Boron trifluoride etherate → 8-Fluoro-1-tetralone

Participants

Reaction Conditions

Reaction Steps

The amine (Intermediate J3, 1.83 g, 11.3 mmol) in CH2Cl2 (17 mL) was added to BF3.OEt2 (2.80 mL, 22.1 mmol) at −15° C. More CH2Cl2 (20 mL) was added to the precipitate. Next, t-butyl nitrite (1.8 mL, 12.9 mmol) in CH2Cl2 (20 mL) was added at −15° C. and stirred for 10 min. and at 0° C. for 20 m. The mixture was diluted with pentane (40 mL), filtered and the solids were collected, washed with ether, and dried under vacuum. The solids were placed in a flask and heated to 115° C. for 10-15 min. followed by addition of 2N NaOH and CHCl3. The suspension was filtered and the aqueous phase was extracted with CHCl3. The organic layers were combined, dried over MgSO4, filtered and purified by chromatography on SiO2 with 15% EtOAc:Hx. The product, 8-fluoro-3,4-dihydro-2H-naphthalen-1-one (Intermediate J4) was isolated; 750 mg (40%).

Provenance & Evidence