Fig. 1
From: Cu(II)-Mediated direct 18F-dehydrofluorination of phosphine oxides in high molar activity
Screening of the oxidative metal salts for direct dehydrofluorination of phosphine oxides. a Stability of phosphine oxide 1a incubated under different pH conditions for 24 h. b Screening of metal salts, others: MnCl2, FeCl3·6H2O, FeSO4, Fe(OAc)3, Fe(OTf)3, NiCl2, Ni(acac)2, Cu(OMs)2, Cu powder, CuI, CuCl, ZnCl2, ZnBr2, Zn(NO3)2, ZnSO4, Zn(OAc)2, Zn(OTf)2, ZnO, AgTFA, Ag2SO4, AgOAc, AgOTf, Pd(OAc)2, PdCl2, Pd(acac)2, Pd(dba)2, PtCl2. c–e Optimization of Cu(OAc)2, CuCl2 and AgNO3-mediated fluorination reaction; The conditions of I: 1a (10 mg), metal salts (0.05–3 equiv.), acetone (0.5 mL), TBAF (2 equiv.); The conditions of II: 1a (10 mg), metal salts (2 equiv.), acetone (0.5 mL), KF or CsF or NaF or AgF (2 equiv.); The conditions of III: 1a (10 mg), metal salts (2 equiv.), CH3CN or THF or DMF or DMSO or CH3OH (0.5 mL), TBAF (2 equiv.); The conditions of IV: 1a (10 mg), metal salts (2 equiv.), acetone (0.5 mL), TBAF (2 equiv.), TEA or Py or DBU or AcOH (2 equiv.). f Comparison of fluorination efficiency mediated by Cu(OAc)2, CuCl2 and AgNO3 under optimal conditions. g The effects of water equivalent on conversions in Cu(OAc)2-mediated fluorination reaction. Reaction condition: 1a (10 mg), KF (2 equiv.), Cu(OAc)2 (2 equiv.), H2O (10–100 equiv.), DMSO (0.4 mL), 25 °C, 12 h. h The effects of water volume ratio on conversions in Cu(OAc)2-mediated fluorination reaction. Reaction condition: 1a (10 mg), KF (2 equiv.), Cu(OAc)2 (2 equiv.), H2O(v): DMSO(v) = 10: 90, 30: 70, 50: 50, 70: 30, 90: 10, 100: 0, 25 °C, 12 h