1: pentane; benzene 2: hexane View Scheme

boron tribromide in pentane T=-40°C; 3 h;

in pentane react. BBr3 and pyrrolidine in pentane at -40°C; react. mixt. was filtered, product was distilled;

in benzene presence of C2H5MgBr;

boron tribromide in pentane T=-40°C; 3 h;

in pentane all manipulations under N2; soln. of BBr3 added to stirred soln. of B compd. at -50- -40°C over period of 20 min, after 3 h allowed to warm to room temp.; solvent removed in vac., distd. in vac., elem. anal.;