Synthesis of 3-OXO-3-Phenyl-2,2,5-Trimethyl-1,3-Oxaphosphorinanes and their tetrafluoroborate salts - López Cortina, Susana; Elizondo Martínez, Perla; Pérez Rodríguez, Nancy; Hernández Fernández, Eugenio; Fernández Zertuche, Mario