Lithium diisopropylamide → 2-(4-Benzyloxy-2,6-dimethylphenyl)-3-methoxy-5-[1-(tetrahydropyran-4-yl)-methylidene]cyclopent-2-enone

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-(4-benzyloxy-2,6-dimethylphenyl)-3-methoxycyclopent-2-enone (1.93 g, 6.0 mmol) in THF (25 ml) under a nitrogen atmosphere at −78° C. is added a solution of lithium diisopropylamide (3.33 ml, 6.0 mmol, 1.8M in tetrahydrofuran) dropwise over 1 minute. The reaction is then stirred at −78° C. for 30 minutes followed by the addition of 4-tetrahydropyran carbaldehyde (0.684 g, 6.0 mmol) in one portion. After a further 5 minutes at −78° C. the reaction is allowed to warm to ambient temperature and stir for an additional 1 hour. Potassium tert-butoxide (1.10 g, 9.82 mmol) is then added in one portion and the reaction mixture is allowed to stir for a further 1 hour at room temperature. After quenching with saturated ammonium chloride solution (50 ml) the crude product is extracted into ethyl acetate (50 ml), and the organic phase is dried over anhydrous magnesium sulfate and concentrated in vacuo. Purification by flash column chromatography affords 2-(4-benzyloxy-2,6-dimethylphenyl)-3-methoxy-5-[1-(tetrahydropyran-4-yl)-methylidene]cyclopent-2-enone as a white solid.

Provenance & Evidence