Synthesis Of ?-Indole Phosphonate Ester Based On CDC Reaction

Organic phosphorus chemistry has occupied an important position in the entire field of chemistry with its rapid development. Organophosphorus compounds are widely used in agriculture, industry, medicine and materials, as an important class of compounds that has been widely concerned for containing C-P bonds. For its biological activity and used as important intermediates in pesticide and medicine fields, synthetise of Aryl phosphate is of great significance.After Hirao group first successfully introducing phosphonate groups on the aryl or vinyl structure by using aryl iodides, bromides and H-phosphate under [Pd(PPh3)]/Et3 N catalytic system, a series of methods for the synthesis of aryl phosphonates were reported by using transition metal catalyst coupled reaction, such as Aryl sulfonates, Arenediazonium tetrafluoroborates, Arylboronic acids and phosphorus reagent were used as substrates.In recent years, cross dehydrogenative coupling(CDC) reaction has been widely used in the construction of the C-C and C-X bonds. Compared with the traditional coupling reaction, CDC reaction does not need to prefunctionalized substrate. The cleavage of C-H bond and the formation of C-P bond at the same time by using transition metal catalyst. CDC reaction has a wide applicability for substrate and recommended by its convenient, efficient, green and environmental protection.Based on the nitrogen atom containing a substituted group of indole and H-phosphite as substrates, we successfully synthesised a series of indolylphosphonate by using CDC reaction. After screening and optimizing of catalyst, oxidant, solvent and reaction temperature, the method for synthesising indolylphosphonate under Ag NO3/K2S2O8 system was determined.Reaction conditions: solvent DMF/H2O(5:1), catalyst Ag NO3(0.1 eq), oxidant K2S2O8(2 eq), under 70 (?) for 2 h. We acquire target material in moderate yield. The reaction site and final structure was determined by the analysis of X-diffraction on the crystal structure of compound 2e. All target compounds in this paper were identified by 1H NMR, 13 C NMR, 31 P NMR, IR, MS and HRMS.