Syntheses of 1-Bromo-8-methylnaphthalene and 1-Bromo-5-methylnaphthalene.

The Diels-Alder reaction between 2-methylfuran and 3-bromobenzyne (3), which was generated under mild conditions from 1,3-dibromobenzene and lithium diisopropylamide (LDA), gives a mixture of regioisomeric 1,4-dihydro-1,4-epoxynaphthalenes 4 and 5. A subsequent two-step deoxygenation affords the corresponding 1-bromo-8-methylnaphthalene (1) and 1-bromo-5-methylnaphthalene (2) in high yields.