Benzcatechinborane → 2,2-difluoro-1(R)-(4-fluorophenyl)-2-(4-methylsulfanylphenoxy)ethanol

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,2-difluoro-1-(4-fluorophenyl)-2-(4-methylsulfanylphenoxy)ethanone (2.76 g, 8.84 mmol) and S-methyl-CS-oxazaborolidine in a mixture of DCM/Toluene (1/1, 40 ml) under nitrogen, at −70° C., a solution of catecholborane (1.27 g, 10.6 mmol) in DCM (2 ml) was slowly added. After stirring at −70° C. for 18 h, the reaction mixture was quenched by adding 4M solution of HCl in dioxane (3 ml). The heterogeneous mixture was stirred for 15 min at −70° C., then warmed to room temperature. Solvent was removed on a rotary evaporator and the resulting solution was diluted with hexanes (80 ml). Water (0.5 ml) was added and the mixture was stirred for 15 min. The solids were filtered and the filter cake was washed with hexanes. The filtrate was washed with 10% aqueous sodium metabisulfite (15 ml) and brine (15 ml). The organic phase was dried over sodium sulfate and the crude purified by flash chromatography, using EA/H (1/10) as eluent to give 2,2-difluoro-1(R)-(4-fluorophenyl)-2-(4-methylsulfanylphenoxy)ethanol (1.55 g, 56%) as a white solid.

Provenance & Evidence