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

Temperature

100 °C

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)

1. customThe reaction vessel was degassed several times
2. additionWater (4 mL) was added
3. temperaturebefore cooling
4. washwashing with saturated aqueous sodium hydrogen carbonate solution (50 mL)
5. extractionThe mixture was extracted with EtOAc (2×100 mL)
6. customthe organics dried
7. customthen purified by chromatography
8. washeluting with 0-40% EtOAc/isohexane)

ORD record

ord-934742ba62ac46a487b2da9c668c2a1f

Source dataset

uspto-grants-2010_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07795283B2