Luigi Lopez

Heck reaction in ionic liquids catalyzed by a Pd–benzothiazole carbene complex

Abstract A Pd-catalyst with benzothiazole carbene ligands allows, in ionic liquids as solvent, very fast and efficient reactions of haloaromatics with alkenes.

Heck reaction of β-substituted acrylates in ionic liquids catalyzed by a Pd-benzothiazole carbene complex

Abstract A Pd-catalyst with benzothiazole carbene as ligands allows, in tetrabutylammonium bromide melt as solvent, very fast and efficient reactions of haloaromatics with β-substituted acrylates.

Arylation of α-substituted acrylates in ionic liquids catalyzed by a Pd–benzothiazole carbene complex

Abstract A Pd-catalyst with benzothiazole carbene as ligands allows, in tetrabutylammonium bromide melt as solvent, very fast and efficient reactions of bromoaromatics with 3-hydroxy-2-methylenealkanoates to give β-arylketones.

Aerobic oxidations of unsaturated substrates under mukaiyama's conditions: The role of the metal and of the sacrificial aldehyde

Abstract Aerobic epoxidation of unsaturated substrates has been achieved under Mukaiyamas conditions (atmospheric pressure of dioxygen, in the presence of an excess of sacrificial aldehyde) with or without metal catalyst. The influence of light in non-catalysed reactions and the possible role of the aldehyde and of the metal complex in catalysed reactions are discussed. Two mechanistic pathways are proposed for Co(II) and Fe(III) [Ni(II)] catalytic centres.

Oxidations by methyl trifluoromethyl dioxirane. Epoxidation of enol ethers

Abstract Isolated methyl trifluoromethyl dioxirane 4b has been employed to achieve the rapid, low temperature epoxidation of enol ethers, such as alkoxy(aryl)methylidene adamantanes 1a–e and methoxy(2-naphthyl)methylidene 2-bornane 1f , affording the corresponding spirooxiranes in excellent (92–97%) yields.

Stereoselective synthesis of electrophilic spirocyclopropanes in ionic liquids

Abstract The reaction of β-oxosulfides of benzothiazole with Michael acceptors, in liquid tetrabutylammonium bromide and sodium bicarbonate as base, allows a stereoselective synthesis of spirocyclopropanes.

Electron-transfer chain isomerization of epoxides induced by one-electron oxidizing agents

Abstract One electron oxidizing agents have been employed to achieve the isomerization of epoxides to ketones. The reactions most likely proceed via a radical cation chain electron-transfer mechanism.

Contribution to the bromination of conjugate unsaturated ketones: Synthesis of α,β-unsaturated bromo ketones

Abstract Selective bromination of α,β-unsaturated ketones has been achieved by the action of 2,4,4,6-tetrabromocyclohexa-2,5-dienone. The stereochemistry, conformation and relative stability of the bromination products of some steroidic unsaturated ketones have been also determined.

Aerobic oxidation of α-hydroxyketones catalysed by cobalt(II) and iron(III) complexes under homogeneous and heterogeneous conditions

Abstract Aromatic α-hydroxyketones were easily oxidized by dioxygen in the presence of excess aldehyde or aldoacetal with catalytic amount of Co(II) or Fe(III) complexes, under homogeneous and heterogeneous conditions. Co(acac) 2 or Fe(acac) 3 were the catalysts used in homogeneous phase reactions whereas Co(II) or Fe(III) supported complexes, obtained by copolymerization of Co(AAEMA) 2 or Fe(AAEMA) 3 (AAEMA − = deprotonated form of 2-(acetoacetoxy)ethyl methacrylate) with acrylamides, were the heterogeneous catalysts. The supported metal complexes were recyclable and did not suffer from metal leaching.

Aminium salts catalyzed rearrangement of α-pinene and β-ionone oxides

Abstract β-ionone and α-pinene oxides 1, 3 isomerize rapidly and selectively to 1-(1,2,2-trimethylcyclopent-1-yl)-pent-2-en-1,4-dione 2 and the industrialy important 2,2,3-trimethyl-3-cyclopentene acetaldehyde 4 . under the influence of catalytic amounts of aminium salts A,B . In order to find insights into the mechanism of our procedure, protic and Lewis acid-catalyzed rearrangements have also been reconsidered.