Download PDF
Synlett 2011(10): 1472-1476  
DOI: 10.1055/s-0030-1260763
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Palladium-Catalyzed Direct Arylation Reaction of 2,3,5-Trisubstituted Furans with Aryl Iodides or Aryl Bromides

Hua Cao*, Dongsheng Shen, Haiying Zhan, Liuqing Yang
School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Guangzhou 510006, P. R. of China
Fax: +86(760)88207939; e-Mail: hua.cao@mail.scut.edu.cn;
Further Information

Publication History

Received 26 February 2011
Publication Date:
26 May 2011 (online)

   Permissions and Reprints All articles of this category
Preview

Abstract

Pd-catalyzed direct arylation of 2,3,5-trisubstituted furans with a variety of aryl iodides or aryl bromides that showed high activity with reasonably broad scope was developed. Under optimal conditions, all reactions gave the desired products in moderate to good yields.

Key words

palladium - arylation reaction - 2,3,5-trisubstituted furans - aryl iodides - aryl bromides

14

General Procedure for the Synthesis of 1a
Diethyl acetylenedicarboxylate (2 mmol), prop-2-yn-1-ol (2 mmol), DABCO (0.2 mmol) in CH2Cl2 were stirred for 10 min at r.t. And then the solution was evaporated to dryness under reduced pressure. Subsequently, CuI (10% mmol) and DMF were added at 80 ˚C. After completion of the reaction (monitored by TLC), the solution was evaporated to dryness under reduced pressure, and then H2O (10 mL) was added. The aqueous solution was extracted with Et2O (3 × 10 mL), and the combined extract was dried with anhyd MgSO4. The solvent was removed, and the crude product was separated by column chromatography to give a pure sample of 1a.

15

General Procedure for the Synthesis of 1c
Diethyl acetylenedicarboxylate (2 mmol), prop-2-yn-1-ol (2 mmol), DABCO (0.2 mmol) in CH2Cl2 were stirred for 10 min at r.t. And then the solution was evaporated to dryness under reduced pressure. Subsequently, AgOAc/Ph3P and toluene were added at 50 ˚C. After completion of the reaction (monitored by TLC), the solution was evaporated
to dryness under reduced pressure, and then H2O (10 mL) was added. The aqueous solution was extracted with Et2O (3 × 10 mL), and the combined extract was dried with anhyd MgSO4. The solvent was removed, and the crude product was separated by column chromatography to give a pure sample of 1c.

16

General Procedure for the Synthesis of 3a
To the mixture of Pd(OAc)2 (5% mol), Ph3P (10% mol), Cs2CO3 (1.0 mmol), 1a (0.5 mmol), 2a (0.7 mmol), and DMP (4 mL) were added successively. The mixture was stirred at 120 ˚C for 20 hours. The solution was extracted with EtOAc (3 × 15 mL), and the combined extract was dried with anhyd MgSO4. Solvent was removed, and the residue was separated by column chromatography to give the pure sample 3a.
Diethyl 5-Formyl-4-phenylfuran-2,3-dicarboxylate (3a)
¹H NMR (400 MHz, CDCl3): δ = 9.70 (s, 1 H), 7.47 (s, 5 H), 4.43 (q, J = 8.0 Hz, 2 H), 4.28 (q, J = 8.0 Hz, 2 H), 1.40 (t, J = 8.0 Hz, 3 H), 1.22 (q, J = 8.0 Hz, 3 H). ¹³C NMR (100 MHz, CDCl3): δ = 178.0, 162.0, 157.1, 147.5, 144.3, 136.1, 129.7, 129.5, 128.7, 127.5, 126.3, 62.3, 62.1, 14.0, 13.7.
MS (EI): m/z (%) = 316, 288, 225, 213, 170, 115, 77.