Sulfur Dioxide → HCID 54061678, compound

Participants

Reaction Steps

To a solution of thiophene-3-carboxaldehyde ethylene acetal (25.0 g, 160 mmol) in anhydrous THF (300 mL) under nitrogen at -70° C. was added n-butyllithium (2.5M, 76.9 mL, 192 mmol) over a 10 min period. The mixture was stirred for 40 min during which a white precipitate formed. Sulfur dioxide was passed over the mixture for about 10 min and the mixture was warmed to ambient temperature. The volatiles were evaporated and the residue was mixed with methylene chloride (400 mL), cooled to 0° C and N-chlorosuccinimide (29.9 g, 224 mmol) was added. The mixture was stirred for 2 h at ambient temperature and filtered through a bed of filter aid which was washed with ethyl acetate (400 mL). The filtrate was cooled on an ice bath and ethanolamin e (30 mL) was added. The reaction mixture was stirred for 1 h and a saturated solution of sodium bicarbonate (200 mL) added. The organic layer was separated, dried over magnesium sulfate, filtered and evaporated to dryness. Column chromatography (silica, gradient, 60% ethyl acetate in hexane) gave the desired product as an oil (35.72 g, 80%).

Provenance & Evidence