Francesco Ciminale

Glucose as a Clean and Renewable Reductant in the Pd-Nanoparticle-Catalyzed Reductive Homocoupling of Bromo- and Chloroarenes in Water

An efficient and highly sustainable Ullmann-type homocoupling of bromo- and chloroarenes, including the more challenging electron-rich chloroarenes (e.g., 4-chloroanisole), catalyzed by in situ generated Pd colloids, is carried out in aqueous medium under relatively mild conditions (temperatures ranging from 40 to 90 degrees C). Glucose is used as a clean and renewable reductant, while tetrabutylammonium hydroxide (TBAOH) acts as base, surfactant, and phase-transfer agent, creating a favorable environment for the catalyst. Pd nanoparticle sizes, morphology, and chemical composition are ascertained by TEM and XPS analyses.

Palladium/Zirconium Oxide Nanocomposite as a Highly Recyclable Catalyst for C-C Coupling Reactions in Water

Palladium nanoparticles have been electrochemically supported on zirconium oxide nanostructured powders and all the nanomaterials have been characterized by several analytical techniques. The Pd/ZrO2 nanocatalyst is demonstrated to be a very efficient catalyst in Heck, Ullmann, and Suzuki reactions of aryl halides in water. The catalyst efficiency is attributed to the stabilization of Pd nanophases provided by tetra(alkyl)-ammonium hydroxide, which behaves both as base and PTC (phase transfer catalyst) agent.

Oxidations by methyl(trifluoromethyl)dioxirane. 4.1 oxyfunctionalization of aromatic hydrocarbons

Abstract By using the title dioxirane ( 1a ), naphthalene ( 2 ), phenanthrene ( 3 ), and anthracene ( 4 ) have been converted into anti -naphthalene-1,2;3,4-dioxide ( 2′ ), phenonthrene-9,10-oxide ( 3′ ), and anthraquinone ( 4′ ), respectively, in high yield and under mild conditions. However, the transformation of pyrene ( 5 ) - an higher homologue of the polycyclic aromatic hydrocarbon series - into the corresponding arene oxide was found to procced much less effectively.

Palladium‐Catalyzed Cross‐Coupling of Styrenes with Aryl Methyl Ketones in Ionic Liquids: Direct Access to Cyclopropanes

The combined use of Pd(OAc)2 , Cu(OAc)2 , and dioxygen in molten tetrabutylammonium acetate (TBAA) promotes an unusual cyclopropanation reaction between aryl methyl ketones and styrenes. The process is a dehydrogenative cyclizing coupling that involves a twofold CH activation at the α-position of the ketone. The substrate scope highlights the flexibility of the catalyst; a reaction mechanism is also proposed.

Ring opening of benzothiazoles with allylic grignard reagents

Abstract A novel ring opening reaction of the benzothiazole system with allylic Grignard reagents is reported. A possible mechanism is presented.

Adducts of silyl, germyl and stannyl radicals with heterocyclic α-diketones: an electron spin resonance investigation

Hyperfine coupling constants are reported for adducts of silyl, germyl and stannyl radicals with a series of substituted benzo [b]thiophen-2,3-diones (Ia—Ip), benzo [b] furan-2,3-dione (II), ninhydrin (III), and thieno [ 3,2-b] thiophen-2,3-dione (IV). The conformational and electronic properties of these radicals are compared with those of similar adducts formed by diaryl ketones.

Organometallic induced self-condensation of carboxamides

Abstract N,N-Disubstituted carboxamides containing α-hydrogen atoms undergo self-condensation reaction simply on treatment with Grignard reagents or n-BuLi in THF room temp. The reaction is considerably influenced steric hindrance at the α-carbon and the condensing agent utilized. A possble Claisen-type mechanism is also reported.

Aminium salts-induced dimerization of α-methylstyrene and 1-aryl-1-phenylethylenes. Solvent effect

Abstract The aminium salts-induced dimerization of α-methylstyrene 1b gives rise, depending on the solvent employed, to high yields of 1,3,3-trimethyl-1-phenylindane 2b , or 2,4-diphenyl-4-methyl-1-pentene 6b . Several 1-aryl-1-phenylethylenes 1a,c-e afford, instead, cyclodimers 2a,c-e , or 2,5-diaryl-2,5-diphenyltetrahydrofuran derivatives 3a,c-e .

Direct monobromination of imidazole and N-methylimidazole

Monobromination of imidazole, N-methylimidazole, and indole is achieved in high yield by treatment with 2,4,4,6-tetrabromocyclohexa-2,5-dienone.

Reactions on aromatic olefins induced by aminium salts: protic-acid or radical cation catalyzed processes

Abstract Aromatic olefins by reaction with aminium salts lead, in strongly acidic reaction media, to different reaction products, arising from the intermediate formation of carbocation or radical-cation species.