Benzcatechinborane → (S)-ethyl 2-(6-bromo-3-methyl-1-(trifluoromethylsulfonyloxy)naphthalen-2-yl)-2-hydroxyacetate

Participants

Reaction Steps

To a solution of ethyl 2-(6-bromo-3-methyl-1-(trifluoromethylsulfonyloxy)naphthalen-2-yl)-2-oxoacetate (2 g, 4.26 mmol) and (R)-2-methyl-CBS-oxazaborolidine (0.236 g, 0.85 mmol) in anhydrous toluene at −40° C. was added a solution of catecholborane (0.615 mL, 5.79 mmol) in toluene (10 mL) over 40 minutes. The reaction mixture was stirred for 1 hour and quenched with sodium carbonate solution, diluted with ethyl acetate and stirred vigorously for 20 minutes at −20° C., then at room temperature for 45 minutes. The aqueous layer was removed and the organic layer was washed with sodium carbonate solution (4×), saturated ammonium chloride solution, dried (MgSO4), filtered, concentrated and purified by flash column chromatography (silica gel, 0 to 20% ethyl acetate/hexanes) to give the desired compound.

Provenance & Evidence