A novel and efficient alkylation procedure of B--H-1,3,2-oxazaborolidines derived from ephedrine and norephedrine has been established. Representative B-butyl- and B-methyl-1,3,2-oxazaborolidines were prepared in good yield and excellent purity by one pot treatment of the parent boraheterocyclic compound with the corresponding organolithium reagent and subsequent hydrolysis of the cyclic borohydride with anhydrous ammonium chloride.