1: 1.) 3A molecular sieves, 2.) BF3*Et2O / 1.) CH2Cl2, from -25 deg C to -20 deg C, 15 min, 2.) CH2Cl2, 30 min 2: 80.3 percent / NaOMe / methanol View Scheme

3 A molecular sieve; boron trifluoride diethyl etherate 1.) CH2Cl2, from -25 deg C to -20 deg C, 15 min, 2.) CH2Cl2, 30 min; Yield given. Multistep reaction;

acetic acid in diethyl ether; water 3 h; Ambient temperature;

1: 1.) dibutyltin oxide / 1.) benzene, toluene, reflux, overnight, 2.) benzene, toluene, RT, 2 d 2: pyridine 3: 96 percent / AcOH / H2O; diethyl ether / 3 h / Ambient temperature View Scheme