Used as a key reagent in the Horner-Wadsworth-Emmons (HWE) reaction for the stereoselective synthesis of (E)-α,β-unsaturated compounds from aldehydes and ketones. This phosphonate serves as an intermediate in organic synthesis, enabling the construction of carbon-carbon double bonds in complex molecules. It is commonly employed in pharmaceutical research for developing kinase inhibitors and therapeutic agents targeting neurological and inflammatory disorders. Additionally, it is utilized in agrochemical synthesis to create novel pesticides with enhanced efficacy. The unique isobenzofuranone structure facilitates subsequent modifications, making it highly valuable in medicinal chemistry.