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

Participants

Reaction Conditions

Reaction Steps

4-Bromophenylboronic acid (4 g, 19.92 mmol), Rh(acac)(C2H4)2 (acetylacetonatobis(ethylene)Rhodium (I); 103 mg, 0.4 mmol) and (R)-BINAP (249 mg, 0.4 mmol) were placed in a 100 mL 3-necked round bottomed flask and 1,4-dioxane (40 mL) was added. The reaction vessel was degassed several times before putting under a nitrogen atmosphere. Water (4 mL) was added followed by cyclopent-2-en-1-one (1.185 mL, 14.14 mmol). The reaction mixture was then heated at 100° C. overnight before cooling and washing with saturated aqueous sodium hydrogen carbonate solution (50 mL). The mixture was extracted with EtOAc (2×100 mL) and the organics dried then purified by chromatography eluting with 0-40% EtOAc/isohexane) to give the title compound (1.62 g, 48%) as an oil that crystallised upon standing; 1H NMR δ1.86-1.93 (1H, m), 2.23-2.36 (3H, m), 2.53-2.57 (1H, m), 3.34-3.43 (1H, m), 7.29-7.32 (2H, m), 7.50-7.53 (2H, m); αD=+20° (MeOH, c=1, L=1)

Provenance & Evidence