Fig. 2: Preparation of P(V)–X reagents.

a Comparison of synthetic 1a by using different chlorination reagents. b The scope of different P(V)-sources in chlorination reaction. c The scope of different P(V)-sources in fluorination reaction. d ³¹P NMR monitored the reaction process of 1a. e Crystal structural model and physical property of 1a. f ³¹P NMR of 1c [TBA][PO₂F₂]. g Crystal structural model and physical property of 1c. Reaction conditions for 1a: [TBA][H₂PO₄] (3 mmol), TCT (76 mol%), FPyr (5 mol%), CH₃CN (2 mL), rt, 12 h. (The amount of TBAC is equal to the amount of phosphorus atom in the corresponding phosphate, refer to Supplementary Information S.2.1, Table S2). Reaction conditions for 1b: Guanidine phosphate (3 mmol), TCT (76 mol%), FPyr (5 mol%), CH₃CN (2 mL), rt, 12 h. Reaction conditions for 1c: [a] Direct fluorination. [TBA][H₂PO₄] (3 mmol), cyanuric fluoride (76 mol%), FPyr (5 mol%), CH₃CN (2 mL), rt, 12 h. [b] F–Cl exchange. [TBA][H₂PO₄] (3 mmol), TCT (76 mol%), TBAF 3H₂O (2.0 eq), CH₃CN (2 mL), rt, 12 h. (The amount of TBAF 3H₂O is equal to the amount of phosphorus atom in the corresponding phosphate, refer to Supplementary Information S.2.2, Table S6). [c] Reaction conditions for 1d: Na₃P₃O₉ (3 mmol), cyanuric fluoride (2 eq), TBAF 3H₂O (3.0 eq), FPyr (5 mol%), CH₃CN (2 mL), rt, 12 h.