Sodium Hydroxide → tert-butyl (1R,2R)-1-(2-bromopyridin-4-yl)-2-hydroxy-2-phenylethylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl carbamate (2.96 g, 25.3 mmol) in propanol (30 mL) was added sodium hydroxide (0.994 g, 24.86 mmol) in water (54 mL) followed by tert-butyl hypochlorite (2.81 mL, 24.86 mmol). After 5 min, the solution was cooled to 0° C. and treated with a solution of (DHQD)2PHAL (0.317 g, 0.407 mmol) in propanol (30 mL). To this was added a solution of (E)-2-bromo-4-styrylpyridine (2.12 g, 8.15 mmol) in propanol (51 mL). To this was added potassium osmate dihydrate (0.120 g, 0.326 mmol) as a solid in one portion. The reaction was allowed to gradually warm in the glass dewar overnight. In the morning, the bath was still cool (5° C.). The reaction was quenched by addition of sodiumthiosulfate (2.7 g) in water (30 mL). The cooling bath was removed and the reaction stirred for 30 min. The reaction was poured into water (ca. 400 mL) and extracted with diethyl ether (2×). The combined organics were washed with water (2×), then brine, dried over magnesium sulfate, and concentrated. The resulting residue was concentrated from toluene (3×) to help remove an unknown impurity. The resulting residue was purified by column chromatography (25%-->40% EtOAc/Hex) to give 1.85 g (58%) as a mixture of regioisomers which was used without further purification. Mass spec.: 393.15 (MH)+.

Provenance & Evidence