Acetic Acid → (R)-3-(3-methoxybenzyl)-4-oxocyclopent-2-enyl acetate

Participants

Reaction Steps

4-Hydroxy-2-(3-methoxybenzyl)cyclopent-2-enone (9 g, 41.26 mmol) was dissolved in isobutyl methyl ketone (90 mL), and vinyl acetate (8.4 g, 97.57 mmol) and Lipase derived from Pseudomonas cepacia (0.9 g) were added to the solution, and the mixture was stirred at room temperature overnight. The reaction mixture was filtered to remove the Lipase and the filtrate was evaporated. The resulting residue was dissolved in PhCH3 (150 ml), and triphenylphosphine (6.5 g; 24.78 mmol) and AcOH (1.61 g, 26.81 mmol) were added to the solution. Then diisopropylazodicarboxylate (5 g, 24.72 mmol) was added to the mixture at 5° C. After the reaction was completed, the reaction mixture was filtered to remove the precipitate and the filtrate was evaporated. The residue was purified by chromatography on a silica gel column using hexane-EtOAc as eluent to give the (R)-3-(3-methoxybenzyl)-4-oxocyclopent-2-enyl acetate as yellow oil: 10 g (yield: 93%, 95% ee by HPLC using a chiral column)

Provenance & Evidence