Sodium hydride → 3-(Benzhydrylideneamino)-8-oxabicyclo[3.2.1]octane-3-carboxylic Acid Ethyl Ester

Participants

Reaction Steps

To a suspension of sodium hydride (0.41 grams, 17.1 mmole) in N,N-dimethylformamide (50 mL) at 0° C. was added dropwise a solution of N-diphenylmethylene glycine ethyl ester (2.07 grams, 7.8 mmol) in N,N-dimethylformamide (50 mL). After stirring for 30 minutes at room temperature, a solution of cis-2,5-bis(hydroxymethyl)-tetrahydrofuran ditosylate (4.1 grams, 9.3 mmole) in N,N-dimethylformamide (50 mL) was added dropwise. The reaction mixture was gradually heated to 100° C. in an oil bath and stirred at this temperature overnight. The solvent was evaporated under vacuum and the reside was taken up in water and extracted twice with diethyl ether. The combined organic extracts were washed with brine, dried over magnesium sulfate and concentrated to a brown oil, from which the title compound (1.42 grams, 51%, a 3:1 mixture of exo/endo diastereomers) was isolated by chromatography on silica gel (20% ethyl acetate in hexane as eluant).

Provenance & Evidence