THE DIELS-ALDER AND RING ENLARGEMENT REACTIONS OF 1-CYCLOBUTENYL KETONES. PREPARATION OF 1-ACETYL-1,3,5-CYCLOOCTATRIENES

Article abstract of DOI:10.1016/S0040-4039(00)82326-6

The Diels-Alder reaction of 1-cyclobutenyl ketones with various 1,3-dienes in the presence of Lewis acid as a catalyst gave cycloadducts in good yields. 4-Acetylcyclooctadienones and 1-acetyl-1,3,5-cyclooctatrienes are obtained via the bicyclo<4.2.0>octa-2,4-dienes by the transformation to the trimethylsilyl enol ether or the allylic bromination with N-bromosuccinimide followed by dehydrobromination of the cycloadducts.