(2R,3S)-2-methyl-3-phenyloxirane

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of cis-β-methyl styrene (0.059 g, 0.5 mmol) and ketone IVd (0.026 g, 0.075 mmol) in DME-DMM (3:1, v/v) (7.5 mL) were added buffer (0.2 M K2CO3—AcOH in 4×10−4 M aqueous EDTA, buffer pH=8.0) (5 mL) and Bu4NHSO4 (0.0075 g, 0.02 mmol) with stirring. After the mixture was cooled to about −10° C. (bath temperature) via a NaCl-ice bath, a solution of Oxone® (0.212 M in 4×10−4 M aqueous EDTA, 4.2 mL) (0.548 g, 0.89 mmol) and K2CO3 (0.479 M in 4×10−4 M aqueous EDTA, 4.2 mL) (0.278 g, 2.01 mmol) were added dropwise separately over a period of 3.5 h via a syringe pump. The reaction was then quenched with the addition of pentane and extracted with pentane. The combined organic layers were washed with brine, dried (Na2SO4), filtered, concentrated, and purified by flash chromatography (the silica gel was buffered with 1% Et3N in pentane; pentane-ether (1/0 to 50/1 was used as eluent) to give cis-β-methylstyrene oxide as a colorless liquid (0.58 g, 87% yield, 91% ee). The reaction was then quenched with the addition of pentane extracted with pentane The combined organic layers were washed with brine dried (Na2SO4) filtered concentrated purified by flash chromatography (the silica gel

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of cis-β-methyl styrene (0.059 g, 0.5 mmol) and ketone IVd (0.026 g, 0.075 mmol) in DME-DMM (3:1, v/v) (7.5 mL) were added buffer (0.2 M K2CO3—AcOH in 4×10−4 M aqueous EDTA, buffer pH=8.0) (5 mL) and Bu4NHSO4 (0.0075 g, 0.02 mmol) with stirring. After the mixture was cooled to about −10° C. (bath temperature) via a NaCl-ice bath, a solution of Oxone® (0.212 M in 4×10−4 M aqueous EDTA, 4.2 mL) (0.548 g, 0.89 mmol) and K2CO3 (0.479 M in 4×10−4 M aqueous EDTA, 4.2 mL) (0.278 g, 2.01 mmol) were added dropwise separately over a period of 3.5 h via a syringe pump. The reaction was then quenched with the addition of pentane and extracted with pentane. The combined organic layers were washed with brine, dried (Na2SO4), filtered, concentrated, and purified by flash chromatography (the silica gel was buffered with 1% Et3N in pentane; pentane-ether (1/0 to 50/1 was used as eluent) to give cis-β-methylstyrene oxide as a colorless liquid (0.58 g, 87% yield, 91% ee). The reaction was then quenched with the addition of pentane extracted with pentane The combined organic layers were washed with brine dried (Na2SO4) filtered concentrated purified by flash chromatography (the silica gel