in tetrahydrofuran; hexane; pentane to the soln. of dilithium salt CH3BBr2/THF/pentane was added dropwise at -78°C, warmed to room temp., strirred for 2 h; evapd. in vac., fractional distn.; elem. anal.;

2,2,6,6-tetramethylpiperidine; n-C4H9Li in tetrahydrofuran tetramethylpiperidine in THF at -78°C was reacted with n-C4H9Li, stirring was continued at room temp. until the development of butane was ended, this soln. was added to the boron compd. in THF at -78°C;