Provided are novel cyclic phosphinate derivatives and a method of preparing the same, and more particularly, cyclic phosphinate derivatives including benzoxaphosphole oxide derivatives and benzoxaphosphorin oxide derivatives, and a method of preparing the same. The cyclic phosphinate derivative according to the present invention may have pharmacological and physiological activities, be used as the basic skeleton of the natural material, and be used in development of a new drug, and synthesis of various medicines. In addition, with the method of preparing a cyclic phosphinate derivative according to the present invention, various cyclic phosphinate derivatives may be prepared with high yield through a simple synthetic process by performing an intramolecular carbon-oxygen coupling reaction on the phosphinic acid derivative in the presence of a palladium (Pd) catalyst, an oxidant, and a base.