Recent advances in transition-metal catalyzed directed C–H functionalization with fluorinated building blocks

Abstract

Increasing demand for the development of unprecedented routes to access fluorinated molecules has led researchers to do intriguing research around the world. In this context, the use of fluorinating reagents...

Rhodium(III)-Catalyzed Conjugate Addition of β-CF3-Enones with Quinoline N-Oxides

“…19.7 mg (23%); eluent (SiO 2 , nhexanes/acetone = 2:1); red oil; 1 H NMR (400 MHz, CD 3 COCD 3 ) δ 8. 48 (s,1H),1H),8.15 (d,J = 8.0 Hz,1H),7.98 (td,J = 10.0,5.2 Hz,1H),7.76 (d,J = 8.0 Hz,1H),1H),7.46 (d,J = 8.0 Hz,1H),2H),1H),1H),4H),3.86 (s,3H),3.62 (dd,J = 16.8,4.8 Hz,1H); 13 C{ 1 H} NMR (100 MHz, CD 3 COCD 3 ) δ 190. 7,158.6,138.5,138.2,137.6,137.0,135.2,132.8 (d,J = 2.5 Hz),132.0,130.1,128.7 (q,J = 277.6 Hz),127.2,126.2,123.9,122.9 (d,J = 5.8 Hz),122.7,116.7,110.9,108.0,56.1,40.1,39.2 (q, J C−F = 26.6 Hz), 33.7; 19 F NMR (376 MHz, CD 3 COCD 3 ) δ −69.0 (d, J = 10.2 Hz); IR (KBr) υ 3109,2924,2854,…”

“…1, 158.6, 137.4, 137.0, 135.2, 132.8 (d, J C−F = 2.7 Hz), 128.5 (q, J C−F = 277. 4 Hz),125.8,123.6,122.8,108.0,56.2,50.8,acetone = 4:1); red oil; 1 H NMR (400 MHz, CD 3 COCD 3 ) δ 8.01 (td,J = 10.0,4.8 Hz,1H),7.92 (d,J = 8.0 Hz,2H),7.66 (d,J = 8.4 Hz,1H),2H),3H),4.05 (dd,J = 18.0,10.0 Hz,1H),3.88 (s,3H),1H), 2.53 (s, 3H), 2.38 (s, 3H); 13 C{ 1 H} NMR (100 MHz,CDCl 3 ) δ 195.1,157.0,146.4,144.2,136.6,134.1,132.7,132.0 (d,129.4,128.2,127.5 (q, J C−F = 278.1 Hz), 125. 0, 123.6, 122.7, 106.7, 55.5, 39.7, 38.6 (q, J C−F = 26.…”

“…4,164.7,162.2,159.7,138.9,135.3,134.9 (d,131.3,130.5,130.4,128.4 (q, J C−F = 278.0 Hz), 126.2 (q, J C−F = 277.4 Hz), 123.5, 120.9 (d, J C−F = 26.9 Hz), 114.6, 113.5 (d, J C−F = 21.7 Hz), 56.0, 39.4 (q, J C−F = 26.2 Hz); 19 F NMR (376 MHz, CDCl 3 ) δ −68.5 (d, J = 9.8 Hz), −110.8 (t, J = 8.6 Hz); IR (KBr) υ 3008,2924,2854,1677,1600,1578,1512,1422,1377,1364,1317,1260,1184,1172,1104 1,butan-2-yl)quinoline 1-oxide (4k). 34.7 mg (46%); eluent (SiO 2 , n-hexanes/acetone = 3:1); red oil; 1 H NMR (400 MHz, CD 3 COCD 3 ) δ 8.50 (d, J = 6.8 Hz, 1H), 4H),1H),7.76 (dd,J = 8.4,2.8 Hz,1H),1H),7.30 (d,J = 8.0 Hz,2H),4.17 (dd,J = 18.0,10.4 Hz,1H),3.89 (dd,J = 18.0,4.4 Hz,1H), 2.38 (s, 3H); 13 C{ 1 H} NMR (100 MHz, CD 3 COCD 3 ) δ 195. 6, 161.9, 160.0, 144.9, 138.9, 135.5, 135.1, 134.9 (d , 2923, 1686, 1626, 1607, 1579, 1378, 1366, 1320, 1259, 1211, 1184, 1161, 1104 1,benzo- [f]quinoline 4-oxide (4l).…”

“…For flash column chromatography, E. Merck Kieselgel 60 (230−400 mesh) was used. Nuclear magnetic resonance spectra ( 1 H, 13 C, and 19 F NMR) of synthesized compounds were recorded in either CD 3 COCD 3 or CDCl 3 on Bruker Unity 400, 500, and 700 MHz spectrometers, and chemical shifts are reported as parts per million (ppm). Resonance patterns are reported with the notations s (singlet), d (doublet), t (triplet), q (quartet), dd (doublet of doublets), dt (doublet of triplets), td (triplet of doublets), and m (multiplet).…”

“…7 Alternatively, substantial efforts have been also focused toward the development of synthetic methods using CF 3 -containing building blocks, i.e., trifluoromethyl ketones, 8 trifluoroacetoa-cetate, 9 trifluoromethylated alkynes, 10 α,β-unsaturated trifluoromethyl ketones, 11 α-trifluoromethylated allylic carbonates, 12 etc. 13 In particular, β-CF 3 -α,β-unsaturated ketones have been intensively explored for Michael reactions, Friedel−Crafts-type reactions, cycloaddition/annulation reactions, metal-mediated 1,4-additions, etc. 14 Recently, β-CF 3 -α,β-unsaturated ketones have been also employed in the catalytic C−H functionalizations.…”