METHOD OF SYNTHESIS OF DIISOPINOCAMPHEYLCHLOROBORANE IN REACTION MIXTURE, METHOD OF REDUCTION OF PROCHIRAL KETONE Russian patent published in 2000 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to the improved method of synthesis of diisopinocampheylchloroborane of the formula (I) in reaction mixture that involves interaction of sodium boron hydride and boron trichloride with α-pinene in inert solvent. Synthesized diisopinocampheylchloroborane can be used without isolation for reduction of prochiral ketones to corresponding alcohols of high optical purity. Invention proposes also method of reduction of prochiral ketone of the formula (II) to obtain optically active alcohol of the formula (III) where A is -CH=CH-S- or -CH=CH-CH=CH-; R¹ and R² are hydrogen or halogen atom; R³ is groups CO₂R⁶, COR⁶, C(R⁷)₂-OR⁸ where R⁶ is hydrogen atom or lower alkyl, R⁷ is lower alkyl and R⁸ is hydrogen atom or hydroxy-protective group. Alcohol of high optical purity is synthesized by interaction of sodium boron hydride and boron trichloride with α-pinene (optical purity of the latter is 70% or above) in inert organic solvent to obtain reaction mixture containing diisopinocampheylchloroborane followed by interaction of obtained mixture with prochiral ketone. The above indicated α-pinene is (1R)-(+)-α-pinene and solvent is polyalkoxylated ether. EFFECT: improved method of synthesis, high optical purity. 7 cl, 2 ex