• 1188
  • A+



A 20 ml of scintillation vial equipped with a magnetic stirrer wascharged with a solution of MeSO2NclNa(455mg, 3.0mmol, 3.0 equiv) in 7.5 ml ofwater, 7.5 ml of nPrOH, and (DHQD)2PHAL (40mg, 0.05mmol, 0.05 equiv). To theresulting stirred clear colorless solution was then added isopropyltrans-cinnmate (190mg, 1.0mmol), followed by K2Os2(OH)4(14.8mg, 0.04mmol, 0.04equiv). The reaction mixture turned green after several minutes and was stirredfor 3.5 hours, by which time the reaction mixture has turned a clear, lightyellow. The presumed significance of the color change as an indication of theend point of the reaction was confirmed by a TLC analysis, which revealed thatno olefin remained. (With dimethyl fumarate the green color was only observedwhen an additional 0.5 equiv tert-butyl hypochlorite was added. For thefumarate case, the extra tert-butyl hypochlorite also resulted in much betteree and yield.) the reaction was then quenched by addition of 10 ml of saturatedNa2S3( This reductive quench is exothermic and cooling is needed forlarge-scales). The added salt caused phase separation. The aqueous phase wasseparated and extracted with ethyl acetate(3X30ml). The combined organic phaseswere dried over Mg2SO4 and concentrated to afford the crude product(impuritieswere mainly methanesulfonamide and diol). For an accurate yield the crudeproduct was purified by flash chromatography( SiO2, 30% ethyl acetate/hexane)and afforded 195mg(65%, >99%ee) crystalline aminohydroxylation product.



2016-07-18 nf