5-(3-bromophenyl)pentanoic Acid → 2-bromo-6,7,8,9-tetrahydro-5H-benzo(7)annulen-5-one

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Reaction Steps

To a solution of 5-(3-Bromo-phenyl)-pentanoic acid (6 g, 23 mmol) in chlorobenzene (300 mL) was added PPA (18 g) and the mixture was heated to reflux for 8 h. The mixture was cooled to rt and filtered. The filtrate was concentrated under reduced pressure then purified by silica gel chromatography using a solvent system of 10:1 petroleum ether/EtOAc to give 2-bromo-6,7,8,9-tetrahydro-benzocyclohepten-5-one (2.4 g, 42.9%). MS ESI calcd for C11H11BrO [M+H]+ 239, found 239.

Provenance & Evidence