INSERTION D'ALLENES. VIII. FORMATION DE CETONES α,β-INSATUREES PAR HYDROACYLATION D'ALLENES EN PRESENCE DE TETRACARBONYL FERRATE DE SODIUM

Article abstract of DOI:10.1016/S0022-328X(00)96194-1

α,β-Unsaturated ketones are generated in moderate yields (50-60percent) from allene or a mono-, di- or tri-substituted allenic hydrocarbon, an alkyl halide and sodium tetracarbonylferrate.The first step is the formation of a complex anion which results from transfer of the alkyl group on a coordinated CO, then of the acyl ligand thus formed on the allenic sp carbon.Protonation with acetic acid yields a hydroxy-η⁴-trimethylenemethane, easily isomerised into an η⁴-heterodieneiron tricarbonyl.Finally, the α,β-unsaturated ketone is released upon oxidation with trimethylamine oxide.The most substituted ketone predominates.