Synlett 2018; 29(05): 621-626
DOI: 10.1055/s-0036-1591893
letter
© Georg Thieme Verlag Stuttgart · New York

Carbonylative Synthesis of Thiochromenones via Palladium-Catalyzed tert-Butyl Isocyanide Insertion

Fang-Ling Zhang
College of Pharmaceutic Science, Soochow University, SuZhou, 215123, P. R. of China   Email: zhuyongming@suda.edu.cn
,
Zhen-Bang Chen
College of Pharmaceutic Science, Soochow University, SuZhou, 215123, P. R. of China   Email: zhuyongming@suda.edu.cn
,
Kui Liu
College of Pharmaceutic Science, Soochow University, SuZhou, 215123, P. R. of China   Email: zhuyongming@suda.edu.cn
,
Qing Yuan
College of Pharmaceutic Science, Soochow University, SuZhou, 215123, P. R. of China   Email: zhuyongming@suda.edu.cn
,
Qing Jiang
College of Pharmaceutic Science, Soochow University, SuZhou, 215123, P. R. of China   Email: zhuyongming@suda.edu.cn
,
Yong-Ming Zhu*
College of Pharmaceutic Science, Soochow University, SuZhou, 215123, P. R. of China   Email: zhuyongming@suda.edu.cn
› Author Affiliations
Further Information

Publication History

Received: 16 October 2017

Accepted after revision: 18 December 2017

Publication Date:
23 January 2018 (online)


Abstract

A flexible and efficient carbonylative synthesis of thiochromenones from the commercially available materials by utilizing tert-butyl isocyanide as carbonyl source has been developed. This methodology efficiently constructs thiochromenones in moderate to excellent yields with the advantages of wide range of substrates and being applicable to library synthesis.

Supporting Information

 
  • References and Notes

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  • 23 General Procedure In a 15 mL sealed tube equipped with a magnetic stirring bar were added 1 (1 mmol), 2 (0.8 mmol), tert-butyl isocyanide (1.2 mmol, 136 μL), Pd(OAc)2 (0.03 mmol, 7 mg), DPEPhos (0.06 mmol, 32 mg), Cs2CO3 (0.8 mmol, 261 mg), and anhydrous DMF (2.0 mL). The tube was purged with argon, and the contents were stirred at 100 °C for 2 h. Then Na2S·9H2O (1.2 mmol, 240 mg) was added for 2 h. After reaction completion, the mixture was filtered through a pad of Celite, and DMF was removed by a vacuum. The combined filtrates were refluxed in THF (15 mL) and oxalic acid (1 M, 3 mL) for 8 h. The solvents were removed under reduced pressure, then poured into brine (20 mL) and extracted by ethyl acetate (3 × 30 mL). The combined organic layers were dried (Na2SO4) and evaporated. The residue was purified on a silica gel column using petroleum ether/ethyl acetate as the eluent to give the pure target product.
  • 24 2-(2-Fluorophenyl)-4H-thiochromen-4-one (3j) Yellow solid (116 mg, 57%); mp 128–130 °C. 1H NMR (400 MHz, CDCl3): δ = 8.56 (d, J = 7.9 Hz, 1 H), 7.65 (d, J = 3.1 Hz, 2 H), 7.56 (dd, J = 13.0, 5.6 Hz, 2 H), 7.48 (dd, J = 13.2, 7.1 Hz, 1 H), 7.29 (d, J = 7.5 Hz, 1 H), 7.21 (d, J = 12.4 Hz, 2 H). 13C NMR (101 MHz, CDCl3): δ = 180.6 (s), 160.6 (s), 158.1 (s), 147.1 (s), 138.2 (s), 132.2 (d, J C-F = 8.4 Hz), 131.8 (s), 131.0 (s), 130.3 (d, J C-F = 1.9 Hz), 128.8 (s), 128.0 (s), 127.0 (d, J C-F = 3.7 Hz), 126.5 (s), 124.9 (d, J C-F = 3.8 Hz), 124.6 (d, J C-F = 13.1 Hz), 117.0 (s), 116.8 (s). IR (KBr): 1627, 1593, 1439, 1325, 1098, 758, 732, 685 cm–1. HRMS: m/z calcd for C15H10FOS [M + H]+: 257.0437; found: 257.0428.
  • 25 2-(Thiophen-3-yl)-4H-thiochromen-4-one (3n) Yellow solid (78 mg, 40%); mp 135–140 °C. 1H NMR (400 MHz, CDCl3): δ = 8.53 (d, J = 8.0 Hz, 1 H), 7.78 (s, 1 H), 7.65–7.43 (m, 6 H). 13C NMR (101 MHz, CDCl3): δ = 181.2 (s), 147.0 (s), 137.8 (s), 137.3 (s), 131.8 (s), 131.2 (s), 128.7 (s), 127.9 (s), 127.7 (s), 126.5 (s), 125.4 (s), 125.2 (s), 122.2 (s). IR (KBr): 3094, 1605, 1582, 1543, 1329, 1101, 774, 738, 631 cm–1. HRMS: m/z calcd for C13H9OS2 [M + H]+: 245.0096; found: 245.0093.
  • 26 8-Fluoro-2-(p-tolyl)-4H-thiochromen-4-one (5a) Yellow solid (143 mg, 66%); mp 160–164 °C. 1H NMR (400 MHz, CDCl3): δ = 8.35 (d, J = 8.0 Hz, 1 H), 7.62 (d, J = 8.0 Hz, 2 H), 7.52 (dd, J = 13.4, 7.9 Hz, 1 H), 7.39 (t, J = 8.7 Hz, 1 H), 7.32 (d, J = 7.8 Hz, 2 H), 7.24 (s, 1 H), 2.44 (s, 3 H). 13C NMR (101 MHz, CDCl3): δ = 180.2 (s), 159.3 (s), 156.8 (s), 152.2 (s), 141.8 (s), 133.8 (s), 132.7 (s), 132.6 (s), 130.2 (s), 127.9 (d, J C-F = 7.8 Hz), 127.0 (s), 124.3 (s), 123.0 (s), 117.2 (d, J C-F = 19.6 Hz), 21.5 (s). IR (KBr): 2922, 1620, 1601, 1549, 1247, 1129, 819 798, 709 cm–1. HRMS: m/z calcd for C16H12FOS [M + H]+: 271.0594; found: 271.0598.
  • 27 N-(tert-Butyl)-1-(2-fluorophenyl)-3-phenylprop-2-yn-1-imine (8) Yellow oil. 1H NMR (400 MHz, CDCl3): δ = 7.67 (t, J = 8.6 Hz, 1 H), 7.53 (d, J = 7.8 Hz, 2 H), 7.43–7.33 (m, 4 H), 7.17 (t, J = 7.5 Hz, 1 H), 7.13–7.05 (m, 1 H), 1.58 (s, 9 H). 13C NMR (101 MHz, CDCl3): δ = 161.9 (s), 159.4 (s), 144.6 (s), 133.4 (s), 131.8 (s), 131.0 (d, J C-F = 8.4 Hz), 130.4 (d, J C-F = 2.4 Hz), 129.8 (s), 129.4 (d, J C-F = 11.0 Hz), 128.7 (s), 124.2 (d, J C-F = 3.7 Hz), 122.0 (s), 116.5 (s), 116.3 (s), 98.9 (d, J C-F = 2.9 Hz), 85.0 (s), 57.9 (s), 29.6 (s). IR (KBr): 2968, 1609, 1590, 1485, 1305, 1222, 752, 648. HRMS: m/z calcd for C19H18FN [M + H]+: 280.1502; found: 280.1509.