Boron tribromide → 6-hydroxy-4,4-dimethyl-3,4-dihydronaphthalen-1(2H)-one

To a solution of 6-methoxy-4,4-dimethyl-3,4-dihydronaphthalen-1(2H)-one (1.0 g, 4.90 mmol) in dichloromethane (50 mL) at 0° C. was slowly added tribromoborane (1.0 M in dichloromethane) (24.5 mL, 24.5 mmol), resulting in a dark solution. The ice-bath was removed, and the reaction mixture was stirred overnight. The reaction mixture was diluted with dichloromethane (100 mL) and washed with water (2×25 mL). The aqueous layer was extracted with dichloromethane (2×25 mL), and the combined organic layers were dried over anhydrous sodium sulfate and concentrated to give a red, viscous oil. The residue was purified by flash silica gel chromatography using a mixture of ethyl acetate in hexane (5%-12.5%-20%) to give 6-hydroxy-4,4-dimethyl-3,4-dihydronaphthalen-1(2H)-one (0.299 g, 1.57 mmol, 32% yield) as an orange solid. The product had an HPLC ret. time=1.68 min. (condition A); LC/MS M+1=190.9.

1. customat 0° C.
2. customresulting in a dark solution
3. customThe ice-bath was removed
4. additionThe reaction mixture was diluted with dichloromethane (100 mL)
5. washwashed with water (2×25 mL)
6. extractionThe aqueous layer was extracted with dichloromethane (2×25 mL)
7. dry with materialthe combined organic layers were dried over anhydrous sodium sulfate
8. concentrationconcentrated
9. customto give a red, viscous oil
10. customThe residue was purified by flash silica gel chromatography
11. additiona mixture of ethyl acetate in hexane (5%-12.5%-20%)

ORD record

ord-68f9e98da002498582ec43475dad0f6c

Source dataset

uspto-grants-2015_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09216972B2