in pentane byproducts: ethane; to cooled soln. of Et3Al added dropwise soln. of Et2BOH with vigorous stirring at 0-20°C, left to reach room temp.; distd. off in vac.;

in benzene byproducts: isobutane; ca. 20percent (by weight) C6H6 soln. of Et2BOH added dropwise with vigorous stirring to C6H6 soln. of i-Bu3Al at 20°C; volatiles distd. off in vac.;