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Synlett 2023; 34(16): 1925-1929
DOI: 10.1055/s-0041-1738442
letter

Iodine-Catalyzed Simple and Efficient Synthesis of 1,3,5-Triarylbenzenes and 2,3-Dihydrobenzofuran Derivatives under Mild Reaction Conditions

Dong Cheng
,
Xiangzhen Meng∗
,
Dongmei Li
,
Sunying Jie
,
Yifan Liu
,
Xiaoqing Jiao
We acknowledge the Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province (gxgnfx2018035); the Innovation and Entrepreneurship Project of College Students in Anhui Province (DCJX-S17227577), and the Wanwei Technology Innovation Incubation Project.
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Abstract

The I2-catalyzed cyclization reaction of chalcones and 2-aryl propionaldehydes or isobutyraldehyde has been developed for the synthesis of 1,3,5-triarylbenzenes and 2,3-dihydrobenzofuran derivatives. This reaction tolerates a wide range of functional groups. Moreover, this method features an inexpensive catalyst and available starting materials.

Key words

1,3,5-triarylbenzenes - 2,3-dihydrobenzofuran scaffolds - chalcone - annulation - I2

Supporting Information

    Supporting information for this article is available online at https://doi.org/10.1055/s-0041-1738442.
  • Supporting Information


Publikationsverlauf

Eingereicht: 23. April 2023

Angenommen nach Revision: 10. Mai 2023

Artikel online veröffentlicht:
12. Juni 2023

© 2023. Thieme. All rights reserved

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  • References and Notes

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  • 11 General Procedure for the Synthesis of 1,3,5-Triarylbenzenes Chalcones 1 (0.5 mmol), 2-phenylpropanal 2 (5.0 mL), and I2 (38.1 mg, 0.25 mmol) were loaded into a 10 mL sealed tube. The reaction mixture was stirred at 110 ℃. After completion, the reaction was quenched by the addition of saturated aqueous Na2S2O3 (15 mL) and extracted with dichloromethane (3 × 10 mL). The combined organic extracts were washed with H2O (20 mL) and brine (20 mL), dried with anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (200–300 mesh) using PE/dichloromethane to give the product. 5′-Phenyl-1,1′:3′,1′′-terphenyl (3a) White solid; 1H NMR (500 MHz, CDCl3): δ = 7.79 (s, 3 H), 7.74–7.67 (m, 6 H), 7.48 (t, J = 7.6 Hz, 6 H), 7.44–7.32 (m, 3 H). 13C NMR (126 MHz, CDCl3): δ = 142.4, 141.2, 128.9, 127.6, 127.4, 125.2.
  • 12 Chalcones 1 (0.5 mmol), isobutyraldehyde 2 (5.0 mL), and I2 (63.3 mg, 0.25 mmol) were loaded into a 20 mL sealed tube. The reaction mixture was stirred at 100 ℃ for 12 h. After completion, the reaction was quenched by the addition of saturated aqueous Na2S2O3 (15 mL) and extracted with EtOAc (3 × 10 mL). The combined organic extracts were washed with H2O (20 mL) and brine (20 mL), dried with anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (200–300 mesh) using PE/Et2O to give the product. 2-Isopropyl-3,3-dimethyl-4,6-diphenyl-2,3-dihydrobenzofuran (4a) White solid; mp 157–163 ℃. 1H NMR (400 MHz, CDCl3): δ = 7.44–7.36 (m, 10 H), 6.66 (s, 1 H), 3.92 (d, J = 6.4 Hz, 1 H), 2.28 (s, 3 H), 2.21‒2.15 (m, 1 H), 1.25 (s, 3 H),1.22 (d, J = 4.4 Hz, 3 H), 1.17 (s, 3 H), 1.09 (d, J = 4.4 Hz, 3 H). 13C NMR (100 MHz, CDCl3): δ = 157.0, 141.4, 141.1, 140.8, 136.7, 132.9, 129.7, 129.5, 128.0, 127.5, 127.0, 126.7, 124.5, 116.5, 97.4, 45.5, 29.2, 27.4, 22.7, 20.7, 20.0, 12.9. IR (thin film): 3054, 3032, 2976, 2896, 1568, 1474, 1392, 985, 763. HRMS (ESI): m/z calcd for C26H29O [M + H]+: 357.2213; found: 357.2207.
  • 13 CCDC 22232941 (4b) and CCDC 2232940 (4i) contain the supplementary crystallographic data for this paper. These data can be obtained free charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/structures.