4-Methoxybenzyl ether (PMB)

4-Methoxybenzyl ether (PMB) scheme

Protection :

  • Reagents
    Solvents
    Temperature
    Time
    Yield
  • Cl3C(=NH)OCH2(p-MeOPh) Sc(OTf)3
    PhMe
    0 °C
    2 h
    94 %
    intermediate structure
    Cl3C(=NH)OCH2(p-MeOPh), Sc(OTf)3
    PhMe
    0 °C, 2 h, 94%
    intermediate structure
  • Cl3C(=NH)OCH2(p-MeOPh) TfOH
    CH2Cl2
    0 °C
    3 h
    75 %
    intermediate structure
    Cl3C(=NH)OCH2(p-MeOPh), TfOH
    CH2Cl2
    0 °C, 3 h, 75%
    "99 % yield based on 76 % conversion."
    intermediate structure
  • Cl3C(=NH)OCH2(p-MeOPh) La(OTf)3
    THF
    RT
    3 h
    90 %
    intermediate structure
    Cl3C(=NH)OCH2(p-MeOPh), La(OTf)3
    THF
    RT, 3 h, 90%
    intermediate structure

Deprotection :

  • Reagents
    Solvents
    Temperature
    Time
    Yield
  • DDQ
    CH2Cl2 H2O
    RT
    60 min
    84-97 %
    intermediate structure
    DDQ
    CH2Cl2, H2O
    RT, 60 min, 84%
    intermediate structure
    intermediate structure
    DDQ
    CH2Cl2, H2O
    RT, 60 min, 97%
    intermediate structure
  • DDQ
    CH2Cl2 Buffer (pH = 7)
    RT
    60 min
    76 %
    intermediate structure
    DDQ
    CH2Cl2, Buffer (pH = 7)
    0 °C to RT, 60 min, 76%
    intermediate structure
  • DDQ
    CH2Cl2
    RT
    18 h
    90 %
    intermediate structure
    DDQ
    CH2Cl2
    RT, 18 h, 90%
    intermediate structure