Synthesis method of key intermediate 4-fluoro-3-phenoxybenzaldehyde of insect repellant

The invention relates to the field of chemical synthesis of insect repellents, in particular to a synthetic method of a key intermediate 4-fluoro-3-phenoxybenzaldehyde of an insect repellant, which comprises the following steps: S1, synthesis of 3-bromo-4-fluorobenzaldehyde, S2, protection of aldehyde group, S3, substitution of methoxyl group, and S4, synthesis of a target product. The method has the effects of increasing the selectivity of products in the reaction process and reducing the generation of byproducts while increasing the production efficiency and shortening the reaction process. 本申请涉及驱虫剂化学合成的领域，尤其是涉及一种驱虫剂关键中间体4-氟-3-苯氧基苯甲醛的合成方法，其包括如下步骤：S1、3-溴-4-氟苯甲醛的合成，S2、醛基的保护，S3、甲氧基的取代，S4、目标产品的合成。本申请具有增加生产效率，缩短反应流程的同时，增加反应过程中产物的选择性，减少副产物的产生的效果。