in pentane byproducts: LiBr; (under Ar); alane-compd. is dissolved in n-pentane, LiCH(SiMe3)2 (ether-free) is added at 0°C, mixt. is warmed to room temp. and stirred for 1 h; LiBr is filtered off, solvent is distd. off at room temp. in vac., residue is recrystd. from n-pentane, elem. anal.;