Method for synthesizing fludioxonil intermediate 2, 2-difluoro-1, 3-benzodioxolane-4-formaldehyde

The invention relates to a method for synthesizing a fludioxonil intermediate 2, 2-difluoro-1, 3-benzodioxolane-4-formaldehyde, which comprises the following steps of: reacting 2, 3-dihydroxy benzaldehyde and thiophosgene which are used as raw materials under the action of alkali to generate 2-thioketone-1, 3-benzodioxolane-4-formaldehyde, and reacting under the action of a catalyst to generate 2-thioketone-1, 3-benzodioxolane-4-formaldehyde, thereby obtaining the fludioxonil intermediate 2, 2-difluoro-1, 3-benzodioxolane-4-formaldehyde. The preparation method comprises the following steps: reacting 2, 2-difluoro-1, 3-benzodioxolane-4-formaldehyde with a fluorinating reagent bis (2-methoxyethyl) amino sulfur trifluoride (BAST) to synthesize 2, 2-difluoro-1, 3-benzodioxolane-4-formaldehyde, and further synthesizing 2, 2-difluoro-1, 3-benzodioxolane-4-formaldehyde. The method has the advantages of few steps, simple operation, easily available raw materials and high yield, is suitable for industrial large-scale