反应详情

Para-formaldehyde (1 g) and zinc chloride (catalytic amount) were mixed together at 0° C. 2,2-Di-n-propylacetyl chloride (30 mole, 4.88 g) was added dropwise over 1 hour. The reaction was warmed to ambient temperature, then was heated to 50-55° C. for 6 hours. The reaction mixture continued stirring at room temperature for 16 hours. The reaction mixture was taken up with methylene chloride (5 mL) and flash chromatographed on 150 g silica gel. Elution with 1 to 5% ethyl acetate/hexane gave 3.3 g (58%) of the desired product.

1. temperaturewas heated to 50-55° C. for 6 hours
2. customchromatographed on 150 g silica gel
3. washElution with 1 to 5% ethyl acetate/hexane