METHOD FOR PREPARING PINACOL BORANE (VARIANTS) Russian patent published in 2005 - IPC

FIELD: chemical technology.

SUBSTANCE: invention relates to technology for preparing organoboron compounds, in particular, pinacol borane (4,4,5,5-tetramethyl-1,3,2-dioxaborolane) representing a monofunctional hydride-borating agent for alkenes and alkynes and for Suzuki's cross-coupling reaction also. Method is carried out by interaction of pinacol (2,2,3,3-tetramethylethylene glycol, 2,3-dimethyl, 2,3-butanediol) with borane reagent in the presence of a solvent and the following isolation of the end product. Gaseous diborane is used as a borane reagent and the process is carried out in diethyl ether medium at range of temperatures 5-36°C, and the process is carried out in the mole ratio of reagents pinacol : diborane = 1:(0.45-0.55), respectively; or the method is carried out by interaction of pinacol with borane reagent and the following isolation of the end product wherein gaseous diborane is used as a borane reagent, and the process is carried out in pinacol melt at temperature ranges 40-80°C. The process is carried in the mole ratio of reagents pinacol : diborane = 1:(0.45-0.55), respectively. Method provides preparing pinacol borane with high yield 90-95% and high purity 99.5-99.8%. Method shows technological simplicity and economy profit in realization in the industrial scale.

EFFECT: improved preparing method.

3 cl, 4 ex