Imidazole → Tributylphosphine oxide

Participants

Reaction Steps

A solution of (5)-tert-butyl 2-((S)-1,2-bis(tert-butyldimethylsilyloxy)ethyl)aziridine-1-carboxylate (0.740 g, 1.7 mmol) and 1H-imidazole (0.35 g, 5.1 mmol) in 3 mL toluen was thoroughly degassed and treated with tributylphosphine (0.42 ml, 1.7 mmol). The reaction mixture was heated to reflux and allowed to stir for 3 hours. NaH (60% dispersion in mineral oil) (0.069 g, 2.9 mmol) was added and the reaction mixture was allowed to stir at 110° C. overnight. The reaction mixture was quenched with saturated NH4Cl solution and diluted with EtOAc. The reaction mixture was washed with water then brine. The organics were dried over MgSO4 and concentrated in vacuo. Purification of the crude residue by column chromatography gave tert-butyl (2S,3S)-3,4-bis(tert-butyldimethylsilyloxy)-1-(1H-imidazol-1-yl)butan-2-ylcarbamate with tributylphosphine oxide as the major impurity. This material was used without further purification.

Provenance & Evidence