Synlett 2016; 27(05): 794-798
DOI: 10.1055/s-0035-1560554
letter
© Georg Thieme Verlag Stuttgart · New York

Palladium-Catalyzed Dehydrogenation Coupling–Cyclization Reactions of Acetylenic Acids with Iodonium Ylides for the Synthesis of 2(5H)-Furanones

Wen-Guang Li
Institute of Applied Chemistry Central South University of Forestry and Technology, Changsha, Hunan 410004, P. R. of China   Email: psfhunan@163.com
,
Bo Cai
Institute of Applied Chemistry Central South University of Forestry and Technology, Changsha, Hunan 410004, P. R. of China   Email: psfhunan@163.com
,
Hong-Bo Xiao
Institute of Applied Chemistry Central South University of Forestry and Technology, Changsha, Hunan 410004, P. R. of China   Email: psfhunan@163.com
,
Shao-Feng Pi*
Institute of Applied Chemistry Central South University of Forestry and Technology, Changsha, Hunan 410004, P. R. of China   Email: psfhunan@163.com
,
Han-Zhou Sun
Institute of Applied Chemistry Central South University of Forestry and Technology, Changsha, Hunan 410004, P. R. of China   Email: psfhunan@163.com
› Author Affiliations
Further Information

Publication History

Received: 08 September 2015

Accepted after revision: 15 November 2015

Publication Date:
14 December 2015 (online)


Abstract

A new route for the synthesis of 2(5H)-furanones is presented via Pd(PPh3)4-catalyzed cascade reaction of acetlenic acids with iodonium ylides using K2CO3 as the base. The cascade proceeds through dehydrogenation coupling and cyclization under mild conditions.

Supporting Information

 
  • References and Notes

  • 9 Gao Q, Zheng B.-F, Li J.-H, Yang D. Org. Lett. 2005; 7: 2185
  • 10 Gou F.-R, Bi H.-P, Guo L.-N, Guan Z.-H, Liu X.-Y, Liang Y.-M. J. Org. Chem. 2008; 73: 3837
  • 11 Typical Experimental Procedure for the Palladium-Catalyzed Dehydrogenation Coupling–Cyclization Reactions of Acetylenic Acids with Iodonium Ylides To a Schlenk tube were added 3-phenylpropiolic acid (1a, 29.2 mg, 0.2 mmol), dimethyl 2-(phenyl-λ3-iodanylidene)malonate (2a, 80.2 mg, 0.24 mmol), Pd(PPh3)4 (13.8 mg, 0.06 mmol), K2CO3 (60.8 mg, 0.4 mmol), and CH2Cl2 (2 mL). Then the tube was charged with argon and was stirred at r.t. for the indicated time until complete consumption of starting material as monitored by TLC and GC–MS analysis. After the reaction was finished, the reaction diluted in Et2O and concentrated in vacuum, and the resulting residue was purified by silica gel column chromatography (hexane–EtOAc) to afford the desired product 3aa (54.1 mg, 98%). Dimethyl 5-Oxo-3-phenylfuran-2,2(5H)-dicarboxylate (3aa) Yield: 54.1 mg (98%); white solid; mp 104–106 °C. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.56 (d, J = 8.0 Hz, 2 H), 7.42–7.37 (m, 3 H), 6.46 (s, 1 H), 3.76 (s, 6 H). 13C NMR (100 MHz, CDCl3, 25 °C): δ = 170.13, 164.61, 162.24, 131.86, 128.86, 128.54, 116.20, 99.99, 88.06, 54.05. IR (neat): 2958, 2852, 1779, 1749, 1262, 797cm–1. LRMS (EI, 70 eV): m/z (%) = 276 (5) [M], 232 (9), 188 (77), 161 (100), 115 (32), 102 (60). ESI-HRMS: m/z calcd for C10H13O6 [M + H]+: 227.0712; found: 277.0708. Dimethyl 3-(4-Methoxyphenyl)-5-oxofuran-2,2(5H)-dicarboxylate (3ba) Yield: 53.8 mg (88%); colorless oil. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.56 (d, J = 8.0 Hz, 2 H), 6.88 (d, J = 8.0 Hz, 2 H), 6.33 (s, 1 H), 3.86 (s, 6 H), 3.84 (s, 3 H). 13C NMR (100 MHz, CDCl3, 25 °C): δ = 164.89, 162.80, 130.98, 120.91, 114.28, 113.19, 60.42, 55.50, 54.00, 53.87. IR (neat): 2924, 2855, 1761, 1376, 1265, 743 cm–1. LRMS (EI, 70 eV): m/z (%): 307 (1) [M], 247 (10), 219 (27), 189 (3), 175 (3), 132 (37), 117 (15), 59 (100). ESI-HRMS: m/z calcd for C10H13O6 [M + H]+: 307.0818; found: 307.0812. Dimethyl 3-Ethyl-5-oxofuran-2,2(5H)-dicarboxylate (3ca) Yield: 33.8 mg (74%); colorless oil. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.92 (s, 1 H), 3.82 (d, J = 12.0 Hz, 6 H), 2.56–2.50 (m, 2 H), 1.19 (d, J = 8.0 Hz, 3 H). 13C NMR (100 MHz, CDCl3, 25 °C): δ = 170.36, 169.22, 164.31, 117.00, 88.7, 60.41, 53.90, 21.59, 11.20. IR (neat): 2954, 2924, 2854, 2361, 1784, 1755, 1458, 742, 684 cm–1. LRMS (EI, 70 eV): m/z (%) = 226 (9) [M], 184 (20) [M], 168 (16), 141 (100), 126 (17). ESI-HRMS: m/z calcd for C10H13O6 [M + H]+: 229.0712; found: 229.0707. Ethyl 5-Oxo-3-phenyl-2,5-dihydrofuran-2-carboxylate (3ab) Yield: 37.2 mg (80%); white solid; mp 93–95 °C. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.54 (t, J = 4.0 Hz, 2 H), 7.42–7.39 (m, 3 H), 6.37 (s, 1 H), 5.81 (s, 1 H), 4.11 (m, 2 H), 1.11 (m, 6 H). 13CNMR (100 MHz, CDCl3, 25 °C): δ = 172.18, 166.16, 162.43, 132.02, 129.18, 128.71, 127.49, 114.50, 80.06, 62.71, 13.83. IR (neat): 3108, 2919, 2850, 1763, 1465, 1155, 763 cm–1. LRMS (EI, 70 eV): m/z (%) = 233 (3) [M], 203 (25), 146 (100), 131 (29). ESI-HRMS: m/z calcd for C13H13O4 [M + H]+: 233.0814; found: 233.0808. Methyl 5-Oxo-3-phenyl-2,5-dihydrofuran-2-carboxylate (3ac) Yield: 36.2 mg (83%); white solid; mp 75–76 °C. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.54 (t, J = 4.0 Hz, 2 H), 7.44–7.40 (m, 3 H), 6.38 (s, 1 H), 5.85 (s, 1 H), 3.65 (s, 3 H). 13C NMR (100 MHz, CDCl3, 25 °C): δ = 172.15, 166.71, 162.32, 132.09, 129.29, 128.85, 128.82, 128.60, 171.44, 114.45, 53.38. IR (neat): 2957, 1766, 1621, 1437, 1158, 788, 688 cm–1. LRMS (EI, 70 eV): m/z (%) = 218 (10) [M], 159 (100), 146 (20), 77 (56). ESI-HRMS: m/z calcd for C12H10O4 [M + H]+: 219.0657; found: 219.0650. Ethyl 2-Benzoyl-5-oxo-3-phenyl-2,5-dihydrofuran-2-carboxylate (3ad) Yield: 64.5 mg (96%); light yellow solid; mp 48–50 °C. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.96 (d, J = 8.0 Hz, 2 H), 7.60 (d, J = 8.0 Hz, 3 H), 7.43–7.36 (m, 5 H), 6.50 (s, 1 H), 4.16–4.10 (m, 2 H), 1.02 (t, J = 6.0 Hz, 3 H). 13C NMR (75 MHz, CDCl3, 25 °C): δ = 189.13, 170.15, 165.88, 164.38, 134.15, 134.02, 131.64, 129.63, 129.29, 129.23, 128.73, 128.67, 116.49, 63.49, 13.67. IR (neat): 2925, 2854, 1767, 1712, 1450, 1262, 1028, 712 cm–1. LRMS (EI, 70 eV): m/z (%) = 337 (1) [M], 207 (1), 105 (100), 103 (2), 77 (28). ESI-HRMS: m/z calcd for C20H17O5 [M + H]+: 337.1076; found: 337.1071. Vinyl 2-Acetyl-5-oxo-3-phenyl-2,5-dihydrofuran-2-carboxylate (3ae) Yield: 44.6 mg (82%); pale yellow oil. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.47–7.45 (m, 2 H), 7.42–7.37 (m, 3 H), 6.49 (s, 1 H), 5.42–5.35 (m, 1 H), 5.00–4.90 (m, 2 H), 2.12 (s, 3 H). 13C NMR (75 MHz, CDCl3, 25 °C): δ = 203.09, 117.82, 164.87, 131.71, 129.35, 129.06, 127.64, 121.02, 116.56, 93.90, 37.11, 29.71, 24.06. IR (neat): 2923, 2852, 1766, 1188, 769 cm–1. LRMS (EI, 70 eV): m/z (%) = 272 (6) [M], 245 (14), 201 (37), 158 (100), 77 (30). ESI-HRMS: m/z calcd for C15H13O5 [M + H]+: 273.0763; found: 273.0758. Methyl 5-Oxo-3-phenyl-2-propionyl-2,5-dihydrofuran-2-carboxylate (3af) Yield: 48.2 mg (88%); white solid; mp 101–103. 1H NMR (400 MHz,CDCl3, 25 °C): δ = 7.61–7.59 (d, J = 8.0 Hz, 2 H), 7.49–7.27 (m, 3 H), 6.54 (s, 1 H), 3.83 (s, 3 H), 2.87–2.77 (m, 1 H), 2.65–2.55 (m, 1 H), 1.09–1.05 (t, J = 8.0 Hz, 3 H). 13C NMR (75 MHz, CDCl3, 25 °C): δ = 201.0, 170.4, 165.4, 162.8, 131.9, 120.3, 128.8, 128.8, 128.7, 127.4, 115.7, 92.5, 92.5, 79.0 , 77.4, 53.9, 31.4. IR (neat): 2957, 2851, 2359, 1776, 1255, 739 cm–1. LRMS (EI, 70 eV): m/z (%) = 274 (6) [M], 259 (14), 200 (37), 146 (100), 77 (30). ESI-HRMS: m/z calcd for C15H14O5 [M + H]+: 274.0841; found: 275.0837. Methyl 2-Butyryl-5-oxo-3-phenyl-2,5-dihydrofuran-2-carboxylate (3ag) Yield: 44.9 mg (78%); white solid; mp 113–117. 1H NMR (400 MHz,CDCl3, 25 °C): δ = 7.61–7.59 (d, J = 8.0 Hz, 2 H), 7.49–7.41 (m, 3 H), 6.54 (s, 1 H), 3.83 (s, 3 H), 2.77–2.71 (m, 1 H), 2.58–2.40 (m, 1 H), 1.66–1.55 (m, 2 H), 0.89–0.86 (t, J = 4.0 Hz, 3 H). 13C NMR (75 MHz, CDCl3, 25 °C): δ = 198.0, 170.4, 165.6, 164.2, 162.8, 162.6, 131.8, 129.1, 128.9, 128.7, 127.5, 115.9, 114.5, 92.7, 80.2, 71.8, 26.0, 21.5, 21.3. IR (neat): 2937, 2811, 2359, 1789, 1345, 741 cm–1. LRMS (EI, 70 eV): m/z (%) = 288 (1) [M], 240 (12), 210 (13) 160 (6), 77 (100). ESI-HRMS: m/z calcd for C16H16O5 [M + H]+: 288.0997; found: 288.0992. Methyl 2-Isobutyryl-5-oxo-3-phenyl-2,5-dihydrofuran-2-carboxylate (3ah) Yield: 44.9 mg (78%); white solid; mp 110.3–112.0 1H NMR (400 MHz,CDCl3, 25 °C): δ = 7.60–7.40 (m, 2 H), 7.45–7.41 (m, 3 H), 6.55 (s, 1 H), 3.84 (s, 3 H), 3.09 (t, J = 6.0 Hz, 1 H), 1.23–1.21 (d, J = 8.0 Hz, 3 H), 1.01–0.99 (d, J = 8.0 Hz, 3 H). 13C NMR (75 MHz, CDCl3, 25 °C): δ = 204.68, 170.51, 165.49, 162.99, 131.86, 128.90, 128.71, 115.96, 92.92, 53.89, 36.56, 19.21, 19.17. IR (neat): 2957, 2851, 2359, 1776, 1255, 739 cm–1. LRMS (EI, 70 eV): m/z (%) = 274 (6) [M], 259 (14), 200 (37) 146 (100), 77 (30). ESI-HRMS: m/z calcd for C16H16O5 [M + H]+: 288.2951; found: 288.2946. 4-Acetyl-4-benzoyl-3-phenylcyclopent-2-enone (3ai) Yield 47.4 mg (75%); yellow solid; mp 52–55 °C. 1H NMR (400 MHz, CDCl3, 25 °C): δ = 7.89 (d, J = 8.0 Hz, 2 H), 7.62 (t, J = 10.0 Hz, 3 H),7.49–7.43 (m, 5 H), 6.67 (s, 1 H), 2.39 (s, 3 H). 13C NMR (100 MHz, CDCl3, 25 °C): δ = 170.51, 164.29, 134.08, 132.01, 129.70, 129.26, 128.87, 115.84, 24.78. IR (neat): 2925, 2854, 1770, 1693, 1450, 1266, 713, 685 cm–1. LRMS (EI, 70 eV): m/z (%) = 306 (0.02) [M], 218 (4), 189 (6), 173 (27), 158 (65), 105 (100). ESI-HRMS: m/z calcd for C20H17O3 [M + H]+: 306.3121; found: 306.0892