Trifluoromethanesulfinic Acid Derivatives as Nucleophilic Trifluoromethylating Reagents

Abstract

Secondary trifluoromethanesulfinamides and alkyl tri­fluoromethanesulfinates can be used as nucleophilic trifluoromethylating reagents towards various electrophiles by action of potassium tert-butoxide.

Key words

trifluoromethylation - trifluorosulfinamide - fluorinated compounds - trifluoromethylcarbinols - tetrahedral intermediate

References

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7

Typical Procedure: To a solution of 2a (1 mmol) and the electrophile (1 mmol) in THF (1 mL), cooled at 0 °C, was dropped a 1 M solution of t-BuOK in THF (1 mL). The temperature is allowed to rise to r.t. over 1 h.. Then, the crude mixture was hydrolyzed by 1 M HCl (1 mL) overnight and extracted with diethyl ether. The organic phase was dried over Na₂SO₄ and the solvent was evaporated in vacuo. The crude products were purified by chromatography over silica gel.
Spectral Data: Compound 3c: ¹H NMR (300MHz, CDCl₃): δ = 7.64 (s, 1 H), 7.22-7.43 (m, 8 H), 6.88 (d, 1 H, J = 16 Hz), 6.71 (d, 1 H, J = 16 Hz), 2.79 (s, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 137.6, 135.7, 133.7, 129.0, 128.9, 128.8, 128.5, 127.1, 127.0 (q, J = 1.2 Hz), 126.6, 125.2 (q, J = 286 Hz), 80.3 (q, J = 28.5 Hz). ¹⁹F NMR (282MHz, CDCl₃): δ = -78.97. Compound 3e: ¹H NMR (300MHz, CDCl₃): δ = 7.84 (s, 1 H), 7.75 (t, 2 H, J = 8.2 Hz), 7.53 (d, 1 H, J = 8.5 Hz), 7.18 (m, 2 H), 5.16 (q, 1 H, J = 6.7 Hz), 3.93 (s, 3 H), 3.23 (s, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 158.7, 135.4, 130.2, 129.6 (q, J = 1.2 Hz), 128.8, 127.7, 127.6, 124.3, 124.9 (q, J = 282.0 Hz), 119.8, 106.1, 73.4 (q, J = 32.0 Hz), 55.8. ¹⁹F NMR (282MHz, CDCl₃): δ= -78.17 (d, J = 6.7 Hz). Compound 3f: ¹H NMR (300MHz, CDCl₃): δ = 9.08 (d, 1 H, J = 1.5 Hz), 8.53 (d, 1 H, J = 1.5 Hz), 8.11 (dd, 1 H, J = 8.4 Hz, J = 1.2 Hz), 8.05 (dd, 1 H, J = 8.2 Hz, J = 1.3 Hz), 7.82 (ddd, 1 H, J = 8.4 Hz, J = 6.8 Hz, J = 1.6 Hz), 7.66 (ddd, 1 H, J = 8.2 Hz, J = 6.8 Hz, J = 1.2 Hz), 6.49 (s, 1 H), 5.62 (q, 1 H, J = 7.1 Hz). ¹³C NMR (75 MHz, CDCl₃): δ = 150.0 (q, J = 1.5 Hz), 148.7, 135.5, 130.4, 129.5, 129.3 (q, J = 1.5 Hz), 128.7, 127.5, 125.4 (q, J = 281.9 Hz), 123.6, 70.4 (q, J = 31.7 Hz). ¹⁹F NMR (282MHz, CDCl₃): δ =
-78.73 (d, ³ J _F-H = 7.1 Hz).