in hexane byproducts: LiF; under Ar or N2, 1 equiv. of Li-compd. was added in hexane to hexane soln. of B-compd. at -60 °C, stirring for 30 min, warming to room temp.; soln. was filtered, evapd. in vac., crystn. from a min. amt. of hexane between -25 and -30 °C, elem. anal.;