Acetyl chloride → 1-(2,3-Dihydro-benzo[b]thiophen-5-yl)-ethanone

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,3-dihydro-benzo[b]thiophene (1.88 g, 13.8 mmol) in methylene chloride (20 mL) at −10° C. was added dropwise a solution of acetyl chloride (1.85 mL, 25.9 mmol) and aluminum chloride (1.84 g, 13.8 mmol) in methylene chloride (20 mL) keeping the temperature below −6° C. during the addition period. After the addition is complete the reaction mixture was stirred for an additional 30 min at −10° C. and then added ice (40 mL) and concentrated hydrochloric acid (6 mL) and extracted with methylene chloride (3×20 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Purification on an AnaLogix Intelliflash system (80 g column, 10% diethyl ether/hexanes) afforded 1-(2,3-dihydro-benzo[b]thiophen-5-yl)-ethanone (1.93 g, 78%) as a clear colorless oil.

Provenance & Evidence