Dimethylformamide → 2-Chloro-3-(hydroxymethylidene)cyclohex-1-ene-1-carbaldehyde

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Reaction Steps

To a 500 mL flask were added DCM (40 mL) and DMF (40 mL). The mixture was cooled in an ice bath and then a solution of phosphorus oxychloride (37 mL) in DCM (35 mL) was added dropwise over approx. 1 h. To the still cool reaction mixture was added cyclohexanone (10 g, 0.10 mol) dropwise over 20 min. The mixture was stirred for a further 10 min and then was then heated at reflux for 3.5 h. After cooling to rt the mixture was poured onto 200 g of ice and then stirred until the ice melted. The mixture was left to stand during which time the aqueous phase became hot and caused some of the DCM to boil off. After the mixture cooled, crystals formed in the mixture. These were filtered off, washed with water (2×20 mL) and dried under vacuum to afford 32 (6.0 g, 34%).

Provenance & Evidence