2336
J. P. Schulte II, S. R. Tweedie
LETTER
(10) For examples of NaOPh in Pd-catalyzed couplings of
yield, enabled tolerance of sensitive functional groups
such as nitrile, nitro, and ester moieties, and allowed for
much shorter reaction times than previously reported. It
also has the added advantage of being easily removed
from the amine product by basic work-up techniques.
carbamates to aryl halides, see: (a) Hartwig, J. F.;
Kawatsura, M.; Hauck, S. I.; Shaughnessy, K. H.; Alcazar-
Roman, L. M. J. Org. Chem. 1999, 64, 5575. (b) For the
use of NaOPh in Suzuki couplings, see: Miyaura, N.;
Yamada, K.; Suginome, H.; Suzuki, A. J. Am. Chem. Soc.
1985, 107, 972. (c) For the use of NaOPh in isoprene
dimerization, see: Komatsu, A.; Akutagawa, S.; Someya, T.
U 3859374, 1975.
Acknowledgment
(11) For a study of the effects on reaction rate with the use of
sodium 2,4,6-tri-tert-butylphenoxide, NaOt-Bu, and
NaOCEt3, see: (a) Shekhar, S.; Hartwig, J. F.
We thank Dr. Matt Rainka for his helpful discussions and insights
into Pd chemistry.
Organometallics 2007, 26, 340. (b) Alcazar-Roman, L. M.;
Hartwig, J. F. J. Am. Chem. Soc. 2001, 123, 12905.
(12) All microwave reactions were conducted in a 2–5 mL
Biotage Microwave Vial Kit with sealable cap (code no.
351521) using a magnetic stirbar. Microwave heating was
performed with a single-mode cavity Emrys SmithCreator.
(13) General Procedure for Compounds Shown in Table 3
A 2–5 mL Biotage microwave vial was charged with the aryl
halide (1.10 mmol), sodium phenolate (191 mg, 1.65 mmol),
Pd2(dba)3 (12.6 mg, 0.0137 mmol, 2.5 mol% of Pd), and
Xantphos (19.1 mg, 0.0330 mmol, 3.0 mol%) followed by
degassed 1,4-dioxane (6.50 mL). The mixture was stirred
while degassing with argon for 1 min. The heteroaryl amine
(1.21 mmol) was added last, the vial was immediately
capped and sealed, then heated at 80 °C for 2 h. After cooling
to r.t., the mixture was diluted with EtOAc (400 mL),
washed with 1 N aq NaOH (3 × 100 mL) and brine (100
mL), dried over anhyd Na2SO4, filtered, and the solvent
removed under vacuum. The resulting residue was purified
over silica gel (12 g, hexanes–EtOAc) and the product was
freeze-dried from MeCN–H2O to provide the pure product.
(14) For studies on the scope and limitations of Pd-catalyzed
formation of biarylethers from sodium phenolates, see:
(a) Mann, G.; Incarvito, C.; Rheingold, A. L.; Hartwig, J. F.
J. Am. Chem. Soc. 1999, 121, 3224. (b) Kataoka, N.;
Shelby, Q.; Stambuli, J. P.; Hartwig, J. F. J. Org. Chem.
2002, 67, 5553. (c) Aranyos, A.; Old, D. W.; Kiyomori, A.;
Wolfe, J. P.; Sadighi, J. P.; Buchwald, S. L. J. Am. Chem.
Soc. 1999, 121, 4369.
References and Notes
(1) (a) Okushima, H.; Narimatsu, A.; Kobayashi, M.; Furuya,
R.; Kitada, Y. US 4 661 484, 1987. (b) Blancafort, P.;
Serradell, M. N.; Castañer, J.; Thorpe, P. Drugs Future
1983, 8, 223. (c) Kim, K. S.; Kimball, S. D.; Cai, Z.-W.;
Rawlins, D. B.; Misra, R. N.; Poss, M. A.; Webster, K. R.;
Hunt, J. T.; Han, W.-C. US 6 262 096B1, 2001. (d) Rackur,
G.; Hoffman, I. US 4 302 468, 1981. (e) Castañer, J.; Prous,
J. Drugs Future 1986, 11, 465.
(2) Yang, J.-S.; Lin, Y.-H.; Yang, C.-S. Org. Lett. 2002, 4, 777.
(3) Yin, J.; Zhao, M. M.; Huffman, M. A.; McNamara, J. M.
Org. Lett. 2002, 4, 3481.
(4) Usui, S.; Suzuki, T.; Hattori, Y.; Etoh, K.; Fujieda, H.;
Nishizuka, M.; Imagawa, M.; Nakagawa, H.; Kohda, K.;
Miyata, N. Bioorg. Med. Chem. Lett. 2005, 15, 1547.
(5) Byth, K. F.; Culshaw, J. D.; Green, S.; Oakes, S. E.; Thomas,
A. P. Bioorg. Med. Chem. Lett. 2004, 14, 2245.
(6) Tundel, R. E.; Anderson, K. W.; Buchwald, S. L. J. Org.
Chem. 2006, 71, 430.
(7) Anderson, K. W.; Tundel, R. E.; Ikawa, T.; Altman, R. A.;
Buchwald, S. L. Angew. Chem. 2006, 45, 6523.
(8) At the time of this manuscript’s preparation, a search via
ACD and ACX failed to find any commercially available
arylnonaflates.
(9) (a) Wolfe, J. P.; Buchwald, S. L. Tetrahedron Lett. 1997, 38,
6359. (b) Ali, M. H.; Buchwald, S. L. J. Org. Chem. 2001,
66, 2560. (c) Wolfe, J. P.; Buchwald, S. L. J. Org. Chem.
2000, 65, 1144. (d) Wolfe, J. P.; Tomori, H.; Sadighi, J. P.;
Yin, J.; Buchwald, S. L. J. Org. Chem. 2000, 65, 1158.
(e) Jensen, T. A.; Liang, X.; Tanner, D.; Skaerbaek, N.
J. Org. Chem. 2004, 69, 4936.
Synlett 2007, No. 15, 2331–2336 © Thieme Stuttgart · New York