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Synlett 2017; 28(06): 724-728
DOI: 10.1055/s-0036-1588112
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© Georg Thieme Verlag Stuttgart · New York

Mn(OAc)3-Mediated Synthesis of 3-Phosphonyldihydrofurans from β-Ketophosphonates and Alkenes

Guozhang Lu
Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, P. R. of China   Email: t12g21@xmu.edu.cn
,
Binzhou Lin
Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, P. R. of China   Email: t12g21@xmu.edu.cn
,
Yuzhen Gao
Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, P. R. of China   Email: t12g21@xmu.edu.cn
,
Jianxi Ying
Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, P. R. of China   Email: t12g21@xmu.edu.cn
,
Guo Tang*
Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, P. R. of China   Email: t12g21@xmu.edu.cn
,
Yufen Zhao
Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, P. R. of China   Email: t12g21@xmu.edu.cn
› Author Affiliations
Further Information

Publication History

Received: 24 September 2016

Accepted after revision: 13 November 2016

Publication Date:
01 December 2016 (online)

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Abstract

A new, general method for the synthesis of 3-phosphonyldihydrofuran derivatives has been achieved through Mn(OAc)3-mediated radical cyclization between β-ketophosphonates and alkenes. This transformation allows the direct formation of C–C/C–O bonds and the construction of a dihydrofuran ring in one reaction with operational simplicity and excellent functional-group compatibility.

Key words

manganese - phosphonyldihydrofurans - β-ketophosphonates - alkenes - radicals

Supporting Information

    Supporting information for this article is available online at http://dx.doi.org/10.1055/s-0036-1588112.
  • Supporting Information
 

  • References and Notes

  • 16 Experimental Procedure for the Synthesis of 1a Styrene (2.08 g, 20 mmol) was added to a mixture of H-diethyl phosphonate (5.52 g, 40 mmol), CuBr2 (111.5 mg, 0.5 mmol, 2.5 mol%), FeBr3 (162 mg, 1 mmol, 5.0 mol%), and Et3N (2.02g, 20 mmol) in DMSO (40 mL) at r.t. under O2 (balloon). The reaction mixture was stirred at 55 °C for 48 h. After completion of the reaction, water (20 mL) was added to the reaction mixture, and the resulting mixture was extracted with CH2Cl2. The organic layer was washed with 0.1 mol/L HCl (1 × 20 mL), water (3 × 20 mL), brine (1 × 20 mL), and the separated aqueous phase was extracted with CH2Cl2 (2 × 20 mL). The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by flash chromatography on silica gel using a PE–EtOAc mixture (3:1, v/v) as the eluent to afford 1a as a light yellow oil (3.07 g, 60%). 1H NMR (400 MHz, CDCl3): δ = 8.01 (d, J = 8.0 Hz, 2 H), 7.59 (t, J = 7.5 Hz, 1 H), 7.47 (t, J = 8.5 Hz, 2 H), 4.17–4.09 (m, 4 H), 3.65 (d, J = 22.6 Hz, 2 H), 1.27 (t, J = 6.9 Hz, 6 H). 13C{1H} NMR (100 MHz, CDCl3): δ = 191.9 (d, J = 6.6 Hz), 136.5, 133.7, 129.0, 128.6, 62.7 (d, J = 6.5 Hz), 38.4 (d, J = 130.1 Hz), 16.2 (d, J = 6.1 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ = 20.0. Other β-ketophosphonates were prepared similarly. Experimental Procedure for the Synthesis of 2q A 15 mL Schlenk tube charged with α-bromostyrene (0.377 g, 268 μL, 2.0 mmol), (4-methoxyphenyl) boronic acid (2.6 mmol, 1.3 equiv), K3PO4 (1.27 g, 6.0 mmol, 3.0 equiv), Pd(PPh3)4 (0.116 g, 5 mol%), and THF (10 mL) was heated at 80 °C for 12 h. After completion, the reaction mixture was evaporated, and the product was purified by flash silica gel column chromatography using PE as the eluent to afford 2q as a white solid (307 mg, 73%). 1H NMR (400 MHz, CDCl3): δ = 7.32–7.26 (m, 7 H), 6.85 (d, J = 8.8 Hz, 2 H), 5.37 (d, J = 17.0 Hz, 2 H), 3.81 (s, 3 H). 13C{1H} NMR (100 MHz, CDCl3): δ = 159.6, 149.7, 142.0, 134.2, 129.6, 128.5, 128.3, 127.8, 113.7, 113.1, 55.5. Other alkenes were prepared similarly. Experimental Procedure for the Synthesis of 3-Phosphodihydrofuran Derivatives A 15 mL Schlenk tube containing Mn(OAc)3·H2O (0.60 mmol, 3.0 equiv) was evacuated and purged with argon three times. β-Ketophosphonates (1, 0.40 mmol, 2.0 equiv), alkenes (2, 0.20 mmol, 1.0 equiv), and AcOH (2.0 mL) were sequentially added to the system at r.t. The reaction mixture was heated with stirring at 80 °C for 6 h. Upon completion, the reaction solution was concentrated in vacuo, then added 15 mL sat. NaHCO3 solution, and extracted with EtOAc (3 × 10 mL). The organic layer was dried over Na2SO4, and concentrated under vacuum. The residue was purified by silica gel column chromatography using a PE–EtOAc mixture (from 3:1 to 1:1, v/v) as the eluent to afford the corresponding products. Diethyl (2,5,5-Triphenyl-4,5-dihydrofuran-3-yl)phosphonate (3a; New Compound) Yield 75% (65 mg); light yellow liquid. 1H NMR (400 MHz, CDCl3): δ = 7.95–7.93 (m, 2 H), 7.46 (d, J = 8.0 Hz, 4 H), 7.42–7.39 (m, 2 H), 7.33 (t, J = 7.6 Hz, 4 H), 7.28–7.24 (m, 2 H), 3.97–3.84 (m, 4 H), 3.78 (d, J = 3.2 Hz, 2 H), 1.12 (t, J = 7.0 Hz, 6 H). 13C{1H} NMR (100 MHz, CDCl3): δ = 163.8 (d, J = 25.8 Hz), 145.0, 130.4, 129.7, 129.0, 128.4, 127.7, 127.6, 125.7, 94.6 (d, J = 213.6 Hz), 91.5 (d, J = 11.6 Hz), 61.77 (d, J = 5.2 Hz), 47.8 (d, J = 9.4Hz), 16.26 (d, J = 6.7 Hz). 31P{1H} (162 MHz, CDCl3): δ = 16.5. HRMS: m/z calcd for C26H28O4P [M + H]+: 435.1720; found: 435.1719.