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ABSTRACT The electrochemically driven asymmetric hydrogenation of 2,2,2‐trifluoroacetophenone was performed using a Noyori–Ikariya catalyst, yielding a 97% product yield and a 47% enantiomeric excess (ee) with a charge input of only 0.5 F/mol. In comparison, the ethoxylate anion generated by the electroreduction of the solvent, EtOH, can efficiently drive the transfer hydrogenation of Ru catalysts more effectively than organic bases. After optimizing the electrolysis conditions, this method has been successfully extended to other aromatic ketones, including heterocyclic aromatic ketones and the base‐sensitive substrate ethyl benzoylformate, with yields ranging from 71% to 97% and ee values ranging from 55% to 82%. A possible reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

The oxidation of benzylic alcohols is an important transformation in modern organic synthesis. A plethora of photoredox protocols have been developed to achieve the aerobic oxidation of alcohols into carbonyls. Recently, several groups described that ultraviolet (UV) or purple light can initiate the aerobic oxidation of benzylic alcohols in the absence of an external catalyst, and depicted different mechanisms involving the photoinduction of •O2− as a critical reactive oxygen species (ROS). However, based on comprehensive mechanistic investigations, including control experiments, radical quenching experiments, EPR studies, UV–vis spectroscopy, kinetics studies, and density functional theory calculations (DFT), we elucidate here that HOO•, which is released via the H2O2 elimination of α-hydroxyl peroxyl radicals [ArCR(OH)OO•], serves as the real chain carrier for the autocatalytic photooxidation of benzylic alcohols. The mechanistic ambiguities depicted in the precedent literature are clarified, in terms of the crucial ROS and its evolution, the rate-limiting step, and the primary radical cascade. This work highlights the necessity of stricter mechanistic analyses on UV-driven oxidative reactions that involve aldehydes' (or ketones) generation. [ABSTRACT FROM AUTHOR]

With KI as the supporting electrolyte and a mediator, DMSO as the solvent and KHCO3 as the base, a convenient and efficient electrochemical route was developed for the synthesis of polysubstituted oxazoles from aromatic ketones and benzylamines. The electrosynthesis was smoothly carried out in an undivided cell at room temperature, affording the target products in moderate to high yields. [ABSTRACT FROM AUTHOR]

The oxidation of benzylic alcohols is an important transformation in modern organic synthesis. A plethora of photoredox protocols have been developed to achieve the aerobic oxidation of alcohols into carbonyls. Recently, several groups described that ultraviolet (UV) or purple light can initiate the aerobic oxidation of benzylic alcohols in the absence of an external catalyst, and depicted different mechanisms involving the photoinduction of •O2− as a critical reactive oxygen species (ROS). However, based on comprehensive mechanistic investigations, including control experiments, radical quenching experiments, EPR studies, UV–vis spectroscopy, kinetics studies, and density functional theory calculations (DFT), we elucidate here that HOO•, which is released via the H2O2 elimination of α-hydroxyl peroxyl radicals [ArCR(OH)OO•], serves as the real chain carrier for the autocatalytic photooxidation of benzylic alcohols. The mechanistic ambiguities depicted in the precedent literature are clarified, in terms of the crucial ROS and its evolution, the rate-limiting step, and the primary radical cascade. This work highlights the necessity of stricter mechanistic analyses on UV-driven oxidative reactions that involve aldehydes’ (or ketones) generation.

Based on Friedel Crafts acylation, an efficient and facile method for the chemo-selective as well as region-selective acylation of substituted benzene derivatives has been developed by using Hg[Co(SCN)4] as catalyst. The reaction is highly chemo-selective as well as region-selective as only acetophenones were obtained, whereas the benzophenones are not formed. The present method is very efficient with simple work up gives the products in good to excellent yield. The reaction is carried out using CHCl3 as solvent at room temperature. It is anticipated that the present newly developed method will open a gateway for the chemist to prepare the chemo as well as region-selective acetophenones. [ABSTRACT FROM AUTHOR]

• Novel Ni(II) and Fe(II) tetra substituted metallophthalocyanines by MW irradiation. • Nickel and iron phthalocyanines as a catalyst for transfer hydrogenation of ketones. • Ni2 was a remarkable catalyst for reduction of acetophenone derivatives, (2 h, 1 mmol% catalyst, 99 % conversion). • The phthalocyanine complexes act as competent auxiliaries in catalysis. Hydrogen transfer reduction methods are attracting increasing attention from synthetic chemists in view of their operational simplicity. Therefore, the novel Ni(II) and Fe(II) tetra substituted metallophthalocyanines containing resorcinol and guaiacol groups were synthesized using microwave irradiation and characterized via elemental analysis, UV-Vis and FT-IR spectroscopy, and TGA. The comparison of the catalytic features of phthalocyanine based on metals is discussed in detail. These phthalocyanine-complexes were tested in transfer hydrogenation (TH) of ketones in the existence of KOH, utilizing 2-propanol as a hydrogen source. Examination of different carbonyl substrates revealed that Nickel (II) phthalocyanine, (Ni2) complex was a remarkable catalyst for the catalytic reduction of acetophenones (1.0 mol % of catalyst, 99 % conversion). Furthermore, we have discovered that the catalytic characteristics of this class of molecules are significantly influenced by both steric and electronic variables. [Display omitted] [ABSTRACT FROM AUTHOR]

• Six novel complexes of tetra substituted metallophthalocyanines (Ni, Co, and Cu). • The catalytic transfer hydrogenation of various ketones was discussed. • The copper complexes were found to be catalysts for the TH of ketone. • Activity and structure are compared to analogous metallophthalocyanines complexes. • Catalysts are air stable, earth abundant, and inexpensive. In this study, tetra substituted metallophthalocyanines (M : Ni, Zn, Co, and Cu) containing imine and azo groups were synthesized using microwave irradiation. The structures of all complexes have been totally characterized via 1HNMR , 13CNMR , TGA/DTA, LC-MS/MS, elemental analysis, UV–Vis, FT-IR spectroscopy. The comparison of the catalytic features of phthalocyanine based on metals is also discussed briefly. These phthalocyanine-complexes were also used in the transfer hydrogenation (TH) of acetophenone derivatives in the existence of KOH, utilizing iso PrOH as a hydrogen source. Acetophenone compounds determined a TH of up to 99 % conversion. Copper phthalocyanines were first used as catalysts in transfer hydrogenation reactions. The Cu(II) complexes showed higher catalytic activity, converting up to 97 % at 1.0 mol% catalyst loading. Furthermore, we have discovered that the catalytic characteristics of this class of molecules are significantly influenced by both steric and electronic variables. A series of six novel complexes of tetra substituted metallophthalocyanines (Ni, Co, and Cu) containing imine and azo groups have been synthesized. The structures of all complexes have been totally characterized via 1HNMR , 13CNMR , TGA/DTA, LC-MS/MS, elemental analysis, UV–Vis, FT-IR spectroscopy. These phthalocyanine-complexes were also used in the transfer hydrogenation (TH) of acetophenone derivatives in the existence of KOH, utilizing iso PrOH as a hydrogen source. Acetophenone compounds determined a TH of up to 99 % conversion. Copper phthalocyanines were first used as catalysts in transfer hydrogenation reactions. The Cu complex (1c), bearing the –C = O substituent observed a mean yield of%97 at 7 h, the related Cu complex (2c), bearing the -C NPh substituent afforded of 99 % at 9 h. Furthermore, we have discovered that the catalytic characteristics of this class of molecules are significantly influenced by both steric and electronic variables. These comparable outcomes to other catalysts previously reported in the literature were superior to other featuring phthalocyanine complexes. [Display omitted] [ABSTRACT FROM AUTHOR]

Combined density functional theory and multireference configuration interaction methods including spin‐orbit coupling and spin‐vibronic interactions have been used to elucidate the photophysical pathways of benzophenone (BP), anthrone (A) and fluorenone (FL). Our results reveal that the slower S1(1nπ*) T1(3ππ*) passage of FL in the gas phase, as compared to BP and A, originates from the different electronic structures of the T1(3ππ*) states in these compounds and is not related to the planarity of the nuclear arrangement. Temperature effects on the rate constants of intersystem‐crossing (ISC), reverse ISC (rISC) and fluorescence have been investigated for FL in solvents of different polarity. Experimentally observed trends for rate constants are well reproduced. A nearly temperature‐ and solvent‐independent, slower down‐hill ISC component is attributed to the El‐Sayed‐forbidden S1(1ππ*) T1(3ππ*) transition in these environments. The faster El‐Sayed‐allowed S1(1ππ*) T2(3nπ*) ISC requires thermal activation in tetrahydrofuran and acetonitrile solution so that fluorescence may compete against triplet formation. In cyclohexane solution, S1(1ππ*) and T2(3nπ*) are nearly degenerate according to our calculations. Hence S1 T2 ISC and S1T2 rISC have similar rate constants. If T2 T1 internal conversion could be slowed down by deuteration or perfluorination, for example, FL‐derivatives might show delayed fluorescence. [ABSTRACT FROM AUTHOR]

Oxygenated aromatics are substantial secondary organic aerosol (SOA) precursors, such as benzyl alcohol and phenolic compounds. Aromatic ketone intermediate volatile organic compounds (IVOCs), as a subclass of oxygenated aromatics, were found in anthropogenic source emissions and may contribute to SOA formation. However, the SOA yields and formation pathways of aromatic ketone IVOCs remain unknown. In this study, the photooxidations of aromatic ketone IVOCs in the absence and presence of NO x were studied in an oxidation flow reactor, and the particle- and gas-phase oxidation products were measured. The maximum SOA yields of benzophenone and 1,2-diphenylethanone are 0.24 and 0.33-0.35, respectively, relatively high among oxygenated aromatics. The SOA yields in the presence of NO x are 2-3 times higher than those in the absence of NO x in the late stage of oxidation. As the photooxidation proceeds, H/C of SOA slightly increases with O/C, and a greater amount of more-oxidized ring-retaining products exists in the particle phase in the presence of NO x . Based on gas-phase products and possible reaction pathways, functionalization of benzoic acid via the phenolic pathway is favored in the presence of NO x . Thus, our study highlights the significant SOA formation from aromatic ketone IVOCs, especially in the presence of NO x during long-time photooxidation.

A simple and mild protocol for the direct deoxygenative coupling of aryl ketones with electron-rich (hetero)arenes to construct the C(sp2)−C(sp3) bond was achieved, which was mediated by TiCl 4 and by using ammonia borane (AB) as the reductant. This strategy provides a novel protocol for the synthesis of unsymmetrical diaryl- and triarylmethanes. [Display omitted] • An efficient protocol for the deoxygenative cross-coupling of aryl ketones with (hetero)arenes • Performed under mild conditions and could tolerate a variety of functional groups • A novel approach for the synthesis of unsymmetrical diaryl- and triarylmethanes. [ABSTRACT FROM AUTHOR]

The first heterogeneous catalyzed example for the direct synthesis of aromatic ketones via intermolecular carbopalladation of aliphatic nitriles and organoboron compounds was developed. This mild method proceeds with a supported palladium nanoparticles catalyst that could be reused and recycled five times. The fresh and used catalysts were characterized by XPS and TEM. The XPS analysis indicated that Pd0 was the active species for the reaction. This methodology provides a mild and cost-effective strategy for the efficient synthesis of ketones.

Abstract In the classical amidation between aromatic ketones and amines, 2.0 equivalents of amines are necessarily required to gain satisfying yields. The specific role of the amine in the direct amidation already puzzled us for a long time. In this work, we disclosed that the amine acts as both reactant and catalyst. Specifically, the determination of reaction intermediates revealed the full mechanism, based on which, the introduction of one equivalent base in the amidation is showcased here that a high yield (∼95 %) can be afforded using only 1.1 equiv. of amine.

A redox‐neutral, carboxylic acid promoted, [RuCl2(p‐cymene)]2 catalyzed, weakly coordinating, carbonyl assisted C−H allylation of aromatic ketones has been developed. The beneficial effect of carboxylic acid on the ruthenium catalyst towards C−H allylation of aromatic ketones has been further explored, using commercially available allyl acetate under mild reaction conditions. In addition, this method requires redox‐neutral reaction conditions, easily accessible starting materials, and shows excellent functional group compatibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • Perovskite was used for asymmetric electrocarboxylation of aromatic ketones. • 85% yield and 95% enantiomeric excess were obtained on La 0.7 Sr 0.3 Fe 0.8 Ni 0.2 O 3. • The high-performance mainly results from the increased concentration of O2– and Fe4+. • La 0.7 Sr 0.3 Fe 0.8 Ni 0.2 O 3 has enhanced intrinsic electrochemical performance. The perovskite oxides La 0.7 Sr 0.3 Fe 0.8 B 0.2 O 3 (B = Ti, Mn, Co, Ni and Cu) synthesized by sol–gel method were used as cathodes and tested in asymmetric electrocarboxylation of aromatic ketones. The study showed the La 0.7 Sr 0.3 Fe 0.8 Ni 0.2 O 3 (La7Sr3Fe8Ni2) catalyst is more active for asymmetric electrocarboxylation of acetophenone with 95% enantiomeric excess and 85% yield. The high electrocatalytic activity is attributed mainly to several factors, including the increased amount of lattice oxygen and Fe4+ species on the surface of La7Sr3Fe8Ni2, enhanced electrochemically active surface area and faster electron transfer. Furthermore, La7Sr3Fe8Ni2 also exhibited remarkable stability and reusability. [ABSTRACT FROM AUTHOR]

Asymmetric bioreduction of aromatic and heteroaromatic ketones is an important process in the production of precursors of biologically active molecules. In this study, the bioreduction of aromatic and hetero aromatic prochiral ketones into optically active alcohols was investigated using Lactobacillus senmaizukei as a whole-cell catalyst, since whole-cells are less expensive than pure enzymes. The study indicates enantioselective bioreduction of various substituted aromatic ketones (1–16) to the corresponding (R)-and (S)-chiral secondary alcohols (1a–16a) in low to excellent enantioselectivity (6–94%) with good yields (58–95%). In addition, heteroaromatic prochiral ketones 1-(pyridin-2-yl)ethanone (17) and 1-(furan-2-yl)ethanone (18) were reduced to (R)-17a and (R)-18a in enantiopure form with excellent conversion (>99%) and yields. These findings show that L. senmaizukei is a very important biocatalyst for asymmetric reduction of both 6-membered and 5-member heteroaromatic methyl ketones. This method promising a green synthesis for the synthesis of biologically important secondary chiral alcohols in an environmentally friendly and inexpensive process. [ABSTRACT FROM AUTHOR]

Visible‐light‐induced C−H aerobic oxidation is an important chemical transformation that can be applied for the synthesis of aromatic ketones. High‐cost catalysts and toxic solvents were generally needed in the present methodologies. Here, an efficient aqueous C−H aerobic oxidation protocol was reported. Through CeCl3‐mediated photocatalysis, a series of aromatic ketones were produced in moderate to excellent yields. With air as the oxidant, this reaction could be performed under mild conditions in water and demonstrated high activity and functional group tolerance. This method is economical, highly efficient, and environmentally friendly, and it will provide inspiration for the development of aqueous photochemical synthesis reactions. [ABSTRACT FROM AUTHOR]

A new and autocatalytic method was developed for Friedel‐Crafts acylation of arenes without additional catalyst and additive. A series of electron‐rich arenes underwent the acylation to give the targeted product in low to high yields by using aryl, alkyl and vinyl acyl chlorides as the acylating reagent, which gave an effective method for the preparation of diaryl ketones, alkyl aryl ketones and α,β‐unsaturated ketones. Preliminary mechanistic investigation suggested that the present acylation displayed an induction period and a sigmoid kinetic profile characteristic of autocatalytic systems, and the resulting H+ played a role of the catalyst. [ABSTRACT FROM AUTHOR]

Abstract Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 4‐phenylbut‐3‐en‐2‐one [07.024] and benzophenone [07.032] belonging to chemical group 21, when used as feed flavourings for all animal species. They are currently authorised for use as flavours in food. The use of 4‐phenyl‐3‐butene‐2‐one [07.024] is safe at the proposed normal use levels of 1 mg/kg complete feed for all animal species. Benzophenone [07.032] is safe at the proposed normal use levels of 1 mg/kg complete feed for all animal species except chicken for fattening, laying hens and piglets, for which the calculated safe concentration in feed is 0.5 mg/kg. No safety concern would arise for the consumer from the use of 4‐phenyl‐3‐butene‐2‐one [07.024] and benzophenone [07.032] as feed flavourings. In the absence of studies to assess the safety for the user, the FEEDAP Panel cannot conclude on the safety for users when handling the additives. The use of 4‐phenyl‐3‐butene‐2‐one [07.024] and benzophenone [07.032] in animal feed at the maximum safe use level in feed is also considered safe for the environment. Since the compounds under assessment are used in food as flavourings and their function in feed is essentially the same as that in food, no further demonstration of efficacy is necessary.

In the classical amidation between aromatic ketones and amines, 2.0 equivalents of amines are necessarily required to gain satisfying yields. The specific role of the amine in the direct amidation already puzzled us for a long time. In this work, we disclosed that the amine acts as both reactant and catalyst. Specifically, the determination of reaction intermediates revealed the full mechanism, based on which, the introduction of one equivalent base in the amidation is showcased here that a high yield (∼95 %) can be afforded using only 1.1 equiv. of amine. [ABSTRACT FROM AUTHOR]

Biocatalytic reduction is a very important field of research in synthetic organic chemistry. Herein, three different Lactic Acid Bacteria (LAB) strains were evaluated for their bioreduction potential using acetophenone as a model substrate. Among these strains, Lactobacillus kefiri P2 strain was determined as the best asymmetric reduction biocatalyst. Reaction optimization parameters such as reaction time, temperature, agitation speed and pH were systematically optimized using Lactobacillus kefiri P2 strain and model substrate acetophenone. Under these optimized reaction conditions, secondary chiral alcohols were obtained by bioreduction of various prochiral ketones with results up to 99% enantiomeric excess. In addition, the steric and electronic effects of substituents on enantioselectivity and conversion were evaluated. It has been shown that Lactobacillus kefiri P2 biocatalyst was an effective catalyst for asymmetric reduction. This method provides an environmentally friendly method for the synthesis of optically pure alcohols and an alternative approach to chemical catalysts. [ABSTRACT FROM AUTHOR]

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 4-phenylbut-3-en-2-one [07.024] and benzophenone [07.032] belonging to chemical group 21, when used as feed flavourings for all animal species. They are currently authorised for use as flavours in food. The use of 4-phenyl-3-butene-2-one [07.024] is safe at the proposed normal use levels of 1 mg/kg complete feed for all animal species. Benzophenone [07.032] is safe at the proposed normal use levels of 1 mg/kg complete feed for all animal species except chicken for fattening, laying hens and piglets, for which the calculated safe concentration in feed is 0.5 mg/kg. No safety concern would arise for the consumer from the use of 4-phenyl-3-butene-2-one [07.024] and benzophenone [07.032] as feed flavourings. In the absence of studies to assess the safety for the user, the FEEDAP Panel cannot conclude on the safety for users when handling the additives. The use of 4-phenyl-3-butene-2-one [07.024] and benzophenone [07.032] in animal feed at the maximum safe use level in feed is also considered safe for the environment. Since the compounds under assessment are used in food as flavourings and their function in feed is essentially the same as that in food, no further demonstration of efficacy is necessary. [ABSTRACT FROM AUTHOR]

Radicals in advanced oxidation processes (AOPs) degrade micropollutants during water and wastewater treatment, but the transformation of dissolved organic matter (DOM) may be equally important. Ketone moieties in DOM are known disinfection byproduct precursors, but ketones themselves are intermediates produced during AOPs. We found that aromatic alcohols in DOM underwent transformation to ketones by one-electron oxidants (using SO 4 •- as a representative), and the formed ketones significantly increased trichloromethane (CHCl 3 -FPs from aromatic ketones (Ar-CO-CH 3 -FPs from aromatic ketones (Ar-CO-CH 3 , average of 22 mol/mol) were 6-24 times of CHCl 3 -FPs from aromatic alcohols (Ar-CH(OH)-CH 3 , average of 0.85 mol/mol). At a typical SO 4 •- exposure of 7.0 × 10 -12 M·s, CHCl 3 -FPs from aromatic alcohol transformation increased by 24.8%-112% with an average increase of 53.4%. Notably, SO 4 •- oxidation of aliphatic alcohols resulted in minute changes in CHCl 3 -FPs due to their low reactivities with SO 4 •- (∼10 7 M -1 s -1 ). Other one-electron oxidants (Cl 2 •- , Br 2 •- ,and CO 3 •- ) are present in AOPs and also lead to aromatic alcohol-ketone transformations similar to SO 4 •- . This study highlights that subtle changes in DOM physicochemical properties due to one-electron oxidants can greatly affect the reactivity with free chlorine and the formation of chlorinated byproducts.

Abstract: As the most important method to prepare pharmaceutical and chemical intermediate aromatic ketones, Friedel-Crafts (F-C) acylation is used to seek a novel catalytic system which is imminently consistent with the concept of green chemistry. In this study, six deep eutectic solvents (DES) were synthesized for the Friedel-Crafts acylation reaction as a catalytic solvent. Among the six DES, choline chloride-zinc chloride ([ChCl][ZnCl2]2) proved to be the most competent candidate of electron-rich arenes with acylation reagent. It got the highest yield when 1.0 equivalent of [ChCl][ZnCl2]2 used with acyl halides at 70 °C. Recycled DES was reused directly without any extra process. After five cycles, the catalytic activity did not decrease significantly (80-85%). Finally, according to experimental validation, the possible mechanism of this reaction was considered.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Aerobic oxidation of organic compounds is receiving attention because molecular oxygen is an abundant, cheap and comparatively safe reagent. Several catalyst systems have been developed so far, but the priority is efficiency and the use of more sustainable reaction media. Here the synthesis of two bis-phosphinite-based palladium(II) complexes has been improved to overcome the lack of reproducibility from previous reports. The improvement relied on solvent modification, strictly inert conditions, monitoring by phosphorus-31 nuclear magnetic resonance, quick filtration and solvent removal steps. We show that both palladacycles are excellent palladium sources for the oxidation of secondary benzyl carbinols in the presence of molecular oxygen at atmospheric pressure. Oxidation of secondary benzyl carbinols carried out in the presence of a very small amount of such palladium complexes, of 0.01 mol%, provided the corresponding ketones in 35-91% yield. High turnover number values, of 3500-9100, substoichiometric amounts of base, of 10 mol%, and the environmentally friendly solvent polyethylene glycol 400 are additional advantages. [ABSTRACT FROM AUTHOR]

The reductive coupling of 1,3-dimethyhydantoin with benzophenones by TiCl 4 -Zn in THF gave 4-diarylmethyl-1 H -imidazol-2(3 H )-ones as four-electron reduced one-to-one coupled products and their dimers as two-to-two coupled products predominantly by controlling the reaction conditions. The reductive coupling of 5-alkyl-1,3-dimethyhydantoins with benzophenones produced 5-alkyl-4-diarylmethyl-1 H -imidazol-2(3 H )-ones as the sole products irrespective to the reaction conditions. On the other hand, the reductive coupling of 1,3-dimethyhydantoin with cyclic benzophenones selectively 4-arylhydroxymethyl-1 H -imidazol-2(3 H )-ones as two-electron reduced one-to-one coupled products and they were further reduced to 4-diarylmethyl-1 H -imidazol-2(3 H )-ones. [ABSTRACT FROM AUTHOR]

A simple approach for the formation of imines by condensation of ketones and anilines over heterogeneous catalyst (Hβ zeolite) has been successfully developed. The present catalytic system scope was explored for various aromatic ketones and anilines. Furthermore, Hβ zeolite can be easily separable and recycled several times (five times) without considerable loss of its catalytic activity. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Abstract: Herein, we report the synthesis and characterization of two ruthenophane (1) and ruthenium(II)‐π (2) complexes, and the results of their catalytic applications under different conditions. These complexes exhibited excellent air and moisture stability due to the existence of effective cation‐π interactions between the metal ion and the aromatic surface of the ligand. These complexes were tested and compared in the transfer hydrogenation of acetophenone in 2‐propanol. The ruthenophane complex 1 exhibited highest efficiency in the catalytic transfer hydrogenation reaction when compared to the complex 2. The better efficiency of the complex 1 can be ascribed to the steric and cation‐π interactions of the cyclophane ligands with the metal centre under reaction conditions. Using catalyst loading of ca. 2 mol%, the transfer hydrogenation of the aromatic ketones having different substituents was achieved. Notably, these complexes exhibited high selectivity for the aromatic ketones having electronegative substituents and showed highest efficiency of ca. 100% under moderate reaction conditions when compared to the literature known ruthenium catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of ferrocenyl hetaryl ketones was studied by quantum chemical methods. • UV–vis, IR and NMR characteristics of the ketones were calculated. • Various hetaryl groups were included to establish patterns in these characteristics. • The patterns were elucidated in terms of structural and electronic parameters. • Recommendations for suitable computational protocols were presented. Quantum chemical calculations have been carried out to elucidate the electronic structure as well as to draw structure-property relationships for a series of ferrocenyl hetaryl ketones by means of simulated NMR, IR and UV–vis spectra. In this series, the list of hetaryl groups included furan-2-yl, thiophen-2-yl, selenophen-2-yl, 1 H -pyrrol-2-yl and N -methylpyrrol-2-yl. Density functional theory was employed to determine the ground-state properties of the five ketones while their excited-state properties were modeled using a broad range of theoretical methods, namely from time-dependent density functional theory to multiconfigurational and multireference ab initio approaches. The patterns in the 13C and 17O chemical shifts of the carbonyl group were explained by the geometrical twist of hetaryl rings and by the electronic parameters corresponding to π -bonds conjugation and group hardness. Furthermore, the corresponding 13C and 17O shielding constants were analyzed in terms of both their dia/paramagnetic and Lewis/non-Lewis contributions within the framework of natural chemical shielding theory. The pattern in the vibrational frequency of the carbonyl bond was connected with changes in its bond length and bond order. It was established that the electronic absorption spectra of the studied ketones are largely characterized by low-intensity d → π * transitions in the visible region and the dominant high-intensity π → π * transition in the UV region. Finally, the theoretical methods best suited for modeling the excited-state properties of such ketones were designated. [ABSTRACT FROM AUTHOR]

Boron complexesBL1andBL2were prepared from O-donor ligands, 2,2′-(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(methane-1-yl-1-ylidene)diphenol (L1) and 2,2′-(propane-1,3-diylbis(azan-1-yl-1-ylidene))bis(methane-1-yl-1-ylidene)diphenol (L2). The complexes were fully characterized by1H and13C NMR, LC-MS/MS, TGA/DTA, UV-Vis, elemental analysis, SEM, and FTIR. The transfer hydrogenation of acetophenone derivatives was investigated by the boron complexes in the presence ofisoPrOH, as the hydrogen source, under basic condition with NaOH. The results showed that the boron complexes were promising catalytic precursors for transfer hydrogenation of aromatic ketones in 0.1 MisoPrOH solution (up to 99%). Both steric and electronic factors of this class of molecules had a significant impact on the catalytic properties. [ABSTRACT FROM PUBLISHER]

The electroreductive intermolecular coupling of aromatic ketones and aldehydes with α,β-unsaturated esters in the presence of TMSCl gave the adducts as γ-trimethylsiloxy esters. The detrimethylsilylation of the adducts with TBAF afforded 5-aryl substituted γ-butyrolactones. The electroreductive coupling of N -(4-methoxyphenyl)-1-arylmethaneimines with methyl acrylate in the presence of TMSCl gave the adducts as methyl 4-aryl-4-((4-methoxyphenyl)amino)butanoates. The adducts were transformed to 5-aryl-γ-butyrolactams by cyclization with NaH and subsequent oxidation with CAN. (±)-Norcotinine was prepared from nicotinaldehyde by this method. The electroreductive coupling of aromatic ketones and aldimines with acrylonitrile in the presence of TMSCl gave 4-aryl-4-(trimethylsiloxy)butanenitriles and 4-aryl-4-((4-methoxyphenyl)amino)butanenitriles, respectively. [ABSTRACT FROM AUTHOR]

The first enantioselective conjugate additions of problematic aromatic ketones and acetone to nitrodienynes have been achieved by employing a chiral multifunctional primary amine catalyst recently developed by us. The reactions took place in a 1,4-manner. Furthermore, by utilizing the resulting chiral functionalized 1,3-enynes as a starting point, we have developed unprecedented p-toluenesulfonic acid-catalyzed tandem annulations, which allow the efficient and selective construction of various synthetically useful cyclic 1,5-diketones (R=Ar) and dienones (R=Me). [ABSTRACT FROM AUTHOR]

The Brønsted-acidic ionic liquid 1-methyl-3-(4-sulfobutyl)imidazolium triflate [BMIM(SO3H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into α-halo and α,α-dihaloketones, depending on the quantity of NXS used. Ketones with activated aromatic rings were selectively halogenated, however in some cases mixtures of α-halogenated ketone and ring-halogenated ketones were obtained. Activated aromatics were regioselectively ring halogenated to give mono- and dihalo-substituted products. The [BMIM(SO3H)][OTf] ionic liquid (IL-A) was successfully reused eight times in a representative monohalogenation reaction with no noticeable decrease in efficiency. An effective halogenation scale-up in this IL is also presented. The reactivity trend and the observed chemo- and regioselectiivities point to an ET process in these IL-promoted halofunctionalization reactions.