n-butyllithium in diethyl ether; hexane byproducts: butane, LiCl; (Ar); addn. of a soln. of lithium compd. in hexane to a soln. of ligand in Et2O, stirring for 8 h at room temp., cooling to -78°C, addn. of ZrCl4, warming to room temp. within 6 h, stirring for 6 h; evapn., suspn. in CH2Cl2, filtration through Na2SO4, evapn., washing with pentane and Et2O, crystn. (CH2Cl2, -28°C);