6348
J. Wang et al. / Tetrahedron Letters 52 (2011) 6346–6348
5. Preparation of methyl 3,4-dibromo-2-thiophenecarboxylate:
Supplementary data
O
O
S
S
Zn, HOAc
70 C, 90%
nBuLi (1.1 equiv),
Br
S
Br
Br
OMe
OH
OMe
Supplementary data associated (experimental procedures and
characterization data for 1, 2, 3, 4, 1a, 1b, 2a, 2b, 3a, 3b, 5a, 4b,
7a, 7b, 8a, and 8b are available upon requests) with this article
CO, THF, -78 o
90%
C
°
Br
Br
Br
Br
Br
Br
6. Preparation of alcohol 1 and 3:
O
O
S
S
S
Tf2O, Pyridine
DCM, 92%
Dibal-H (5 equiv.)
OMe
OMe
DCM, -20 °C, 83%
Br
Br
Br
OH
OTf
OTf
References and notes
1
3
7. Preparation of bis-esters 2 and 4:
1. (a) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457; (b) Suzuki, A. J.
Organomet. Chem. 1999, 576, 147; Miyaura, N. In Advances in Metal-Organic
Chemistry; Liebeskind, L. S., Ed.; JAI: London, 1998; Vol. 6, p 187.
2. (a) Echavarren, A. M.; Stille, J. K. J. Am. Chem. Soc. 1987, 109, 5478; (b) Jutand,
A.; Mosleh, A. Organometallics 1995, 14, 1810; (c) Kamikawa, T.; Hayashi, T.
Tetrahedron Lett. 1997, 38, 7087; (d) Espino, G.; Kurbangalieva, A.; Brown, J. M.
Chem. Commun. 2007, 1742.
3. (a) Ohe, T.; Miyaura, N.; Suzuki, A. Synlett 1990, 221; (b) Ohe, T.; Miyaura, N.;
Suzuki, A. J. Org. Chem. 1993, 58, 2201; (c) Pinto, D. J.; Batt, D. G.; Pitts, W. J.;
Petraitis, J. J.; Orwat, M. J.; Wang, S.; Jetter, J. W.; Sherk, S. R.; Houghton, G. C.;
Copeland, R. A.; Covington, M. B.; Trzaskos, J. M.; Magolda, R. L. Bioorg. Med.
Chem. Lett. 1999, 9, 919; (d) Littke, A. F.; Dai, C.; Fu, G. C. J. Am. Chem. Soc. 2000,
122, 4020; (e) Fu, J.; Snieckus, V. Tetrahedron Lett. 1990, 31, 1665.
4. (a) Haugwitz, R. D.; Angel, R. G.; Jacobs, G. A.; Maurer, B. V.; Narayanan, V. L. J.
Med. Chem. 1982, 25, 969; (b) Schroter, S.; Stock, C.; Bach, T. Tetrahedron 2005,
61, 2245; (c) Lin, X.; Murray, J. M.; Rico, A. C.; Wang, M. X.; Chu, D. T.; Zhou, Y.;
Rosario, M. D.; Kaufman, S.; Ma, S.; Fang, E.; Crawford, K.; Jefferson, A. B. Bioorg.
Med. Chem. Lett. 2006, 16, 4163; (d) Wan, Z.; Follows, B.; Kirincich, S.; Wilson,
D.; Binnun, E.; Xu, W.; Joseph-McCarthy, D.; Wu, J.; Smith, M.; Tam, M.; Erbe,
D.; Tam, S.; Saiah, E.; Jinbo Lee, J. Bioorg. Med. Chem. Lett. 2007, 17, 2913; (e)
Seefeld, M.A.; Hamajima, T.; Jung, D.K.; Hiroko, P.R.; Reno, M.J.; Rouse, M.B.;
Heerding, D.A.; Tang, J.; Wang, J.; U.S. Patent WO 2007076423 A2, 2007.
O
O
O
1. nBuLi (2.1 equiv.), -78 °C
Tf2O, Pyridine
DCM, 92%
S
S
Br
OMe
MeO
2. Methyl chlorofomate (2.2 equiv.),
OMe
OH
Br
Br
OH
-78
°
C, THF, 75%
2
HO
S
OH
Dibal-H (5 equiv.)
DCM, -20 C, 83%
°
Br
OTf
4
8. Smith, G. B.; Dezeny, G. C.; Hughes, D. L.; King, A. O.; Verhoeven, T. R. J. Org.
Chem. 1994, 59, 8151.
9. Favarque, J. F.; Pfluger, F.; Troupel, M. J. Organomet. Chem. 1981, 208, 2276.
10. Guram, A. S.; Wang, X.; Bunel, E. E.; Faul, M. M.; Larsen, R. D.; Martinelli, M. J. J.
Org. Chem. 2007, 72, 5104; Notes. General procedure for Suzuki cross-coupling
reactions: To a solution of 3,4/4,3-bromotriflate thiophene (0.5 mmol, 1.0
equiv) in dioxane or DME/H2 O (5 mL/1 mL) were added K2 CO3 (1.5 mmol, 3.0
equiv), Pd(0) (5 mol %), and boronic acid/ester (0.525 mmol,1.05 equiv). The
reaction mixture was heated to 70 C in a sealed tube. The reaction process was
monitored by LC–MS. After the reaction was done, the reaction mixture was
concentrated under vacuum and purified by silica gel chromatography.