Reaction SMILES: C(O[P:4]([C:9]1[CH:14]=[CH:13][C:12]([N+:15]([O-:17])=[O:16])=[CH:11][CH:10]=1)(=[O:8])OCC)C.S(Cl)(Cl)=O.[N+]([C:25]1C=CC(P(Cl)(Cl)=O)=C[CH:26]=1)([O-])=O.[CH:35]([Mg]Br)=[CH2:36]>CN(C)C=O.O1CCCC1>[CH:25]([P:4]([CH:35]=[CH2:36])([C:9]1[CH:10]=[CH:11][C:12]([N+:15]([O-:17])=[O:16])=[CH:13][CH:14]=1)=[O:8])=[CH2:26]
Reactant: O=[N+]([O-])c1ccc(P(=O)(Cl)Cl)cc1
Reactant: CCOP(=O)(OCC)c1ccc([N+](=O)[O-])cc1
Reactant: C=C[Mg]Br
Solvent: O=S(Cl)Cl
Solvent: CN(C)C=O
Solvent: C1CCOC1
Product: C=CP(=O)(C=C)c1ccc([N+](=O)[O-])cc1
Temperature: 25 °C
Reaction time: 1 h

Procedure:
A mixture of 1-bromo-4-nitrobenzene (400 mg, 2.00 mmol), tetrakis(triphenylphosphine)palladium(0) (120 mg, 0.20 mmol) and cesium carbonate (734 mg, 2.2 mmol) in a 30 mL microwave vial was purged and backfilled with nitrogen. Tetrahydrofuran (20 mL) was added followed by diethyl phosphite (0.360 mL, 2.8 mmol). The mixture was vortexed, then microwaved for 45 minutes at 120° C. Reaction was repeated three times to achieve total scale then the combined reaction mixtures were purified via chromatography (120 g silica gel 5%→75% ethyl acetate in hexane). (4-Nitro-phenyl)-phosphonic acid diethyl ester isolated as a light yellow oil (969 mg, 47%). 1H NMR (400 MHz, (D3C)2SO, δ, ppm): 8.35 (d, J=8.0 Hz, 2H), 7.16 (s, 1H), 5.93 (s, 2H), 3.40 (s, 4H), 2.36 (s, 4H), 2.20 (s, 3H), 8.05-7.95 (m, 2H), 4.09 (m, 4H), 1.25 (t, J=13.8, 7.4 Hz, 6H). 411b) To a solution of (4-Nitro-phenyl)-phosphonic acid diethyl ester (2.31 g, 8.91 mmol) in N,N-dimethylformamide (1 mL) was added thionyl chloride (3.25 mL, 44.6 mmol). The reaction mixture was heated to reflux for 2 hours, cooled to room temperature and concentrated in vacuo. The residue was azeotroped with carbon tetrachloride several times to remove excess thionyl chloride. 4-Nitrophenylphosphonic dichloride was carried on crude to the next reaction. 411c) To a solution of 4-Nitrophenylphosphonic dichloride (2.14 g, 8.91 mmol) in tetrahydrofuran at −78° C. was added vinylmagnesium bromide (2.34 g, 17.8 mmol). The solution was stirred at −78° C. for one hour then quenched by the addition of ammonium chloride solution. The mixture was extracted with dichloromethane. The combined organic layers were dried and concentrated. 4-(Divinyl-phosphinoyl)nitro benzene was isolated as a brown-yellow oil (1.69 g, 85%). MS=224 (MH)+. 411d) A mixture of 4-(Divinyl-phosphinoyl)nitro benzene (1.69 g, 7.56 mmol), water (10 mL), 1.0 M of sodium hydroxide in water (7.56 mL, 7.56 mmol) and tetrahydrofuran (10.0 mL, 123 mmol) was treated with ethylamine hydrochloride (678 mg, 8.32 mmol) then heated at 105° C. for one hour. An additional portion of ethylamine hydrochloride was added and the reaction was heated for an additional 2 hours. The reaction was cooled, poured into saturated sodium bicarbonate solution and extracted with dichloromethane. The aqueous layer was treated with solid sodium chloride and extracted and additional 4 times to isolate all the product. The combined organic layers were dried over magnesium sulfate, filtered and evaporated. The residue was purified via chromatography (40 g silica gel and 0%→10% methanol in dichloromethane). 1-Ethyl-4-(4-nitro-phenyl)-perhydro-1,4-azaphosphorine 4-oxide was isolated as yellow oil (300 mg, 10%). 1H NMR (400 MHz, (D3C)2SO, δ, ppm): 8.34 (d, J=8.4 Hz, 2H), 8.11 (t, J=18.46, 9.15 Hz, 2H), 2.91-2.75 (m, 4H), 2.51-2.46 (m, 2H), 2.29 (m, 2H), 1.96 (m, 2H), 1.01 (t, J=14.4, 7.5 Hz, 3H). MS=269 (MH)+. 411e) 1-Ethyl-4-(4-nitro-phenyl)-perhydro-1,4-azaphosphorine 4-oxide (269.80 mg, 1.0058 mmol) dissolved in Ethanol (50 mL) and treated with palladium on carbon 10% (90:10, carbon black:Palladium, 30 mg, 2 mmol), 2.5 M of hydrogen chloride in ethanol (1.21 mL, 3.02 mmol) and 50 PSI of hydrogen gas. The mixture was shaken on a Parr apparatus for 5 hours. The mixture was degassed and backflushed with nitrogen. The mixture was filtered through a plug of diatomaceous earth and washed with ethanol. The filtrate was evaporated. 4-(1-ethyl-4-oxido-1,4-azaphosphinan-4-yl)aniline hydrochloride was isolated (401 mg, 145%). MS=238 (MH)+. 411f) N-[4-(1-ethyl-4-oxido-1,4-azaphosphinan-4-yl)phenyl]-8-[4-(methylsulfonyl)phenyl][1,2,4]triazolo[1,5-a]pyridin-2-amine was prepared from 2-Chloro-8-(4-methanesulfonyl-phenyl)-[1,2,4]triazolo[1,5-a]pyridine (133 mg, 0.434 mmol) and 4-(1-ethyl-4-oxido-1,4-azaphosphinan-4-yl)aniline hydrochloride (131.01 mg, 0.47689 mmol) in a manner analogous to Example 2d. Product isolated as an off-white solid (31.56 mg, 14%). 1H NMR (400 MHz, CDCl3, δ, ppm): 8.54 (d, J=8.3 Hz, 1H), 8.23 (d, J=8.0 Hz, 2H), 8.01 (d, J=8.0 Hz, 2H), 7.80-7.67 (m, 5H), 7.08 (t, J=13.6, 7.0 Hz, 1H), 3.13-2.90 (m, 7H), 2.61 (m, 2H), 2.27-2.02 (m, 4H), 1.13 (t, J=13.6, 6.4 Hz, 3H). MS=510 (MH)+.