One-Pot Synthesis of Substituted Thiophene and Furan Derivatives from Terminal Alkynes

Synthesis of disubstituted furans catalysed by [(AuCl)2(μ-bis(phosphino)metallocene)] and Na[BArF24]

“…In the first report of the 2,5-isomer, it was prepared by the reaction of 1,4-di-pyridine-2-yl-1,4-butanedione with polyphosphoric acid. 77 The other reports prepared the compound from 2-ethynylpyridine 78 or 1-bromo-2-(2-ethylnylpyridine) 79 using copper( i ) iodide as the catalyst. The exact role of the gold catalyst in preparing the unsymmetric 2,4-isomer and the surprising efficiency of the dfurpf catalyst are unclear and warrant further investigation.…”

Cobalt-Catalyzed Glaser-type Homocoupling Reaction

“…3,2′:5′,3′′-Terthiophene (42) 32 Purification via column chromatography (PE) afforded 42 (36.6 mg, 74%) as a white solid. 1 H NMR (500 MHz, CDCl 3 ):  = 7.40-7.34 (m, 4 H), 7.32 (dd, J = 5.0, 1.3 Hz, 2 H), 7.13 (s, 2 H).…”

“…2,2′:5′,2′′-Terthiophene (43) 32 Purification via column chromatography (PE) afforded 43 (38.2 mg, 77%) as a pale yellow solid.…”

Trithiocarbonate Anion as a Sulfur Source for the Synthesis of 2,5-Disubstituted Thiophenes and 2-Substituted Benzo[b]thiophenes

“…2,5-Diheptylthiophene (2o). 43 The product was isolated by column chromatography (hexane) as a brownish oil (28 mg, 40% yield). 1 H NMR (400 MHz, CDCl 3 ): δ 6.54 (s, 2H), 2.73 (t, J = 7.6 Hz, 4H), 1.72−1.58 (m, 4H), 1.…”

“…2-(Benzo [b]thiophen-2-yl)pyridine (5h). 43 The product was isolated by column chromatography (hexane/ethyl acetate 90:10) as a yellow solid (27 mg, 51% yield); mp 120−122 °C. 1 H NMR (400 MHz, CDCl 3 ): δ 8.63 (ddd, J = 4.9, 1.7, 1.0 Hz, 1H), 1H),7.83 (s,1H),2H),7.72 (td,J = 7.7,1.7 Hz,1H),2H),7.20 (ddd,J = 7.4,4.9,1.2 Hz,1H).…”