Short-RInChIKey=SA-FUHFF-UHFFFADPSC-UNWKVSDABP-UHFFFADPSC-NUHFF-NUHFF-NUHFF-ZZZ

2-Bromothiophene (1.48 g, 9.11 mmol, 2.20 equiv) and Magnesium (240 mg, 9.11 mmol, 2.20 equiv) were suspended in THF (10 mL) and the mixture was heated to 55 °C for 1 h. Copper(1+);bromide (1.31 g, 9.11 mmol, 2.20 equiv) and lithium;bromide (1.58 g, 18.2 mmol, 4.40 equiv) were dissolved in THF (20 mL). The Grignard-solution was cooled to 0 °C and oxalyl dichloride (525 mg, 355 μL, 4.14 mmol, 1.00 equiv) was added. The resulting solution was stirred for 30 min. and then quenched with saturated aqueous NH4CI (20 mL) and extracted with EtOAc (50 mL). The combined organic phases were dried over MgSO4 and concentrated under vacuum. The obtained crude product was purified via flash-chromatography on silica gel using cyclohexane/DCM 2:1. 1,2-Dithiophen-2-ylethane-1,2-dione (520 mg, 2.34 mmol, 57% yield) was isolated in yellow crystals.