Monica Orsini

Synthesis of chiral oxazolidin-2-ones by 1,2-amino alcohols, carbon dioxide and electrogenerated acetonitrile anion

An improved electrochemical synthesis of chiral oxazolidin-2-ones from chiral 1,2-amino alcohols is obtained by direct electrolysis of solutions of MeCN–TEAP containing the amino alcohol, with subsequent CO2 bubbling and addition of TsCl. This synthesis avoids any addition of bases or probases and yields oxazolidinones in high yields.

Asymmetric carbolithiation of 2-phenylselenofumarate derivatives: a short synthesis of (−)-roccellaric acid

Abstract (−)-Roccellaric acid and variously substituted succinates are obtained through direct asymmetric carbolithiation of 2-phenylselenofumarate derivatives, followed by reaction with suitable electrophiles.

Electrochemically induced Knoevenagel condensation in solvent- and supporting electrolyte-free conditions

Solvent- and supporting electrolyte-free electrochemically induced Knoevenagel condensation of malononitrile with aldehydes or ketones, at 40 °C, yields ylidenemalononitriles in high yields.

Electrochemically-initiated Michael addition of chiral acetoacetic derivatives to methyl vinyl ketone: stereocontrolled construction of quaternary carbon centers

Abstract Stereoselective conjugate addition of chiral β-dicarbonyl derivatives to methyl vinyl ketone was promoted by electrolysis, using a catalytic amount of electricity. With respect to the metal-catalyzed methods, the electrochemical, metal-free conditions resulted in enhanced reactivity of the electrogenerated enolates, so that the Michael addition was found to occur under mild conditions and short reaction times, affording products with significant diastereoisomeric excesses. When Oppolzers sultam was used as the chiral inductor and prolonged reaction times were employed, a reversal in the stereoselectivity was observed, evidencing kinetic control in the electrochemically-induced addition and subsequent thermodynamic equilibration. The electrochemically-based method was also exploited for the elaboration of quaternary stereogenic carbon centers.

Electrochemical generation of tetraethylammonium N-acetoacetyloxazolidin-2-one enolates: an easy access to α-alkylated acetoacetic derivatives

A new electrochemical method for the mild generation of naked β-dicarbonyl derivative enolates is disclosed. The electrolysis, under galvanostatic control, of a solution of N-acetoacetyloxazolidin-2-ones/acetonitrile/tetraethylammonium perchlorate allowed the selective α-monoalkylation of the 1,3-dicarbonyl residue with a variety of alkyl halides, in very good yields and short reaction times. More interestingly, no by-products arising from either the electroreduction of the carbonyl functionalities or from nucleophilic cyanomethyl anion attack were detected.

An innovative strategy for electrochemically-promoted addition reactions

A new strategy based on the catalytic release of the supporting electrolyte agent in the electrolysis medium proved to be effective for the direct electroactivation of suitable C-H acid-containing compounds vs. catalytic addition processes, under solvent-free conditions.

An efficient electrochemical method for N-acryloylation of oxazolidin-2-one chiral auxiliaries with α, α'-di- and trichloroketones

Abstract A new synthesis of N-enoyloxazolidin-2-ones has been performed by electrochemical reduction of α,α′-di- and trichloroketones in aprotic solvent in the presence of Evans’ chiral auxiliaries (oxazolidin-2-ones). The electrochemical reduction of trichloroketones via a chlorocyclopropanone as intermediate allows a Favorskii rearrangement involving trichloroketones and oxazolidin-2-ones. N-Enoyloxazolidin-2-ones have been obtained this way under mild reaction conditions and in good to high yields.

Manganese-containing mixed oxide electrodes as anode materials for degradation of model organic pollutants

Mixed oxide thin film electrodes have been prepared by thermal decomposition from alcoholic solution on Pt substrate. In particular, three different anodes have been obtained by co-deposition of Ru (Ruthenium) and Mn (Manganese) oxides, Ru, Mn and Cu (Copper) oxides and co-deposition of Ru, Mn and Co (Cobalt) oxides. The electrochemical behaviour of the prepared electrodes was evaluated by potentiodynamic polarization curves and cyclic voltammetry tests. We also tested and compared their oxidizing ability in the degradation of aqueous solutions containing methyl orange as model compound and small amount of chloride. Galvanostatic experiments were conducted in a membrane-free reactor. The treatment extent was assessed by detection of color and TOC decay. The electrogeneration of active chlorine, chlorate and perchlorate was also monitored. The preliminary results show that ternary oxides coated electrodes exhibit enhanced electrocatalytic activity without producing undesired chlorinated by-products.

Reactivity of Electrogenerated Imidazole-2-Ylidenes in Ionic Liquids: Synthetic Implications

The cathodic reduction of an imidazolium ionic liquid, under galvanostatic conditions, leads to the formation of the corresponding carbene, imidazole-2-ylidene, and molecular hydrogen. This carbene can behave as a base and/or as a nucleophile, depending on the reaction partner. In particular, we have studied the reactivity of this N-heterocyclic carbene in alkylation and acylation reactions, in the synthesis of β-lactams, in the Henry reaction, in the synthesis of thiones and in the benzoin condensation

Room Temperature Ionic Liquids (RTILs) Versus Volatile Organic Compounds (VOCs) in Organic Electrosynthesis: The Requirement of a Careful Comparison

The possible utilization of room temperature ionic liquids (RTILs), instead of volatile organic compounds (VOCs), in the electrochemical procedures of organic synthesis has been discussed. The synthesis of β − lactams, the activation of carbon dioxide and its utilization as renewable carbon source and the carbon–carbon bond formation reactions via umpolung of aldehydes (benzoin condensation and Stetter reaction) and via Henry reaction have been selected as typical electrochemical methodologies. The results, related to procedures performed in RTILs, have been compared with those performed in VOCs. The double role of RTILs, as green solvents and parents of electrogenerated reactive intermediates or catalysts, has been emphasized.