n-butyllithium in diethyl ether byproducts: LiCl; Ar-atmosphere; treatment of ligand with BuLi, ZrCl4 addn., stirring for 1 h; evapn., washing (pentane), extn. into CH2Cl2, filtration (Na2SO4), vol. reduction, recrystn. (layering CH2Cl2 soln. with hexane, -30°C);

in pentane byproducts: LiCl; Ar-atmosphere; stirring at room temp. overnight; decantation, extn. of residue into CH2Cl2, filtration off of LiCl, crystn. (-20°C, 1 week); elem. anal.;