1,2-Cyclohexanedione → Methyl 3-acetyl-4,5,6,7-tetrahydrobenzo[c]thiophene-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Add methyl 2-(2-oxopropylthio)acetate (35.4 g, 183.2 mmol) to a freshly prepared solution of solid sodium (8.78 g, 381.5 mmol) in dry MeOH (300 mL) at 0° C., followed by addition of a solution of cyclohexane-1,2-dione (20 g, 152.6 mmol) in MeOH (30 mL). Stir the mixture at 0° C. for 30 min and then at 50-60° C. for additional 1.5 hour. Remove the solvent under vacuum and dilute the residue with water (100 mL). Extract the aqueous mixture with ethyl acetate (100 mL×3). The combined organic layers are washed with brine, dried over anhydrous Na2SO4, and evaporated under vacuum. Purify the residue by a flash column on silica gel eluting with PE:EtOAc (50:1 to 30:1) to afford methyl 3-acetyl-4,5,6,7-tetrahydrobenzo[c]thiophene-1-carboxylate as a white solid (10 g, 27.6%). MS (m/z): 239 (M+1).

Provenance & Evidence