Triethylamine → methyl 5,6-dihydro-4H-cyclopenta[b]thiophene-2-carboxylate

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Reaction Steps

To a 100-mL round-bottom flask containing a solution of 2-chlorocyclopent-1-ene-1-carbaldehyde (1.2 g, 9.19 mmol, 1.00 equiv) and methyl 2-sulfanylacetate (1.17 g, 11.02 mmol, 1.20 equiv) in pyridine (10 mL) was added triethylamine (2 mL) dropwise at 0° C. The resulting solution was stirred for 1 h at room temperature. The reaction was then quenched by the addition of 2 mL of 48% aqueous KOH solution and diluted with 100 mL of water. The resulting solution was extracted with 3×100 mL of ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and concentrated under vacuum to give 1.3 g (78%) of methyl 4H,5H,6H-cyclopenta[b]thiophene-2-carboxylate as a yellow solid. MS (ES): m/z 183 (M+H)+.

Provenance & Evidence