Propanal → 4-But-3-enyl-5-ethyl-2,2-diphenyl-oxazolidine-4-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

While under a nitrogen atmosphere, a stirred solution of 2-(benzhydrylidene-amino)-hex-5-enoic acid tert-butyl ester (350 mg, 1 mmol) in THF (5 mL, 0.2 M) was cooled to −78° C. and carefully treated with sodium bis(trimethylsilyl)amide (2 mL, 1 M, 2 equiv). After stirring 30 min, diethyl aluminum chloride (2.4 mL, 1 M, 2.4 equiv) was added and the reaction mixture was stirred an additional 30 min. Propionaldehyde (94 μl, 1.25 mmol, 1.25 eq) was added to the solution and the cooling bath was removed. After stirring overnight the reaction mixture was cooled to 0° C. and quenched with saturated NH4Cl. The resulting solution was diluted with ethyl acetate and washed successively with water and saturated potassium sodium tartrate, dried over MgSO4, filtered and concentrated. Purification by MPLC (1-40% ethyl acetate in heptane) gave 4-but-3-enyl-5-ethyl-2,2-diphenyl-oxazolidine-4-carboxylic acid tert-butyl ester (349 mg, 0.86 mmol, 86%).

Provenance & Evidence