Monoorganyldiisopropoxyboranes, RB (Oi-Pr) 2, react cleanly at-78" C with 1 equiv of organolithium compounds, R'Li, to form the corresponding complexes of the borinic acid esters, LiRR'B (Oi-Pr) p. Treatment of these complexes with an equivalent of anhydrous hydrogen chloride in ethyl ether liberates the borinic esters, RR'BO-i-Pr, and isopropyl alcohol, usually readily separated by distillation. Alternatively, treatment of the complexes ...