Isopropyl Acetate → (r)-5-Biphenyl-4-ylmethyl-3-[1-diisopropylamino-meth-(e)-ylidene]-2-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

N,N,N′,N′-tetraisopropylformamidinium tetrafluoroborate (2.13 g, prepared according to Example 11) is added to a 1 M solution of potassium-tert-butoxide in THF (5.69 ml). The resulting mixture is then stirred for 1 h at 50° C. (S)-2-Biphenyl-4-ylmethyl-5-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester (8-a, R1=Boc) (500 mg) is then added and the mixture stirred at 60° C. for 1 h. The mixture is then cooled to room temperature and diluted by addition of 10 ml isopropyl acetate. The mixture is then filtered through silica and concentrated in vacuo to afford (R)-5-biphenyl-4-ylmethyl-3-[1-diisopropylamino-meth-(E)-ylidene]-2-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester (7-a, R1=Boc, R6=iPr, R7=iPr). Spectroscopic data as for Example 19, Method 1.

Provenance & Evidence