Chromium Mediated Organic Synthesis: The Introduction of 1,1-Dimethylallyl and Linalyl Groups on to Arenes

The synthesis of 1,1-dimethylallyl-substituted benzene-and anisoletricarbonylchromium(0) complexes was achieved in a two- or three-step sequence by the copper catalysed coupling of the lithiated arenetricarbonylchromium(0) complexes with allyl bromide followed by a double benzylic alkylation with potassium tert-butoxide/methyl iodide. For the linalyl substituted complexes the alkylations were sequential homoprenylation and methylation. Alternatively, palladium catalysed cross coupling with 2-bromo-2-butene followed by γ-deprotonation of the 1-aryl-1-propene complexes provided a more direct approach to the anionic intermediates involved.