Angewandte
Chemie
beater, Chem. Commun. 2005, 2881.
Synlett 2005, 4, 619; c) M. S. Mohamed Ahmed, A. Mori,
Tetrahedron 2004, 60, 9977; d) C. Wolf, R. Lerebours, Org.
Biomol. Chem. 2004, 2, 2161; e) S. Bhattacharya, S. Sengupta,
Tetrahedron Lett. 2004, 45, 8733.
[5] For a NiCl2/dppe/trisulfonated triphenylphosphine system, see:
J.-C. Galland, M. Savignac, J. P. Genet, Tetrahedron Lett. 1999,
40, 2323.
[22] Choice of the palladium source and ligands 2 and 4 was made on
the basis of our previous reports. See references [3] and [20].
[23] a) Use of electron-deficient zinc acetylides allows coupling with
aryl halides; see: E.-I. Negishi, L. Anastasia, Chem. Rev. 2003,
103, 1979, and references therein. b) Use of K2CO3 allows the
coupling of electron-deficient terminal alkynes and electron-
deficient or neutral aryl iodides; see: T. Eckert, J. Ipaktschi,
Synth. Commun. 1998, 28, 327. c) Use of K2CO3 allows the
coupling of electron-deficient terminal alkynes and diphenylio-
donium salts; see: U. Radhakrishnan, P. J. Stang, Org. Lett. 2001,
3, 859. d) Water was essential to the coupling reaction of aryl
iodides and various alkynoates; see: Y. Uozumi, Y. Kobayashi,
Heterocycles 2003, 59, 71.
[6] For oxime-derived palladacycles, see: a) L. Botella, C. Najera,
Angew. Chem. 2002, 114, 187; Angew. Chem. Int. Ed. 2002, 41,
179; b) L. Botella, C. Najera, J. Organomet. Chem. 2002, 663, 46.
[7] For di-2-pyridylmethylamine-based palladium complexes, see:
C. Najera, J. Gil-Molto, S. Karlstrom, L. R. Falvello, Org. Lett.
2003, 5, 1451.
[8] For palladium N-heterocyclic carbene complexes, see: a) I.
Ozdemir, Y. Gok, N. Gurbuz, E. Cetinkaya, B. Cetinkaya,
Heteroat. Chem. 2004, 15, 419; b) I. Özdemir, S. Demir, S. Yaser,
B. Cetinkaya, Appl. Organomet. Chem. 2005, 19, 55.
[9] For TBAB–water mixtures, see: R. B. Bedford, M. E. Blake,
C. P. Butts, D. Holder, Chem. Commun. 2003, 466.
[10] a) H. Gulyas, A. Szollosy, P. Szabo, P. Halmos, J. Bakos, Eur. J.
Org. Chem. 2003, 2775; b) W. P. Mul, K. Ramkisoensing, P. C. J.
Kamer, J. N. H. Reek, A. J. van der Linder, A. Marson,
P. W. N. M. van Leeuwen, Adv. Synth. Catal. 2002, 344, 293;
c) H. Gulyas, A. Szollosy, B. E. Hanson, J. Bakos, Tetrahedron
Lett. 2002, 43, 2543; d) E. Schwab, S. Mecking, Organometallics
2001, 20, 5504.
[11] a) L. R. Moore, K. H. Shaughnessy, Org. Lett. 2004, 6, 2 2 5;
b) E. C. Western, J. R. Daft, E. M. Johnson II, P. M. Gannett,
K. H. Shaughnessy, J. Org. Chem. 2003, 68, 6767; c) A. E.
Sollewijn Gelpke, J. J. N. Veerman, M. S. Goedheijt, P. C. J.
Kamer, P. W. N. M. van Leeuwen, H. Hiemstra, Tetrahedron
1999, 55, 6657; d) H. Bahrmann, K. Bergrath, H.-J. Kleiner, P.
Lappe, C. Naumann, D. Peters, D. Regnat, J. Organomet. Chem.
1996, 520, 97; e) J. P. Genet, A. Linquist, E. Blart, V. Mouries, M.
Savignac, Tetrahedron Lett. 1995, 36, 1443.
[12] a) R. B. DeVasher, L. R. Moore, K. H. Shaughnessy, J. Org.
Chem. 2004, 69, 7919; b) R. B. DeVasher, J. M. Spruell, D. A.
Dixon, G. A. Broker, S. T. Griffin, R. D. Rogers, K. H. Shaugh-
nessy, Organometallics 2005, 24, 962.
[13] A. Konovets, A. Penciu, E. Framery, N. Percina, C. Goux-Henry,
D. Sinou, Tetrahedron Lett. 2005, 46, 3205.
[14] R. K. Arvela, N. E. Leadbeater, Org. Lett. 2005, 7, 2101.
[15] For an excellent review on catalyst systems used in Suzuki–
Miyaura couplings conducted in aqueous media and using
microwave irradiation, see references [4d] and [4e], and refer-
ences therein.
[16] Our attempts to effect the coupling of 2-bromomesitylene with
2,6-dimethylphenylboronic acid in water at 1008C to form a
biaryl with four substituents ortho to the aryl–aryl connection
provided none of the desired product. This is in contrast to what
is observed with a catalytic system using 1. See ref. [2c].
[17] The sulfonic acid is undoubtedly rapidly transformed to the
sulfonate under the reaction conditions. For examples of Suzuki–
Miyaura couplings of aryl halides with protected sulfonic acids,
see: a) B. G. Avitabile, C. A. Smith, D. B. Judd, Org. Lett. 2005,
7, 843; b) A. Hari, B. L. Miller, Org. Lett. 1999, 1, 2 109; c) E. W.
Baxter, J. K. Rueter, S. O. Nortey, A. B. Reitz, Tetrahedron Lett.
1998, 39, 979.
[18] See references [4] and [10b].
[19] The authors report that monodentate phosphines are poor
ligands for the Suzuki–Miyaura coupling of 2-amino-pyridines
and pyrimidines. This result suggests that use of a highly active
catalyst system such as Pd/2 at least in some instances overcomes
this limitation; see: T. Itoh, T. Mase, Tetrahedron Lett. 2005, 46,
3573.
[20] D. Gelman, S. L. Buchwald, Angew. Chem. 2003, 115, 6175;
Angew. Chem. Int. Ed. 2003, 42, 5993.
[21] For recent reports of Sonogashira coupling reactions conducted
in water or water/organic biphasic solvents, see: a) B. Liang, M.
Dai, J. Chen, Z. Yang, J. Org. Chem. 2005, 70, 391; b) G. Zhang,
Angew. Chem. Int. Ed. 2005, 44, 6173 –6177
ꢀ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
6177