2-Cyclopenten-1-one → (3R)-3-[4-Bromo-3-(trifluoromethyl)phenyl]cyclopentanone

Participants

Reaction Steps

2-[4-bromo-3-(trifluoromethyl)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (3.0 g, 8.5 mmol) (Preparation 5) and [Rh(R-BINAP)(nbd)]BF4 (155 mg) were dissolved in a de-gassed solution of 2-cyclopenten-1-one (0.70 g) in 1,4-dioxane (12.8 mL), water (2.5 mL), and triethylamine (1.2 mL) in a microwave vial and irradiated in a microwave reactor at 120° C. for 5 min. MTBE was added and the mixture was washed 3 times with water. The organic phase was dried, concentrated under reduced pressure and purified by flash chromatography (100% heptane->70% EtOAc/Heptane) to obtain the title compound. 1H NMR (300 MHz, CDCl3) δ 7.68 (d, J=8.2, 1H), 7.57 (d, J=2.2, 1H), 7.28 (dd, J=8.4, 2.3, 1H), 3.51-3.36 (m, 1H), 2.76-2.64 (m, 1H), 2.56-2.23 (m, 4H), 2.06-1.89 (m, 1H).

Provenance & Evidence