a
Table 2 Nitration of different arylboronic acids
2-Nitronaphthalene was synthesized from the parent boronic
acid in 76% yield (Table 2, entry 4). In addition, the more
sterically demanding 1-naphthaleneboronic acid furnished
1
-nitronaphthalene in 75% isolated yield (Table 2, entry 3).
More interestingly, functionalized arylboronic acids also gave
the desired products smoothly. Hence, 4-phenoxy- and
Entry
1
Nitroarene
Isolated yield [%]
87
4
-methoxy-functionalized nitrobenzenes were isolated from
the corresponding arylboronic acids without any problem in
5
1
8
7–62% yield (Table 2, entries 6 and 7). Furthermore,
-fluoro- and 1-bromo-4-nitrobenzenes were produced in
5% and 73% successfully from 4-fluoro- and 4-bromophenyl-
boronic acid (Table 2, entries 8 and 9). Finally, 4-nitrobenzal-
dehyde was synthesized in 45% yield from the corresponding
arylboronic acid (Table 2, entry 10). Notably, in the last two
reactions the addition of 1 equiv. of boric acid is necessary in order
to get satisfying yields. Because of the electron-withdrawing
substituents on the arylboronic acid an additional activation
of the alkyl nitrite by acid seems necessary.
2
3
56
68
Unfortunately, so far the nitration protocol does not work
by applying vinyl- and hydroxy-decorated phenylboronic
acids. Similarly, pyridinyl- and quinolinylboronic acid gave
only the deborylation products. On the other hand using
4
75
3
-thiophenylboronic acid gave 10–15% of the nitro compound
without further optimization.
5
6
76
57
In conclusion, a novel methodology for the nitration of
various arylboronic acids has been established. Notably, using
inexpensive tert-butyl nitrite different nitroarenes are produced in
moderate to good yields (45–87%). Advantages of this procedure
are the operational simplicity and no need of expensive catalyst
systems.
7
8
9
62
85
Notes and references
1
(a) N. Ono, The Nitro Group in Organic Synthesis, Wiley-VCH,
New York, 2001; (b) G. K. S. Prakash and T. Mathew, Angew.
Chem., Int. Ed., 2010, 49, 1726.
2
For selected recent applications of nitroarenes in organic synthesis
see: (a) E. Byun, B. Hong, K. A. De Castro, M. Lim and H. Rhee,
J. Org. Chem., 2007, 72, 9815; (b) F. Ragaini, A. Rapetti,
E. Visentin, M. Monzani, A. Caselli and S. Cenini, J. Org. Chem.,
b
73
2
006, 71, 3748; (c) H. Zhu, X. Ke, X. Yang, S. Sarina and H. Liu,
Angew. Chem., Int. Ed., 2010, 49, 9657; (d) A. Corma,
P. Concepcion and P. Serna, Angew. Chem., Int. Ed., 2007,
6, 7266; (e) C. Tang, L. He, Y. Liu, Y. Cao, H. He and K. Fan,
b
45
´
10
4
Chem.–Eur. J., 2011, 17, 7172; (f) C. Lee and S. Liu, Chem.
Commun., 2011, 47, 6981; (g) Q. Peng, Y. Zhang, F. Shi and
Y. Deng, Chem. Commun., 2011, 47, 6476.
3 (a) W. E. Muller, The Benzodiazepine Receptor, Cambridge University
Press, New York, 1988; (b) M. Belciug and V. S. Ananthanarayanan,
J. Med. Chem., 1994, 37, 4392.
a
Arylboronic acid (1 mmol), tert-butyl nitrite (10 mmol), dioxane
b
(2 ml), 80 1C, 16 h, air, yield is based on arylboronic acid. B(OH)
1 mmol) as additive.
3
(
4
5
H. Zollinger, Color Chemistry, Wiley-VCH, New York, 1987, p. 161.
F.-R. F. Fan, Y. Yao, L. Cai, L. Cheng, J. M. Tour and A. J. Bard,
J. Am. Chem. Soc., 2004, 37, 4392.
K. Weissermel and H.-J. Arpe, Industrial Organic Chemistry,
Wiley-VCH, 4.th Edn, 2003.
activation of the alkyl nitrite by the boronic acid. Related
nitrosations are known for the reaction of arylmetal compounds
6
(
metal = Hg, Tl, Pb, Bi) with sodium nitrite in the presence of
1
trifluoroacetic acid. Then, subsequent oxidation to the nitro-
0
7 (a) G. K. S. Prakash, C. Panja, T. Mathew, V. Surampudi,
N. A. Petasis and G. A. Olah, Org. Lett., 2004, 6, 2205;
(b) S. Salzbrunn, J. Simon, G. K. S. Prakash, N. A. Petasis and
G. A. Olah, Synlett, 2000, 1485.
8 S. Saito and Y. Koizumi, Tetrahedron Lett., 2005, 46, 4715.
9 B. P. Fors and S. L. Buchwald, J. Am. Chem. Soc., 2009,
arene should take place easily at 801C in the presence of an
1
1
excess of the alkyl nitrite. With suitable conditions in our
hand, we tested the scope and limitations of this novel
methodology (Table 2).
1
31, 12898.
Methyl- and phenyl-substituted phenylboronic acids success-
fully gave the corresponding aromatic nitro compounds in
1
0 S. Uemura, A. Toshimitsu and M. Okano, J. Chem. Soc., Perkin
Trans. 1, 1978, 1076.
11 P. Zuman and B. Shah, Chem. Rev., 1994, 94, 1621.
56% and 68% yield, respectively (Table 2, entries 1 and 2).
This journal is c The Royal Society of Chemistry 2011
Chem. Commun., 2011, 47, 12462–12463 12463