2-(2-Fluoro-5-methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane acts as a reagent for the preparation of pyridinone and pyridazinone derivatives for the treatment of inflammatory diseases, diabetes, obesity, cancer, and AIDS, preparation of chroman, isochroman and tetrahydronaphthalene derivatives as antidiabetics.