3,4-Dihydro-2H-pyran-5-ylboronic Acid Pinacol Ester is derived from Dihydro-2H-pyran-3(4H)-one (D453408), which is a general chemical reagent used in the synthesis of pharmaceuticals such as the preparation of tetrahydropyran-2-yl chromans, a highly selective beta-site amyloid precursor protein cleaving enzyme 1 (BACE) inhibitor.