Synlett 2024; 35(09): 1057-1061
DOI: 10.1055/a-2225-8858
cluster
Chemical Synthesis and Catalysis in Germany

Chemoselective Vicinal Dichlorination of Alkenes by Iron Ligand-to-Metal Charge-Transfer Catalysis

Jessica Stahl
Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany
,
Thilo Reiter
Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany
,
Burkhard König
› Author Affiliations
The work was supported by the DFG-funded Collaborative Research Center ‘Assembly Controlled Chemical Photocatalysis’ (TRR 325 – 444632635). J.S. thanks the Studienstiftung des Deutschen Volkes for a Ph.D. stipend.


Abstract

We report the photocatalytic functionalization of terminal alkenes to vicinal dichlorides by using visible light and FeCl3 as a catalyst, LiCl as a chloride source, and air as an oxidant. The transformation is proposed to be initiated by ligand-to-metal charge-transfer bond homolysis of a Fe–Cl bond, giving a highly reactive chloride radical able to initiate the functionalization of olefins. The process shows high chemoselectivity and broad functional-group tolerance with yields of up to 94% under mild conditions.

Supporting Information



Publication History

Received: 26 October 2023

Accepted after revision: 11 December 2023

Accepted Manuscript online:
11 December 2023

Article published online:
18 January 2024

© 2024. Thieme. All rights reserved

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

 
  • References and Notes

  • 1 Fauvarque J. Pure Appl. Chem. 1996; 68: 1713
  • 2 Baldwin RT. J. Chem. Educ. 1927; 4: 313
  • 3 Rajkumar D, Kim JG. J. Hazard. Mater. 2006; 136: 203
  • 4 Morosin B. J. Chem. Phys. 1968; 49: 3007
  • 5 Recio JM, Pendás AM, Francisco E, Flórez M, Luaña V. Phys. Rev. B 1993; 48: 5891
  • 6 Dreher E.-L, Torkelson TL, Beutel KK, Myers JD, Lübbe T, Kreiger S, Pottenger LH. In Ullmann’s Encyclopedia of Industrial Chemistry . Wiley-VCH; Weinheim: 2014. DOI: 10.1002/14356007.o06_o01.pub2
  • 7 Achanta S, Jordt S.-E. Toxicol. Mech. Methods 2021; 31: 244
  • 8 Lian P, Long W, Li J, Zheng Y, Wan X. Angew. Chem. Int. Ed. 2020; 59: 23603
  • 9 Kochi JK. J. Am. Chem. Soc. 1962; 84: 2121
  • 10 Feng G, Wang X, Jin J. Eur. J. Org. Chem. 2019; 6728
  • 11 Chen J, Browne WR. Coord. Chem. Rev. 2018; 374: 15
  • 12 Wedepohl KH. In Elements and Their Compounds in the Environment: Occurrence, Analysis and Biological Relevance, 2nd ed., Vol. 1, Chap. 1. Merian E, Anke M, Ihnat M, Stoeppler M. Wiley-VCH; Weinheim: 2004: 2
  • 13 Fürstner A. ACS Cent. Sci. 2016; 2: 778
  • 14 Vogler A, Kunkely H. Coord. Chem. Rev. 2000; 208: 321
  • 15 Inoue H, Tamaki K, Komakine N, Imoto E. Bull. Chem. Soc. Jpn. 1967; 40: 875
  • 16 Wang X, Shi C, Yang M, Ma Y, Chen Y, Lu T, Tang W, Feng J. Asian J. Org. Chem. 2023; 12: e202300077
  • 17 Treacy SM, Rovis T. J. Am. Chem. Soc. 2021; 143: 2729
  • 18 Ding L, Niu K, Liu Y, Wang Q. ChemSusChem 2022; 15: e202200367
  • 19 Fleischmann S, Percec V. J. Polym. Sci., Part A: Polym. Chem. 2010; 48: 4889
  • 20 Dey D, Patra M, Al-Hunaiti A, Yadav HR, Al-mherat A, Arar S, Maji M, Choudhury AR, Biswas B. J. Mol. Struct. 2019; 1180: 220
  • 21 Bian K.-J, Kao S.-C, Nemoto D, Chen X.-W, West JG. Nat. Commun. 2022; 13: 7881
  • 22 Preparative-Scale Iron-Catalyzed Dichlorination of Alkenes; General Procedure After successful screening at a 0.1 mmol scale, the preparative-scale reactions were performed in 6–12 parallel vials to achieve good reproducibility. Each vial was equipped with a magnetic stirrer bar and charged the appropriate alkene ester starting material (0.20 mmol, 1.00 equiv), FeCl3 (0.04 mmol, 6.50 mg, 20.0 mol%), and LiCl (2.00 mmol, 85.0 mg, 10.0 equiv) in 9:1 AcOH–MeCN (0.5 mL). The glass vials were closed, and air was added by syringe through a semi-permeable septum in the cap of each vial. The vials were sealed with Parafilm and placed in the thermostatted (20 °C) metal block approximately 2 cm above the 390–395 nm light source, and the mixtures were irradiated for 3 h. The vials were then opened to air and their contents were combined, filtered through a thin layer of silica gel in a vacuum filtration device, washed with Et2O, and collected in a 100 mL round-bottomed flask. The solvent volume was reduced under reduced pressure and the residue was extracted with H2O (2 × 20 mL) and NaHCO3 (20 mL). The combined organic layers were dried (Na2SO4), filtered, and then concentrated in vacuum. The oily residue was dried under reduced pressure and purified by flash column chromatography (silica gel, 20% acetone–PE). The purity of the product was confirmed by 1H and 13C NMR analyses in CDCl3 with triphenylmethane as a standard. 3,4-Dichlorobutyl Benzoate (1a) Colorless oil; yield: 0.023 g (47%, 0.093 mmol). 1H NMR (300 MHz, CDCl3): δ = 8.12–7.99 (m, 2 H), 7.62–7.49 (m, 1 H), 7.47–7.35 (m, 2 H), 4.62–4.41 (m, 2 H), 4.26 (dddd, J = 9.5, 7.3, 5.0, 3.5 Hz, 1 H), 3.83 (dd, J = 11.4, 5.0 Hz, 1 H), 3.72 (dd, J = 11.4, 7.3 Hz, 1 H), 2.50 (dddd, J = 14.5, 8.9, 5.8, 3.4 Hz, 1 H), 2.11 (ddt, J = 14.6, 9.7, 4.9 Hz, 1 H). 13C NMR (75 MHz, CDCl3): δ = 166.3 (Cq), 133.2 (+), 129.9 (Cq), 129.6 (+), 128.5 (+), 61.4 (–), 57.6 (+), 48.3 (–), 34.3 (–). The spectroscopic results agreed well with those in the literature; see ref. 8.
  • 23 Lynn E, Kobe AK. Ind. eng. chem. 1954; 46: 633
  • 24 Sun X, Liu X, Qin Y, He Y, Su D, Song Li, Su Z. Ind. Eng. Chem. Res. 2019; 58: 5404