1: C8H7O3(1-)*Li(1+); benzoic acid lithium salt With palladium diacetate in 1,4-dioxane T=100°C; 0.5 h; Inert atmosphereSealed tube; 2: ethyl N-mesitylsulfonyloxycarbamate in 1,4-dioxane T=100°C; 0.5 h; Inert atmosphereSealed tube; 3: With hydrogenchloride in 1,4-dioxane; water; ethyl acetate T=20°C; Inert atmosphere;