Dihydrobenzofuran → 5-Methyl-2,3-dihydro-1-benzofuran

To a chilled (10° C.) solution of 10 g (83 mmol) of 2,3-dihydrobenzofuran in 50 mL of acetic acid, 4 mL (78 mmol) of bromine in 6 mL of acetic acid was added dropwise over a 10 minute period. After 1 hour, the mixture was made basic by cautiously pouring the reaction mixture into saturated/solid aqueous sodium bicarbonate and stirring overnight. The mixture was then extracted with three 100 mL portions of EtOAc. The combined organic layers were washed with two 50 mL portions of saturated aqueous sodium bicarbonate, three 50 mL portions of brine, dried over magnesium sulfate, filtered, and concentrated to afford a yellow oil. The oil was diluted with hexane and passed through a pad (600 mL funnel) of silica gel eluting with hexane to afford a white solid which was diluted with cold (dry ice-acetone) hexane and collected by filtration to afford 4.7 g (28%) of the title compound as a white solid, m.p. 45° C.-48° C. The filtrate was concentrated to afford 5.1 g of 5-bromo-2,3-dihydrobenzofuran which was 70% pure.

1. additionwas added dropwise over a 10 minute period
2. extractionThe mixture was then extracted with three 100 mL portions of EtOAc
3. washThe combined organic layers were washed with two 50 mL portions of saturated aqueous sodium bicarbonate, three 50 mL portions of brine
4. dry with materialdried over magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated
7. customto afford a yellow oil
8. customto afford a white solid which
9. filtrationcollected by filtration

ORD record

ord-35d9257c4206427a87ee621582da726f

Source dataset

uspto-grants-2007_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07268152B2