General method for reaction compound 1 with phenyl phosphorus halides: Synthesis of 2-aryl-3-benzoyl-4-hydroxy-2H-1,2-benzoxaphosphinines 2-4. P,P-Dichlorophenylphosphine, phenyl phosphonic dichloride and phenyl phosphorodichloridate (5 mmol) was added individually to a solution of compound 1 (5 mmol, 1.20 g) in dry toluene (30 mL) in the presence of triethylamine (10 mmol, 1.4 mL) as a base, under stirring for 30 minutes at 10 o C then heated under reflux for 8-12 hours. The formed solids were filtered off, washed with water and crystallized from diluted EtOH. 3-Benzoyl-4-hydroxy-2-phenyl-2H-1,2-benzoxaphosphinine (2). Orange solid in 59% yield;