Organocatalytic CS insertion into epoxides in neat conditions: a straightforward approach for the efficient synthesis of Di- and tri-thiocarbonates.

The straightforward organocatalytic insertion of carbon disulfide (CS) into epoxides using either choline chloride () or tetrabutylammonium chloride (TBACl) is reported, for the first time, under solvent-free (neat) conditions. Fine-tuning of our system allowed us to obtain either dithiocarbonates (DTCs) or trithiocarbonates (TTCs) with high efficiency. Additionally, a mechanistic proposal is presented, supported by experimental evidence, DFT calculations and wavefunction analyses.

Access to Substituted 1,1-Diarylalkanes by Friedel-Crafts Benzylations Mediated by FeCl-based Deep Eutectic Solvents.

The development of new, more efficient Friedel-Crafts benzylation methodologies that provide access to 1,1-diarylalkanes is an important objective of interest for the production of pharmaceuticals and fine chemical products. In this regard, this study introduces a novel synthetic route to 1,1-diarylalkanes conducted in the Deep Eutectic Solvent (DES) 3 FeCl ⋅ 6 HO/Gly, which serves as both a reaction medium and promoter. Under these conditions, Friedel-Crafts benzylations of various arenes bearing activating and deactivating ortho-/para-directing groups, can be performed using diverse benzylating reagents such as styrenes, alcohols, acetates, ethers, and chlorides.

Fe -Based Eutectic Mixtures as Multi-task and Reusable Reaction Media for Efficient and Selective Conversion of Alkynes into Carbonyl Compounds.

Invited for the cover of this issue is the group of Vicente del Amo, Alejandro Presa Soto and Joaquín García-Álvarez (QuimSinSos Group) at the University of Oviedo. The image depicts the use of the Fe -based deep eutectic mixture [FeCl ⋅6 H O/Gly (3:1)] (Gly = glycerol) as both promoter and solvent for the straightforward and selective hydration of alkynes, working under mild (45 °C), bench-type reaction conditions (air) and in the absence of ligands, co-catalysts or co-solvents. Read the full text of the article at 10.

Fe -Based Eutectic Mixtures as Multi-task and Reusable Reaction Media for Efficient and Selective Conversion of Alkynes into Carbonyl Compounds.

An efficient, simple and general protocol for the selective hydration of terminal alkynes into the corresponding methyl ketones has been developed by using a cheap, easy-to-synthesise and sustainable Fe -based eutectic mixture [FeCl  ⋅ 6H O/Gly (3 : 1)] as both promoter and solvent for the hydration reaction, working: i) under mild (45 °C) and bench-type reaction conditions (air); and ii) in the absence of ligands, co-catalysts, co-solvents or toxic, non-abundant and expensive noble transition metals (Au, Ru, Pd). When the final methyl ketones are solid/insoluble in the eutectic mixture, the hydration reaction takes place in 30 min, and the obtained methyl ketones can be isolated by simply decanting the liquid Fe -DES, allowing the direct isolation of the desired ketones without VOC solvents. By using this straightforward and simple isolation protocol, we have been able to recycle the Fe -based eutectic mixture system up to eight consecutive times.

Aerobic/Room-Temperature-Compatible s-Block Organometallic Chemistry in Neat Conditions: A Missing Synthetic Tool for the Selective Conversion of Nitriles into Asymmetric Alcohols.

Highly-efficient and selective one-pot/two-step modular double addition of different highly polar organometallic reagents (RLi/RMgX) to nitriles en route to asymmetric tertiary alcohols (without the need for isolation/purification of any halfway reaction intermediate) has been studied, for the first time, in the absence of external/additional organic solvents (neat conditions), at room temperature and under air/moisture (no protecting atmosphere is required), which are generally forbidden reaction conditions in the field of highly-reactive organolithium/organomagnesium reagents. The one-pot modular tandem protocol demonstrated high chemoselectivity with a broad range of nitriles, as no side reactions (Li/halogen exchange, ortho-lithiations or benzylic metalations) were detected. Finally, this protocol could be scaled up, thus proving that this environmentally friendly methodology is amenable for a possible applied synthesis of asymmetric tertiary alcohols under bench type reaction conditions and in the absence of external organic solvents.

Dipyrromethane-Based PGeP Pincer Germyl Rhodium Complexes.

A family of germyl rhodium complexes derived from the PGeP germylene 2,2'-bis(di-isopropylphosphanylmethyl)-5,5'-dimethyldipyrromethane-1,1'-diylgermanium(II), Ge(pyrmP Pr ) CMe (1), has been prepared. Germylene 1 reacted readily with [RhCl(PPh ) ] and [RhCl(cod)(PPh )] (cod=1,5-cyclooctadiene) to give, in both cases, the PGeP-pincer chloridogermyl rhodium(I) derivative [Rh{κ P,Ge,P-GeCl(pyrmP Pr ) CMe }(PPh )] (2). Similarly, the reaction of 1 with [RhCl(cod)(MeCN)] afforded [Rh{κ P,Ge,P-GeCl(pyrmP Pr ) CMe }(MeCN)] (3).

Ligand-Free Copper-Catalyzed Ullmann-Type C-O Bond Formation in Non-Innocent Deep Eutectic Solvents under Aerobic Conditions.

An efficient and novel protocol was developed for a Cu-catalyzed Ullmann-type aryl alkyl ether synthesis by reacting various (hetero)aryl halides (Cl, Br, I) with alcohols as active components of environmentally benign choline chloride-based eutectic mixtures. Under optimized conditions, the reaction proceeded under mild conditions (80 °C) in air, in the absence of additional ligands, with a catalyst [Cu or Cu species] loading up to 5 mol% and K CO as the base, providing the desired aryloxy derivatives in up to 98 % yield. The potential application of the methodology was demonstrated in the valorization of cheap, easily available, and naturally occurring polyols (e.

Copper-catalyzed Goldberg-type C-N coupling in deep eutectic solvents (DESs) and water under aerobic conditions.

An efficient and selective N-functionalization of amides is first reported via a CuI-catalyzed Goldberg-type C-N coupling reaction between aryl iodides and primary/secondary amides run either in Deep Eutectic Solvents (DESs) or water as sustainable reaction media, under mild and bench-type reaction conditions (absence of protecting atmosphere). Higher activities were observed in an aqueous medium, though the employment of DESs expanded and improved the scope of the reaction to include also aliphatic amides. Additional valuable features of the reported protocol include: (i) the possibility to scale up the reaction without any erosion of the yield/reaction time; (ii) the recyclability of both the catalyst and the eutectic solvent up to 4 consecutive runs; and (iii) the feasibility of the proposed catalytic system for the synthesis of biologically active molecules.

Deep eutectic solvent-catalyzed Meyer-Schuster rearrangement of propargylic alcohols under mild and bench reaction conditions.

The Meyer-Schuster rearrangement of propargylic alcohols into α,β-unsaturated carbonyl compounds has been revisited by setting up an atom-economic process catalyzed by a deep eutectic solvent FeCl3·6H2O/glycerol. Isomerizations take place smoothly, at room temperature, under air and with short reaction times. The unique solubilizing properties of the eutectic mixture enabled the use of a substrate concentration up to 1.

Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents.

Lithium amides constitute one of the most commonly used classes of reagents in synthetic chemistry. However, despite having many applications, their use is handicapped by the requirement of low temperatures, in order to control their reactivity, as well as the need for dry organic solvents and protective inert atmosphere protocols to prevent their fast decomposition. Advancing the development of air- and moisture-compatible polar organometallic chemistry, the chemoselective and ultrafast amidation of esters mediated by lithium amides is reported.

Special Issue: "Advances in Homogeneous Catalysis".

The use of enzymes, organo-catalysts or transition metal catalysts, as opposed to the employment of stoichiometric quantities of other traditional promoters of different organic synthetic processes (like, inorganic/organic bases, Brønsted acids, radicals, etc.) has allowed the discovery of a great number of new synthetic protocols within the toolbox of organic chemists. Moreover, the employment of the aforementioned catalysts in organic synthesis permits: () the diminution of the global energy demand and production cost; () the enhancement of both the chemoselectivity and stereoselectivity of the global process; and () the reduction of metal-, organo- or bio-catalyst consumption, thanks to the possible recycling of the catalysts; all these being synthetic concepts closely related with the principles of so-called Thus, this Special Issue on "" has been aimed to showcase a series of stimulating contributions from international experts within different sub-areas of catalysis in organic synthesis (ranging from metal-, organo-, or bio-catalyzed organic reactions).

ign of Sustainable Chemoenzymatic Organic Transformations in for the Synthesis of 1,2-Disubstituted Aromatic Olefins.

The self-assembly of styrene-type olefins into the corresponding stilbenes was conveniently performed in the () mixture 1/2 under air and in the absence of hazardous organic co-solvents using a one-pot chemo-biocatalytic route. Here, an enzymatic decarboxylation of -hydroxycinnamic acids sequentially followed by a ruthenium-catalyzed metathesis of olefins has been investigated in . Moreover, and to extend the design of chemoenzymatic processes in , we also coupled the aforementioned enzymatic decarboxylation reaction to now concomitant Pd-catalyzed Heck-type C-C coupling to produce biaryl derivatives under environmentally friendly reaction conditions.

s-Block cooperative catalysis: alkali metal magnesiate-catalysed cyclisation of alkynols.

Mixed s-block metal organometallic reagents have been successfully utilised in the catalytic intramolecular hydroalkoxylation of alkynols. This success has been attributed to the unique manner in which these reagents can overcome the challenges of the reaction: namely OH activation and coordination to and then addition across a C[triple bond, length as m-dash]C bond. In order to optimise the reaction conditions and to garner vital catalytic system requirements, a series of alkali metal magnesiates were enlisted for the catalytic intramolecular hydroalkoxylation of 4-pentynol.