2',3'-d]thiophene synthesis

Yield:-

Reaction Conditions:

with tetrakis(triphenylphosphine) palladium⁽⁰⁾;caesium carbonate in tetrahydrofuran;water;toluene; for 8 h;Inert atmosphere;Reflux;Suzuki-Miyaura Coupling;

Steps:

2.1.1 General

General procedure: The outline of our synthetic routes to the 6 compounds listed in Fig. 1 is shown in Scheme 1. They were synthesized by Suzuki-Miyaura coupling of 2,6-dibromodithieno[3,2-b:2′,3′-d]thiophene each with the corresponding boronic acid. Compounds 5 and 7 in Fig. 1 were also synthesized by Suzuki-Miyaura coupling of 3,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)dibenzo[b,d]thiophene and 2,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)dithieno[3,2-b:2′,3′-d]thiophene with 2′-iodo-1,1′:3′,1″-terphenyl, respectively. The typical procedure is following. A mixture of 2,6-dibromo-dithieno[3,2-b:2′,3′-d]thiophene (174.0 mg, 0.5 mmol), boronic acid of counterpart (1.5 mmol), tetrakis (triphenylphosphine) palladium (81.5 mg, 0.08 mmol) and Cs₂CO₃ (2.0 mL, 2.0 M in aqueous) in 8 mL solvent of toluene: THF = 1:1 was stirred at reflux temperature for 8 h. All reactions were carried out under nitrogen atmosphere with anhydrous solvents. The mixture was poured into water (30 mL) and extracted with CH₂Cl₂ (20 mL × 3). The combined extract was washed with brine (40 mL), dried (Na₂SO₄), and concentrated in vacuo. Column chromatography on silica gel eluted with CHCl₃:toluene = 1:1. All compounds were characterized by ¹H and ¹³C NMR and mass spectroscopy.

References:

Okada, Shinjiro;Yamada, Kenji [Journal of Molecular Structure,2013,vol. 1037,p. 256 - 263]