in neat (no solvent) addn. of diborane to amine at liquid N2 temp., keeping at -111°C, -78°C and 0°C consecutively, stirring at 0°C for 4-6 h (vacuum line); cooling to -78°C, removal of B2H6 by distn.;

in tetrahydrofuran addn. of borane soln. to amine soln. at 0°C during 1 h, stirring for 1 h (N2); evapn. (vac.), drying (vac., overnight);