Peroxides as Switches of Dialkyl H-Phosphonate: Two Mild and Metal-Free Methods for Preparation of 2-Acylbenzothiazoles and Dialkyl Benzothiazol-2-ylphosphonates

Two mild and metal-free methods for the preparation of two kinds of important benzothiazole derivatives, 2-acylbenzothiazoles and dialkyl benzothiazol-2-ylphosphonates, respectively, were developed. The diallcyl H-phosphonate (RO)(2)P(O)H exists in equilibrium with its tautomer dialkyl phosphite (RO)(2)POH. TBHP triggered alpha-carbon-centered phosphite radical formation, whereas DTBP triggered phosphorus-centered phosphonate radical formation. The two types of radicals led respectively to two different reaction processes, the direct C-2-acylation of benzothiazoles and C-2-phosphonation of benzothiazoles.