in diethyl ether Stirring a cooled soln. (-70°C) of Me2BOEt and 1,8-dilithionaphthalene in Et2O, allowing to warm to 10°C, recooling (-70°C), and then adding BF3*Et2O and allowing to warm to 10°C.; Removal of volatiles (vac.), extn. of residue (ambient temp., Ar) with hexane, cooling of ext. (-70°C) and filtn. (Ar). Concn. of filtrate gives resulting oil (68percent) contaminated with small amt. of hydrocarbon impurities. Purifn. by vac. distn.;