Decarboxylative Arylation of α,β‐Unsaturated Carboxylic Acids Using Aryl Triazenes by Copper/Ionic Liquid Combination in PEG‐400

Abstract

A practical method for the construction of stilbene derivatives has been developed via catalytic cross‐coupling of cinnamic acids with aryl triazenes. The methodology offers high stereoselectivity and is endowed with broad substrate scope, high yield, and significant functional group tolerance.

New Uncharged 2-Thienostilbene Oximes as Reactivators of Organophosphate-Inhibited Cholinesterases

“…The spectroscopic data for the geometrical isomers of compounds 1-6 were obtained from the 1 H NMR spectra of the mixtures. [28]: 404 mg (18.4%); Rf (petroleum ether) = 0.71; lyzer), equipped with an Nd:YAG laser operating at 355 nm with a firing rate of 200 Hz in the positive (H+) or negative (-H) ion reflector mode. The initial phosphonium salts were prepared in the laboratory from the corresponding bromides, while the other starting compounds used were purchased chemicals.…”

“…(4-methylstyryl)thiophene (cis-1)[28]: 404 mg (18.4%); Rf (petroleum ether) = 0.71;1 H NMR (CDCl3, 600 MHz) δ/ppm: 7.14-7.21 (m, 4H, HA, HB), 7.09 (d, 1H, J = 4.7 Hz, HG),6.98 (d, 1H, J = 3.6 Hz, HE),6.89 (dd, 1H, J = 4.7; 3.6 Hz, HF),6.66 (d, 1H, J = 12.1 Hz, HC/D),6.54 (d, 1H, J = 12.1 Hz, HC/D), 2.37 (s, 3H, -CH3); trans-2-(4-methylstyryl)thiophene (trans-1)[28,29]: 810 mg (36.8%); Rf (petroleum ether) = 0.57;1 H NMR (CDCl3, 600 MHz) δ/ppm: 7.37 (d, 2H, J = 7.8 Hz, HA/B), 7.26 (d, 1H, J = 5.2 Hz, HG), 7.21-7.14 (m, 3H, HC/D, HA/B), 7.05 (d, 1H, J = 3.6 Hz, HE), 7.00 (dd, 1H, J = 5.2; 3.6 Hz, HF), 6.91 (d, 1H, J = 16.0 Hz, HC/D), 2.36 (s, 3H, -CH3); MS (ESI) m/z (%, fragment): 201 (100, M+H + ); HRMS (m/z) for C13H12S (obtained for the pure mixture of geometrical isomers): [M+H] + calcd = 201.0659, [M+H] + measured = 201.0660. cis-2-(4-methoxystyryl)thiophene (cis-2) [30]: 403 mg (17.0%); R f (petroleum ether/ diethyl ether (1%)) = 0.30; 1 H NMR (CDCl 3 , 600 MHz) δ/ppm: 7.29 (d, 2H, J = 8.7 Hz, H A/B ), 7.09 (d, 1H, J = 4.9 Hz, H G ), 6.98 (dd, 1H, J = 4.9; 3.6 Hz, H F ), 6.98 (d, 1H, J = 3.6 Hz, H E ), 6.87 (d, 2H, J = 8.7 Hz, H A/B ), 6.63 (d, 1H, J = 11.8 Hz, H C/D ), 6.51 (d, 1H, J = 11.8 Hz, H C/D ), 3.83 (s, 3H, -OCH 3 ); trans-2-(4-methoxystyryl)thiophene (trans-2) [29]: 803 mg (33.8%); R f (petroleum ether/ diethyl ether (1%)) = 0.23; 1 H NMR (CDCl 3 , 600 MHz) δ/ppm: 7.40 (d, 2H, J = 8.4 Hz, H A/B ), 7.15 (d, 1H, J = 4.9 Hz, H G ), 7.10 (d, 1H, J = 15.9 Hz, H C/D ), 7.02 (d, 1H, J = 3.6 Hz, H E ), 7.01 (d, 1H, J = 15.9 Hz, H C/D ), 6.89 (d, 2H, J = 8.4 Hz, H A/B ), 6.88 (dd, 1H, J = 4.9; 3.6 Hz, H F ), 3.83 (s, 3H, -OCH 3 ); MS (ESI) m/z (%, fragment): 217 (100, M+H + ); HRMS (m/z) for C 13 H 12 OS (obtained for the pure mixture of geometrical isomers): [M+H] + calcd = 217.0609, [M+H] + measured = 217.0605.ether/diethyl ether (1%)) = 0.23; 1 H NMR (CDCl3, 600 MHz) δ/ppm: 7.40 (d, 2H, J = 8.4 Hz, HA/B), 7.15 (d, 1H, J = 4.9 Hz, HG), 7.10 (d, 1H, J = 15.9 Hz, HC/D), 7.02 (d, 1H, J = 3.6 Hz, HE), 7.01 (d, 1H, J = 15.9 Hz, HC/D), 6.89 (d, 2H, J = 8.4 Hz, HA/B), 6.88 (dd, 1H, J = 4.9; 3.6 Hz, HF), 3.83 (s, 3H, -OCH3); MS (ESI) m/z (%, fragment): 217 (100, M+H + ); HRMS (m/z) for C13H12OS (obtained for the pure mixture of geometrical isomers): [M+H] + calcd = 217.0609, [M+H] + measured = 217.0605. cis-2-(4-chlorostyryl)thiophene (cis-3): 591 mg (24.4%); Rf (petroleum ether) = 0.75; 1 H NMR (CDCl3, 600 MHz) δ/ppm: 7.33-7.28 (m, 4H, HA/B), 7.12 (d, 1H, J = 5.0 Hz, HG), 6.97 (d, 1H, J = 3.6 Hz, HE), 6.90 (dd, 1H, J = 5.0; 3.6 Hz, HF), 6.71 (d, 1H, J = 11.8 Hz, HC/D), 6.50 (d, 1H, J = 11.8 Hz, HC/D); trans-2-(4-chlorostyryl)thiophene (trans-3) [29]: 629 mg (26.0%); Rf (petroleum ether) = 0.65; 1 H NMR (CDCl3, 600 MHz) δ/ppm: 7.39 (d, 2H, J = 8.5 Hz, HA/B), 7.33-7.28 (m, 2H, HA/B), 7.21 (d, 1H, J = 5.0 Hz, HG), 7.20 (d, 1H, J = 16.2 Hz, HC/D), 7.08 (d, 1H, J = 3.4 Hz, HE), 7.01 (dd, 1H, J = 5.0; 3.4 Hz, HF), 6.87 (d, 1H, J = 16.2 Hz, HC/D); MS (ESI) m/z (%, fragment): 221/223 (80, M+H + ), 186 (100); HRMS (m/z) for C12H9ClS (obtained for the pure mixture of geometrical isomers): [M+H] + calcd = 221.0112, [M+H] + measured = 221.0114. cis-4-(2-(thiophen-2-yl)vinyl)benzonitrile (cis-4): 831 mg (35.8%); Rf (petroleum ether/diethyl ether (30%)) = 0.52; 1 H NMR (CDCl3, 600 MHz) δ/ppm: 7.63 (d, 2H, J = 8.0 Hz, HA/B), 7.47 (d, 2H, J = 8.0 Hz, HA/B), 7.14 (d, 1H, J = 4.9 Hz, HG), 6.98 (d, 1H, J = 3.6 Hz, HE), 6.92 (dd, 1H, J = 4.9; 3.6 Hz, HF), 6.79 (d, 1H, J = 12.0 Hz, HC/D), 6.52 (d, 1H, J = 12.0 Hz, HC/D); tr...…”

Recent advances in synthesis of stilbene derivativesviacross-coupling reaction

“…Construction of stilbene derivatives 9c from α,β-unsaturated carboxylic acids 9a and aryl triazenes 9b through a catalytic decarboxylative cross-coupling process by using copper/ionic liquid combination in PEG-400 was developed by Singh and co-workers (Scheme 13). 31 The reaction proceeded through the formation of a diazonium salt. A plausible mechanism for this arylation of cinnamic acids with aryl triazenes is outlined in Scheme 14.…”

Custom-Made Pyrene Photocatalyst-Promoted Desulfonylation of Arylethenyl Sulfones Using Green-Light-Emitting Diodes

“…1 H NMR (CDCl 3 , 400 MHz):  = 7.12 (d, J = 16.6 Hz, 1 H), 7.20 (d, J = 16.6 Hz, 1 H), 7.30 (t, J = 7.5 Hz, 1 H), 7.39 (t, J = 7.5 Hz, 2 H), 7.54 (d, J = 7.5 Hz, 2 H), 7.61 (s, 4 H). trans-2-Chlorostilbene (3f) 28 Isolated by flash chromatography (hexane); yield: 40 mg (75%); white solid.…”