A valuable and direct method to access 2-substituted-2-phenyloxetanes by electrophilic quenching of the corresponding 2-lithiated derivative has, for the first time, been described. 2-Lithiated-2-phenyloxetane was found to be configurationally unstable. Evidence is presented to show that electron-transfer processes are also operative in the coupling reactions with electrophiles.

A simple and direct method to obtain 3-acyl-4-hydroxy-2-pyranone derivatives by the palladium-catalyzed carbonylation of a-chloroketones has been described. The methodology can be applied to a variety of aromatic and aliphatic ketones to afford valuable products from both a synthetic and a biological point of view. A mechanistic hypothesis involving an acylketene intermediate has also been proposed.

A high-yield one-pot two-step synthesis of 2-aminoimidazoles (2-AI), exploiting an under-air heterocyclodehydration process between α-chloroketones and guanidine derivatives, and using deep eutectic solvents (DESs) as nonconventional, "green" and "innocent" reaction media, has been accomplished successfully. The combination of either glycerol or urea with choline chloride (ChCl) proved to be effective for decreasing the reaction time to about 4-6 h in contrast to the 10-12 h usually required for the same reaction run in toxic and volatile organic solvents and under an argon atmosphere. In addition, the use of the ChCl-urea as a DES also enables the direct isolation of triaryl-substituted 2-AI derivatives by means of a simple work-up procedure consisting in filtration and crystallization, and allows the recycle of the DES mixture. A plausible mechanism highlighting the potential role played by hydrogen bonding catalysis has also been illustrated.

Regio- and stereo-selective reduction of substituted 1,3-aryldiketones, investigated in the presence of different whole cell microorganisms, was found to afford β-hydroxyketones or 1,3-diols in very good yields (up to 95%) and enantiomeric excesses (up to 96%). The enantiomerically enriched aldols, obtained with the opposite stereo-preference by baker's yeast and Lactobacillus reuteri DSM 20016 bioreduction, could then be diastereoselectively transformed into optically active syn- or anti-1,3-diols by a careful choice of the chemical reducing agent (diastereomeric ratio up to 98 : 2). The latter, in turn, were stereospecifically cyclized into the corresponding oxetanes in 43-98% yields and in up to 94% ee, thereby giving a diverse selection of stereo-defined 2,4-disubstituted aryloxetanes.

The first dynamic thermodynamic resolution of a racemic oxiranyllithium is described with selectivities of up to 82 : 18 from a selection of three types of chiral ligands (seven ligands in total). Both (-)-sparteine and its (+)-surrogate were surprisingly found to increase the enantiomerisation barrier.

Some lipophilic fluoro-substituted N-benzoyl-2-aminobenzothiazole antibacterial agents have been evaluated for their activity in the presence of cyclodextrins (CDs) containing aqueous solutions where CDs are adopted as solubilizing excipients for improving the poor water solubility of these compounds. For such purpose both the natural β-CD and one of FDA/EMA approved CDs for parenteral use (i.e. HP-β-CD) have been employed. The solubility rank order observed was accounted for by thermal analysis (Differential Scanning Calorimetry) and FT-IR spectroscopy. The most promising compound was subjected to further NMR spectroscopic studies and molecular modelling simulations to verify the interactions between the guest molecule and the CD cavity. The assessment of the antibacterial activity of such compounds against selected Gram positive and Gram negative bacterial strains clearly showed that their antimicrobial effectiveness may, quite in all instances, be positively affected by complexation with β-CD and HP-β-CD. These results, which are in some ways in contrast with those already reported in the literature, are herein discussed on the basis of plausible mechanisms. Moreover, this investigation also reveals that the described methodology of complexing both lipophilic and hydrophilic antimicrobial agents with CDs may be an useful approach to enhance their effectiveness as well as a promising strategy to overcome even the microbial resistance problem.

Cycloreversion of α-lithiated phenyltetrahydrofuran was successfully tamed at -78 °C in a non-coordinating solvent in the presence of TMEDA. This anion showed excellent nucleophilicity and could be intercepted with a variety of structurally different electrophiles to give 2,2-disubstituted derivatives which can be further elaborated to γ-butyrolactones.

This work aimed at comprehensively evaluate the potential and effectiveness of natural Deep Eutectic Solvents (DESs) for the extraction of different natural compounds from archaeological samples. We compared the procedure by DESs, which are now emerging as green and sustainable solvents, with the more conventional solvent extraction protocols, which gave measurable yields of lipid extract. The different techniques were applied on the absorbed residues of small samples of a replica pottery vessel after cooking experiments of animal fats. Direct extraction by DES and derivatization proved efficient to obtain enough fatty acids for quantification analysis of absorbed lipid residues by GC-MS. The next step was the application of DES extraction procedure on some archaeological samples previously submitted to conventional extraction methods. GC-MS analyses gave comparable results as regards the amounts and relative proportions of fatty acids identified in the archaeological samples, thus encouraging to further refine in the future the analytical protocol by DES.

A short and efficient one-pot synthesis of uracil derivatives with a high structural variability is described. The process is a multicomponent reaction based on a palladium-catalyzed carbonylation of α-chloroketones in the presence of primary amines and isocyanates. In most cases, when the formation of unsymmetrical N,N'-disubstituted uracil derivatives can occur, the methodology demonstrates to be highly regioselective. A mechanistic hypothesis involving β-dicarbonyl palladium intermediates and urea derivatives, generated in situ, has been discussed.

A mild and efficient one-pot synthesis of esters based on the Pd-catalyzed alkoxy- and aryloxycarbonylation of allylic and benzylic halides is described. The methodology has been applied to primary, secondary, and tertiary alcohols as well as to phenol derivatives. The O-protection of some biologically relevant molecules is also reported.

The first structure of an aromatic bis(trifluoroborate) dipotassium salt, elucidated by the combination of crystallography, DFT calculations, topological and non-covalent interaction analysis, discloses a 3D network undergoing spontaneous self-assembly thanks to the massive participation of weak intra- and intermolecular interactions for which fluorine atoms proved to play a leading role.

The much-anticipated Volume 26 on stereochemical aspects of organolithium compounds includes chapters on the following topics: * Asymmetric Deprotonations Using Chiral Lithium Amide Bases * Self-Regeneration of Stereocenters (SRS) via Stereolabile Axially Chiral Intermediates * Overview of Carbanion Dynamics and Electrophilic Substitutions in Chiral Organolithium Compounds * Oxiranyllithiums as Chiral Synthons for Asymmetric Synthesis * Test on the Configurational Stability/Lability of Organolithium Compounds * Mechanism and Stereochemical Features in Asymmetric Deprotonation Using RLi/(-)-Sparteine Bases * Dynamic Resolutions of Chiral Organolithiums

A range of pyrazol-5-one and pyrazol-3-one derivatives has been synthesized in a single step via a palladium- catalyzed carbonylation of aromatic or aliphatic a-chloroketones, in the presence of aromatic or aliphatic hydrazines. A reaction mechanism, explaining the observed regioselectivity, has been also discussed.

The reaction of ortho-lithiated aryloxiranes with various enaminones straightforwardly affords new functionalized isochromanes as mixtures of two epimeric stereoisomers in reasonable to very good yields (50-90%). The two diastereomers, which show a high structural variability, can be easily separated by column chromatography.

4,4-Dimethyl-2-(3-chloro-2-methyl-1-propenyl)-2-oxazoline has been synthesized and deprotonated with LDA in THF to give the corresponding lithiated species, which has been found to react a-regioselectively with NH4Cl and alkyl halides, and g-regioselectively with carbonyl compounds to afford aprotonated (or a-alkyl-substituted) regioisomers and vinyl epoxides, respectively. The Z diastereoselectivity of both the protonation and the alkylation reactions was usually found to increase with the temperature. Ab initio calculations, performed on both the naked lithium salt and the corresponding solvated form, support the observed regioselectivity.

A direct method to obtain α-alkylidene β-oxo amides by the palladium-catalyzed carbonylation of α-chloro ketones in the presence of aromatic imines has been described. The methodology can be applied to a variety of C-aryl imines bearing N-aryl or N-alkyl substituents. The entire process is highly stereoselective and affords the α-alkylidene β-oxo amides only as (Z) isomers. A mechanistic hypothesis involving an acyl-β-lactam intermediate has also been proposed.

This article reports a simple and efficient synthesis of methyl(trifluoromethyl)oxaziridines, a new family of organic oxidizing agents. A detailed study on their oxygen transfer capability with respect to styrene, thioanisole and benzyl alcohol as model substrates for the synthesis of epoxides, sulfoxides and aldehydes is described. Moreover, an oxaziridine auto-oxidation at nitrogen and/or N-benzylic carbon is also reported.

It has always been a firm conviction of the scientific community that the employment of both anhydrous conditions and water-free reaction media is required for the successful handling of organometallic compounds with highly polarised metal–carbon bonds. Herein, we describe how, under heterogeneous conditions, Grignard and organolithium reagents can smoothly undergo nucleophilic additions to gchloroketones, on the way to 2,2-disubstituted tetrahydrofurans, “on water”, competitively with protonolysis, under batch conditions, at room temperature and under air. The reactivity of the above organometallic reagents has also been investigated in conventional anhydrous organic solvents and in bio-based eutectic and low melting mixtures for comparison. The scope and limitations of this kind of reaction are discussed.