Table 1 C–H borylation of arenes and heteroarenesa
In summary, aromatic C–H borylation of arenes and
heteroarenes with pinBH without an excess of substrate or
reagent provides a convenient, economical, and environmen-
tally benign route to regiodefined aryl- and heteroarylboronates.
Further investigations to survey the scope and limitation of this
C–H borylation, including that of monosubstituted arenes, other
heteroarenes, alkenes, and alkanes, as well as the application of
this catalyst system to other types of C–H functionalizations, are
in progress.
This work was partially supported by a Grant-in-Aid for
Scientific Research on Priority Areas (No. 14078101, “Reaction
Control of Dynamic Complexes”) from the Ministry of
Education, Culture, Sports, Science and Technology, Japan and
by the National Science Foundation (JFH). T.I. thanks the Itoh
Science Foundation and The Akiyama Foundation for support
of a part of his work.
Entry Product
Yield (%)b Entry Product
Yield (%)b
74% (2 h)
1
73% (8 h)
22% (24 h)
86% (8 h)
7
8
9
2
3
83% (1 h)
73% (24 h)
4
5
67% (8 h) 10
70% (24 h) 11
80% (8 h) 12
99% (0.5 h)
90% (1 h)
99% (2 h)
Notes and references
1
(a) M. Vaultier and B. Carboni, in Comprehensive Organometallic
Chemistry II, ed. E. W. Abel, F. G. A. Stone and G. Wilkinson,
Pergamon Press, Oxford, 1995, vol. 11, p. 191; (b) K. Ishihara and H.
Yamamoto, Eur. J. Org. Chem., 1999, 527; (c) S. Shinkai, M. Ikeda, A.
Sugasaki and M. Takeuchi, Acc. Chem. Res., 2001, 34, 494; (d) C. D.
Entwistle and T. B. Marder, Angew. Chem., Int. Ed., 2002, 41, 2927; (e)
A. H. Soloway, W. Tjarks, B. A. Barnum, F.-G. Rong, R. F. Barth, I. M.
Codogni and J. G. Wilson, Chem. Rev., 1998, 98, 1515; (f) W. Yang, X.
Gao and B. Wang, Med. Res. Rev., 2003, 23, 346.
6
2
3
A. N. Nesmeyanov and R. A. Sokolik, Methods of Elemento-Organic
Chemistry, North-Holland, Amsterdam, 1967, vol. 1.
(a) T. Ishiyama and N. Miyaura, J. Synth. Org. Chem., Jpn., 1999, 57,
503; (b) T. Ishiyama and N. Miyaura, J. Organomet. Chem., 2000, 611,
a
All reactions were carried out at 25 °C with pinacolborane (1.1 mmol),
(0.015 mmol), dtbpy
0.03 mmol), and hexane (6 mL). GC yields based on arenes or
heteroarenes. Reaction times are in parentheses.
arene or heteroarene (1.0 mmol), [Ir(OMe)(COD)]
(
2
b
3
92.
M. Murata, T. Oyama, S. Watanabe and Y. Masuda, J. Org. Chem.,
000, 65, 164.
4
5
6
2
A review, see: T. Ishiyama and N. Miyaura, J. Organomet. Chem., 2003,
680, 3.
C. N. Iverson and M. R. Smith, III, J. Am. Chem. Soc., 1999, 121,
bond cleavage.14 Electron-withdrawing substituents activated
the arene for the borylation process.
7
696.
The mechanism of the catalytic borylation of arenes and
7
8
H. Chen and J. F. Hartwig, Angew. Chem., Int. Ed., 1999, 38, 3391.
(a) H. Chen, S. Schlecht, T. C. Semple and J. F. Hartwig, Science, 2000,
287, 1995; (b) J.-Y. Cho, C. N. Iverson and M. R. Smith, III, J. Am.
Chem. Soc., 2000, 122, 12868; (c) M. K. Tse, J.-Y. Cho and M. R.
Smith, III, Org. Lett., 2001, 3, 2831.
heteroarenes with pinBH may proceed through an Ir(III)–Ir( )
V
cycle.1
by the reaction of an Ir(
addition of a C–H bond to the (pinB)
an (Ar)(H)(pinB) Ir( ) species, and reductive elimination of
pinB–Ar from the (Ar)(H)(pinB) Ir( ) species to give a
H)(pinB) Ir(III) complex would be followed by oxidative
addition of pinBH and reductive elimination of H to regenerate
the (pinB) Ir(III) intermediate.
0–12,15
Generation of a (pinB)
) complex with pinBH, oxidative
Ir(III) intermediate to yield
Ir(III) intermediate
10,11a,16
3
I
3
3
V
9 S. Shimada, A. S. Batsanov, J. A. K. Howard and T. B. Marder, Angew.
Chem., Int. Ed., 2001, 40, 2168.
3
V
1
1
0 J.-Y. Cho, M. K. Tse, D. Holmes, R. E. Maleczka, Jr. and M. R. Smith,
III, Science, 2002, 295, 305.
1 (a) T. Ishiyama, J. Takagi, K. Ishida, N. Miyaura, N. R. Anastasi and J.
F. Hartwig, J. Am. Chem. Soc., 2002, 124, 390; (b) J. Takagi, K. Sato,
J. F. Hartwig, T. Ishiyama and N. Miyaura, Tetrahedron Lett., 2002, 43,
5649.
(
2
2
3
The direct preparation of aryl- and heteroarylboronates from
pinBH and the corresponding arenes or heteroarenes creates an
efficient, one-pot, two-step procedure for the synthesis of
unsymmetrical biaryls. The biaryl shown in Scheme 2 was
produced in 91% yield by sequential generation of 5-boryl-
12 (a) T. Ishiyama, J. Takagi, J. F. Hartwig and N. Miyaura, Angew. Chem.,
Int. Ed., 2002, 41, 3056; (b) T. Ishimaya, J. Takagi, Y. Yonekawa, J. F.
Hartwig and N. Miyaura, Adv. Synth. Catal., 2003, 345, 1103.
1
3 (a) L. Dong, S. B. Duckett, K. F. Ohman and W. D. Jones, J. Am. Chem.
Soc., 1992, 114, 151; (b) T. Morikita, M. Hirano, A. Sasaki and S.
Komiya, Inorg. Chim. Acta, 1999, 291, 341; (c) S. N. Ringelberg, A.
Meetsma, B. Hessen and J. H. Teuben, J. Am Chem. Soc., 1999, 121,
1
,3-dichlorobenzene from pinBH (1.43 mmol) and 1,3-di-
chlorobenzene (1.3 mmol) in hexane (2 mL), followed by
reaction of the resulting arylboronate with added methyl
4
(
2 3 4
-bromobenzoate (1.0 mmol), PdCl (dppf) (0.03 mmol), K PO
6
082.
3.0 mmol), and DMF (4 mL) at 60 °C.17
1
4 J. D. Atwood, in Comprehensive Organometallic Chemistry II, ed. E.
W. Abel, F. G. A. Stone and G. Wilkinson, Pergamon Press, Oxford,
1
995, vol. 8, p. 303.
1
5 For theoretical studies, see: H. Yamazaki, H. Tamura, M. Sugimoto, H.
Sato and S. Sakaki, 49th Symposium on Organometallic Chemistry,
Kinki Chemical Society, Osaka, Japan, 2002, PA119.
1
1
6 P. Nguyen, H. P. Blom, S. A. Westcott, N. J. Taylor and T. B. Marder,
J. Am. Chem. Soc., 1993, 115, 9329.
7 (a) N. Miyaura and A. Suzuki, Chem. Rev., 1995, 95, 2457; (b) N.
Miyaura, Top. Curr. Chem., 2002, 219, 11; (c) A. Suzuki and H. C.
Brown, Organic Syntheses Via Boranes, Aldrich Chemical Company,
Inc., Milwaukee, 2003, vol. 3.
Scheme 2
CHEM. COMMUN., 2003, 2924–2925
2925