Hydrochloric Acid → 3-Chloro-1-(5,5-dimethyl-5,6-dihydro-4H-cyclopenta[b]thiophen-2-yl)propan-1-one

Participants

Reaction Conditions

Reaction Steps

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer was purged with nitrogen and charged with 113d (2.41 g, 10.0 mmol) and anhydrous THF (20 mL). The solution was cooled to −70° C., and 1 M vinylmagnesium bromide in THF (11 mL, 11.0 mmol) was added with the reaction temperature maintained below −60° C. The reaction mixture was stirred at −13 to −7° C. for 2 h and then warmed to room temperature over 30 min. The reaction was again cooled to −70° C., and a 2 M solution of hydrogen chloride in ether (22.5 ml, 45 mmol) was added. The reaction was then stored in a freezer at −10° C. overnight. After this time the mixture was evaporated under reduced pressure on a rotary evaporator, and the resulting residue partitioned between water (100 mL) and ether (100 mL). The ether extract was dried over sodium sulfate and evaporated under reduced pressure on a rotary evaporator to afford crude 113e (2.86 g, 118%) as a brown oil with approximately 75% purity (by NMR): 1H NMR (300 MHz, CDCl3) δ 7.45 (s, 1H), 3.89 (t, 2H, J=6.9 Hz), 3.30 (t, 2H, J=6.9 Hz), 2.75 (s, 2H), 2.59 (s, 2H), 1.24 (s, 6H)

Provenance & Evidence