Methyl 2-Keto-L-gulonate is primarily used as an intermediate in the synthesis of ascorbic acid, also known as vitamin C. It plays a crucial role in the Reichstein process, a method for producing vitamin C on an industrial scale. The compound is involved in key steps where it undergoes chemical transformations to eventually form ascorbic acid. This application is vital for the pharmaceutical and food industries, where vitamin C is widely used as a dietary supplement and antioxidant. Additionally, it finds utility in research and development for studying biochemical pathways and optimizing synthetic routes for vitamin C production.