Preparation method of 6,6-dimethyl-3-oxadicyclo[3.1.0]hexane-2,4-diketone

The invention provides a preparation method of 6,6-dimethyl-3-oxadicyclo[3.1.0]hexane-2,4-diketone. The method comprises the following steps of: oxidizing first ethyl chrysanthemate serving as a raw material in water serving as a solvent by adopting potassium permanganate and adding sulfuric acid for hydrolyzing to generate 3,3-dimethyl-1,2-cyclopropane dicarboxylic acid; and performing cyclization on the 3,3-dimethyl-1,2-cyclopropane dicarboxylic acid in a system consisting of acetic anhydride and sodium acetate to generate the 6,6-dimethyl-3-oxadicyclo[3.1.0]hexane-2,4-diketone. The invention has the advantages that: water is taken as a reaction solvent, so that increase in cost and environmental pollution caused by the use of a large quantity of organic solvents are avoided; and a large amount of sulfur dioxide gas produced by the use of sodium metabisulfite is eliminated, so that environmental pollution and treatment of three wastes are greatly reduced. The method has the advantages of environmentally-friendly reaction process, low environmental pollution, simple process and low cost, thereby being beneficial to industrial production.