Sulfuric Acid → 5,6,7,8-Tetrahydro-1H-benzo[b]cyclopenta[d]thiophen-3(2H)-one

Participants

Reaction Conditions

Reaction Steps

A 50-mL single-necked round-bottomed flask equipped with a magnetic stirrer was charged with 105b (800 mg, 3.51 mmol) and 98% sulfuric acid (8 mL). After stirring at 95° C. for 16 h, the reaction mixture was poured into ice (50 g), and the resulting suspension was extracted with ethyl acetate (3×50 mL). The organic extracts were combined, dried over sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash chromatography to afford 105c in 47% yield (320 mg) as an off-white solid: mp 75-76° C.; 1H NMR (500 MHz, CDCl3) δ 2.89 (m, 2H), 2.87-2.83 (m, 4H), 2.56 (t, 2H, J=6.5 Hz), 1.84 (m, 4H)

Provenance & Evidence