Potassium sodium tartarate → (E)-(R)-5-(tert-Butyldimethylsilyloxy)-4-methylpent-2-ene

Participants

Reaction Steps

Diisobutylaluminum hydride (1 M solution in hexane, 86 mL) was added to a solution of (S)-3-(tert-butyldimethylsilyloxy)-2-methylpropionic acid methyl ester (20 g, 86.1 mmol) in dichloromethane (400 mL) at −78° C., and the mixture was stirred at the same temperature for two hours. A saturated potassium sodium tartrate solution was added to the reaction mixture which was then stirred while heating to room temperature. The organic layer was separated, and then the aqueous layer was extracted with ethyl acetate. The organic layers were combined, dried over magnesium sulfate, and filtered, and the solvent was evaporated under reduced pressure. The residue was dissolved in dichloromethane (200 mL). Triphenylphosphonylideneacetic acid methyl ester (32 g, 94.7 mmol) was added under ice-cooling, and the mixture was stirred at room temperature overnight. The reaction solution was filtered, and then the solvent was evaporated under reduced pressure. Hexane was added to the resulting residue, and the insoluble material was removed by filtration. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=4:1) to give 25 g (quantitative) of the title compound as a colorless oil.

Provenance & Evidence