methanesulfonic acid in tetrahydrofuran byproducts: (CH3)3B; dropwise addn. of CH3Li (1 equiv.) to soln. of C6H11B(OCH3)2 (2.5 mmol) in THF at -78°C via syringe; stirring at -78°C for 3 h; addn. of CH3SO3H at -78/25°C; warming slowly to room temp.; stirring at room temp.;; not isolated; product distribution (depending on temp. at which the acid is added) is determined by 11B-NMR;;