (3 equiv), n-butanol/H2O (3:1) (2 mL/mmol of halide), 5% (Pd(OAc)2, 10%
ligand, 150 °C, 30 min. microwave.
b
K3PO4 was used.
Cs2CO3 was used.
c
7. (a) Guram, A. S.; Wang, X.; Bunel, E. E.; Faul, M. M.; Larsen, R. D.; Martinelli, M.
Acknowledgments
J. J. Org. Chem. 2007, 72, 5104–5112; (b) Guram, A. S.; King, A. O.; Allen, J. G. Org.
Lett 2006, 8, 1787–1789.
The authors thank Jeremy Green and Anne-Laure Grillot for
valuable advice on preparation of this manuscript and Nigel Ewing
for help in generating HRMS data.
8. Zapf, A.; Ehrentraut, A.; Beller, M. Angew Chem., Int. Ed. 2000, 39, 4153–4155.
9. Zhang, C.; Huang, J.; Trudell, M. L.; Nolan, S. P. J. Org. Chem. 1999, 64, 3804–
3805.
10. Kataoka, N.; Shelby, Q.; Stambuli, J. P.; Hartwig, J. F. J. Org. Chem. 2002, 67,
5553–5566.
11. Barder, T. E.; Walker, S. D.; Martinelli, J. R.; Buchwald, S. L. J. Am. Chem. Soc.
2005, 127, 4685–4696.
References and notes
12. Experimental procedure:
A mixture of 1-phenyl-5-chlorotetrazole (180 mg,
1. (a) Miyaura, N. Top. Curr. Chem. 2002, 219, 11–59; (b) Kotha, S.; Lahiri, K.;
Kashinath, D. Tetrahedron 2002, 58, 9633–9695.
2. (a) Bellina, F.; Caprita, A.; Rossi, R. Synthesis 2004, 15, 2419–2440; (b) Martin,
R.; Buchwald, S. L. Acc. Chem. Res. 2008, 41, 1461–1473.
3. (a) Itoh, T.; Mase, T. Tetrahedron Lett. 2005, 46, 3573–3577; (b) Thompson, A. E.;
Hughes, G.; Batsanov, A. S.; Bryce, M. R.; Parry, P. R.; Tarbit, B. J. Org. Chem.
2005, 70, 388–390.
4. (a) Herr, R. J. Bioorg. Med. Chem. 2002, 10, 3379–3393; (b) Myznikov, L. V.;
Koldobskii, G. I. Chem. Heterocycl. Compd. 2007, 43, 1–9.
1 mmol), boronic acid (168 mg, 1.1 mmol), Pd(OAc)2 (11 mg, 0.05 mmol),
SPhos (41 mg, 0.1 mmol), and K3PO4 (636 mg, 3 mmol) in n-butanol (1.5 mL)
and water (0.5 mL) was purged with N2 for 10 min and was heated to 150 °C by
microwave for 10–30 minutes. The reaction mixture was diluted in EtOAc,
washed with H2O and brine, dried over sodium sulfate, filtered, and
concentrated in vacuo. The crude mixture was purified by flash
chromatography to afford the desired product. 1H NMR (500 MHz, CDCl3) 7.7
(dd, 1H), 7.55 (t, 1H), 7.49–7.50 (m, 3H), 7.32–7.43 (m, 2H), 7.15 (t, 1H), 6.88 (d,
1H). 13C NMR (500 MHz, CDCl3) 156.61, 152.11, 135.51, 133.14, 131.42, 129.91,
123.43, 123.11, 122.71, 121.13, 115.44, 113.32, 111.52, 54.84. FIA MS: m/z =
253.11 as [M+1] peak.
5. (a) Walker, S. D.; Barder, T. E.; Martinelli, J. R.; Buchwald, S. L. Angew. Chem., Int.
Ed. 2004, 43, 1871–1876; (b) Cho, S. D.; Kim, H. K.; Yim, H. S.; Kim, M. R.; Lee, J.
K.; Kim, J. J.; Yoon, Y. J. Tetrahedron 2007, 63, 1345–1352.
6. Littke, A. F.; Fu, G. C. J. Am. Chem. Soc. 2000, 122, 4020–4028.