Novel SF₅-Anilines and SF₅-Aryl Ethers from SF₅-Substituted Potassium Aryl Trifluoroborates

Abstract

The copper-catalyzed coupling of SF₅-substituted potassium aryl trifluoroborates with amines and alcohols is reported. This method provides a simple access to novel 3-pentafluorosulfanyl-substituted anilines and aryl ethers, which are potential important building blocks for drug discovery and agrochemicals.

Key words

pentafluorosulfanyl - copper - arenes - ethers - anilines

• References and Notes

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• 16 General Procedure for the Preparation of SF₅-Anilines A suspension of 1a (118.0 mg, 0.347 mmol, 2.0 equiv), Cu(OAc)₂·H₂O (3.5 mg, 0.017 mmol, 0.1 equiv), Et₃N (24 μL, 0.174 mmol, 1.0 equiv) and powdered 4 Å MS (230 mg) in 1.7 mL DCE was stirred for 5 min at r.t. Then 4-bromoaniline (31.1 mg, 96%, 0.174 mmol) was added, a condenser was set up, and the reaction mixture was stirred at 85 °C under an atmosphere of oxygen (balloon) for 16 h. The reaction mixture was cooled down to r.t., filtered through a pad of Celite, and concentrated in vacuo. Purification was made by column chromatography (hexane–toluene, 8:2 to 7:3) to afford the aniline 3a (50.1 mg, 0.124 mmol, 71%). N-(4-Bromophenyl)-3-methoxy-5-(pentafluorosulfanyl)aniline (3a) R_f = 0.25 (hexanes–EtOAc, 9:1). ¹H NMR (300 MHz, CDCl₃): δ = 7.47–7.35 (m, 2 H), 7.02–6.93 (m, 3 H), 6.83 (t, J = 2.0 Hz, 1 H), 6.67 (t, J = 2.1 Hz, 1 H), 5.79 (s, 1 H), 3.80 (s, 3 H). ¹³C NMR (101 MHz, CDCl₃): δ = 160.4, 155.7 (p, ² J _CF = 16.8 Hz), 144.4, 140.8, 132.7, 121.0, 115.0, 107.7 (p, ³ J _CF = 4.8 Hz), 105.4, 104.6 (p, ³ J _CF = 4.6 Hz), 55.9. ¹⁹F NMR (282 MHz, CDCl₃): δ = 84.4 (app m), 62.4 (d, ² J _FF = 148.4 Hz). IR (neat): 3406, 2940, 2841, 1608, 1586, 1487, 1256, 1197, 1114, 896, 832, 768, 660, 595 cm^–1. HRMS (EI): m/z calcd for [C₁₃H₁₁BrF₅NOS]⁺: 402.9660; found: 402.9663.
• 17 General Procedure for the Preparation of SF₅-Aryl Ethers A suspension of 1a (126.0 mg, 0.372 mmol, 2.0 equiv), Cu(OAc)₂·H₂O (37.0 mg, 0.186 mmol, 1.0 equiv), DMAP (4.5 mg, 0.037 mmol, 0.2 equiv), and powdered 4 Å MS (200 mg) in 1.8 mL DCE was stirred for 5 min to r.t. Then ethyl 4-hydroxybenzoate (31.2 mg, 99%, 0.186 mmol) was added, a condenser was set up, and the reaction mixture was stirred at 60 °C under an atmosphere of oxygen (balloon) for 24 h. The reaction mixture was cooled down at r.t., filtered through a pad of Celite, and concentrated under vacuo. Purification was made by preparative TLC (hexanes–EtOAc, 95:5) to afford the aryl ether 5c (60.2 mg, 0.151 mmol, 80%). Ethyl 4-[3-Methoxy-5-(pentafluorosulfanyl)phenoxy]benzoate (5c) R_f = 0.30 (hexanes–EtOAc, 9:1). ¹H NMR (400 MHz, CDCl₃): δ = 8.06 (d, J = 8.8 Hz, 2 H), 7.09 (t, J = 2.1 Hz, 1 H), 7.06–7.01 (m, 3 H), 6.71 (t, J = 2.2 Hz, 1 H), 4.38 (q, J = 7.2 Hz, 2 H), 3.82 (s, 3 H), 1.40 (t, J = 7.1 Hz, 3 H). ¹³C NMR (101 MHz, CDCl₃): δ = 166.0, 160.7, 160.3, 156.9, 155.4 (app m), 132.0, 126.3, 118.2, 109.9 (p, ³ J _CF = 4.7 Hz), 108.3 (m, 2 C), 61.2, 56.1, 14.5. ¹⁹F NMR (282 MHz, CDCl₃): δ = 83.7 (app m), 62.6 (d, ² J _FF = 149.8 Hz). IR (neat): 3407, 3104, 1714, 1600, 1588, 1504, 1467, 1448, 1274, 1222, 1162, 1147, 1099, 894, 835, 814, 760, 662, 597 cm^–1. HRMS (EI): m/z calcd for [C₁₆H₁₅F₅O₄S]⁺: 398.0606; found: 398.0603.