2-Cyclopenten-1-one → (R)-3-(4-Bromophenyl)cyclopentan-1-one

Participants

Reaction Steps

To a mixture of 7.2 g (35.8 mmol) of 4-bromophenylboronic acid, 186 mg (0.72 mmol) of acetylacetonatobis(ethylene)rhodium (I) and 446 mg (0.71 mmol) of (R)-2,2′-bis(diphenylphosphino)-1,1′binaphthyl (BINAP) in 60 mL of dioxane and 6 mL of H2O under nitrogen was added 1.0 mL (11.9 mmol) of 2-cyclopenten-1-one. After refluxing for 5.5 h, the reaction was concentrated. The residue was partitioned between 300 mL of EtOAc and 300 mL of 1 N NaHCO3. After separating phases, the organic layer was washed with 300 mL of brine, dried over Na2SO4 and concentrated. The residue was purified on a 40M Biotage column using 9:1 v/v hexane/EtOAc as the eluant to afford 1.90 g of the title compound as a white solid: 1H NMR δ 1.97 (m, 1H), 2.29-2.37 (m, 2H), 2.43-2.52 (m, 2H), 2.69 (m, 1H), 3.40 (m, 1H), 7.16 (d, J=8.5, 2H), 7.49 (d, J=8.5, 2H).

Provenance & Evidence