boron trifluoride diethyl etherate in tetrahydrofuran 48 h; Heating;

1: 56 percent / 1)Borane-methyl sulfide complex 2)aq.NaOH,hydrogen peroxide / tetrahydrofuran / 1)reflux 2h 2)room temp. overnight 3)reflux 5h 2: 59 percent / Boron trifluoride ether complex / tetrahydrofuran / 48 h / Heating View Scheme