107-02-8

13417-49-7

Acrolein [stabilized] (40 g, 713 mmol) was dissolved in a solvent mixture of dichloromethane (105 mL) and deionized water (2.3 mL) at room temperature and stirred to form a homogeneous mixture. Phosphoric acid (12.7 mL) was slowly added dropwise to the above mixture. The reaction system was heated to reflux and the reaction was continued overnight. Upon completion of the reaction, the reaction mixture was purified by reduced pressure distillation (110-150 °C, 20 mmHg) to afford the target product 5,6-dihydro-2-H pyran-3-carbaldehyde (12.6 g, 15.7% yield). Mass spectrometry result (m/z): [M + H]+ 113.1.