tri-isopropoxy-borane in tetrahydrofuran; n-heptane; ethylbenzene 2.41667 h; Cooling with ice;

hydrogenchloride; lithium diisopropyl amide in tetrahydrofuran; n-heptane; ethylbenzene addn. of boron compd. to a soln. of indole deriv. in THF, cooling to 0°C, dropwise addn. of Li salt in THF/heptane/ethylbenzene over 1 h,stirring for 30 min, addn. of 2 M HCl, stirring at room temp. for 10 mi n; sepn., extn. aq. layer with ethyl acetate, drying org layer with Na2SO4,filtration, evapn. in vac.;

1.1: 93 percent / (dimethylamino)pyridine / tetrahydrofuran / 20 °C 2.1: triisopropyl borate / tetrahydrofuran / 0 °C 2.2: 99 percent / lithium diisopropylamide / heptane; tetrahydrofuran; ethylbenzene / 0.5 h / 0 °C View Scheme

1.1: 93 percent / (dimethylamino)pyridine / tetrahydrofuran / 20 °C 2.1: triisopropyl borate / tetrahydrofuran / 0 °C 2.2: 99 percent / lithium diisopropylamide / heptane; tetrahydrofuran; ethylbenzene / 0.5 h / 0 °C View Scheme