Novel rearrangement and cyclization processes resulting from bromination of 1,1-dibenzyltetralin derivatives

Addition of bromine to hydrocarbon 1 results in an aromatic alkylation to form the bicyclo[3.3.1]nonane derivative 5. Addition of bromine to ketone 3 in acetonitrile solution results in a dienone-phenol rearrangement to form phenol 6, while reaction of ketone 4 with phosphorus pentabromide yields phenols 10 and 11. This reaction results from a novel "bromo ketone-phenol" rearrangement, as demonstrated by the fact that bromo ketones 12 and 13 spontaneously isomerize to 10 and 11.