Synthesis and reactions of 3,3-dimethylallyl derivatives of acetylacetone and other poly-β-carbonyl compounds

Abstract

Alkylation of acetylacetone, and of a number of related triketones and lactones, with 3,3-dimethylallyl bromide and 3,3-dimethylallyl diphenyl phosphate gives C-alkylated products under a variety of experimental conditions. The C- and O-(3,3-dimethylallyl) derivatives of acetylacetone undergo ready cyclisation and Claisen rearrangement reactions, respectively, to give products whose isoprenoid part-structures are similar to those found in phenolic isoprenoids. Acetylacetone is converted into 4-bromopent-3-en-2-one under mild conditions by treatment with triphenylphosphine dibromide.