- Catalytic hydrosilylation of carbonyl compounds by hydrido thiophenolato iron(II) complexes
-
The hydrosilylation of aldehydes and ketones under mild conditions with hydrido thiophenolato iron(II) complexes [cis–Fe(H)(SAr)(PMe3)4] (1–4) as catalysts is reported using (EtO)3SiH as an efficient reducing agent in the yields up to 95%. Among them complex 1 is the best catalyst. Complex 1 could also be used as catalyst to reduce the α,β-unsaturated carbonyl compounds selectively to the α,β-unsaturated alcohols in high yields.
- Xue, Benjing,Sun, Hongjian,Niu, Qingfen,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
-
-
Read Online
- Chemoselective protection of hydroxyl groups and deprotection of silyl ethers
-
Trimethylsilylation of alcohols and phenols is carried out using hexamethyldisilazane and LiClO4 under microwave irradiation and neutral conditions. The deprotection of silyl ethers is carried out similarly using natural kaolinitic clay and a few drops of water.
- Bandgar,Kasture
-
-
Read Online
- Zn(BH4)2/ultrasonic irradiation: An efficient system for reduction of carbonyl compounds to their corresponding alcohols
-
Zn(BH4)2 under ultrasonic irradiation is an efficient reducing system in CH3CN. This system reduces a variety of carbonyl compounds to their corresponding alcohols at room temperature in high to excellent yields of the products. Also, a,b-unsaturated aldehydes and ketones was regioselectively reduced to the corresponding allylic alcohols.
- Fanari, Siamak,Setamdideh, Davood
-
-
Read Online
- Unexpected course of Wittig reaction when using cinnamyl aldehyde as a substrate
-
When trans-cinnamyl aldehyde was used as a substrate of the Wittig reaction, instead of the olefination product, formation of four products with (E)-1,3-diphenylprop-2-en-1-ol and cinnamyl alcohol was observed being quite unexpected ones. The possible mechanism of this unusual reaction has been considered.
- Szymczyk, Monika
-
-
Read Online
- Conversion of alkyl halides into the corresponding alcohols under mild reaction conditions
-
Reaction of primary, cyclopentyl, allyl and arylmethyl halides, but not an acyclic secondary halide or a tertiary halide, in acetone or tetrahydrofuran with the formate form of a commercial anion exchange resin gave formate esters in good yields. The formates were hydrolysed efficiently to the corresponding alcohols by a brief treatment with hydrochloric acid. Reaction of primary alkyl bromides or iodides, secondary alkyl bromides, cinnamyl and arylmethyl halides in tetrahydropyran or 1,4-dioxane with the bicarbonate form of the same anion-exchange resin gave the corresponding alcohols directly in good yields. This latter reaction can be carried out successfully in the presence of ester or amide groups.
- Ruddick, Clare L.,Hodge, Philip,Houghton, Mark P.
-
-
Read Online
- Reduction of carbonyl compounds to the corresponding alcohols with isopropanol on dehydrated alumina under microwave irradiation
-
The reduction of different types of aldehydes and ketones were performed in the presence of isopropylalcohol (as solvent and hydride source) under microwave irradiation. It is proved that dehydrated Woelm chromatographic alumina supported KOH catalyses these transformations. Regioselectivity was observed in the reduction of cinnamaldehyde and chemoselectivity was observed in the reduction of carbonyl in the presence of nitro group.
- Kazemi,Kiasat
-
-
Read Online
- Exclusive 1,2-reduction of functionalised conjugated aldehydes with sodium triacetoxyborohydride
-
Functionalised α,β-unsaturated aldehydes were exclusively reduced to allylic alcohols with sodium-triacetoxyborohydride. Neither saturated alcohol nor saturated aldehydes are obtained. Conjugated ketones are not reduced.
- Singh, Jasvinder,Sharma, Munisha,Kaur, Irvinder,Kad, Goverdhan L.
-
-
Read Online
- Pyrococcus furiosus-mediated reduction of conjugated carboxylic acids: Towards using syngas as reductant
-
Pyrococcus furiosus catalyzes the reduction of carboxylic acids to their corresponding alcohols. In addition to hydrogen also carbon monoxide can be used as stoichiometric reductant, paving the way to cheap syngas to promote biocatalytic acid reduction. The enzymes responsible for coupling CO-oxidation to acid reduction are currently unknown but may represent an unprecedented enzyme class. Furthermore, enoate reductase-like activity has been detected in P. furiosus while lacking 'classical' enoate reductases.
- Ni, Yan,Hagedoorn, Peter-Leon,Xu, Jian-He,Arends, Isabel W.C.E.,Hollmann, Frank
-
-
Read Online
- Core-shell AgNP@CeO2 nanocomposite catalyst for highly chemoselective reductions of unsaturated aldehydes
-
Selective silver: A core-shell AgNP-CeO2 nanocomposite (AgNP@CeO2) acted as an effective catalyst for the chemoselective reductions of unsaturated aldehydes to unsaturated alcohols with H2 (see figure). Maximizing the AgNP-CeO2 interaction successfully induced the heterolytic cleavage of H2, resulting in highly chemoselective reductions. Furthermore, a highly dispersed AgNP@CeO2 system was also developed that exhibited a higher activity than the original AgNP@CeO2. Copyright
- Mitsudome, Takato,Matoba, Motoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
-
-
Read Online
- SELECTIVITY IN THE ACID CATALYSED REDUCTION OF CARBONYL COMPOUNDS TO ALCOHOLS BY BIS(TRIPHENYLPHOSPHINE)COPPER(I) TETRAHYDROBORATE: REDUCTION OF ALDEHYDES IN THE PRESENCE OF KETONES
-
Bis(triphenylphosphine)copper(I) tetrahydroborate reduces carbonyl compounds to alcohols in the presence of acid catalysts in excellent yields with high stereoselectivity; α,β-unsaturated aldehydes are reduced regioselectively.In a mixture of an aldehyde and a ketone, an aldehyde may be reduced preferentially.
- Fleet, G.W.J.,Harding, P.J.C.
-
-
Read Online
- Pinacol coupling of aromatic aldehydes and ketones using TiCl 3-Al-EtOH under ultrasound irradiation
-
Titanium trichloride in EtOH can be reduced by Al to the corresponding low-valent titanium complexes. This can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 40-82% yields within 30-90 min at r.t. under ultrasound irradiation.
- Li, Ji-Tai,Lin, Zhi-Ping,Qi, Na,Li, Tong-Shuang
-
-
Read Online
- A highly efficient Cu/AlOOH catalyst obtained by in situ reduction: Catalytic transfer hydrogenation of ML into Γ-GVL
-
Catalytic transfer hydrogenation (CTH) of carbonyl compounds is considered as one of the most promising processes in the synthesis of fuels and chemicals. In this work, we propose a one-step strategy for catalyst preparation and CTH. Using the strategy, the production of γ-valerolactone (γ-GVL) was performed with isopropanol (2-PrOH) as solvent over in situ reduced nano-Cu/AlOOH catalyst from Cu2(OH)2CO3/AlOOH and the optimal reaction conditions for γ-GVL are 180 °C for 5 h using the in situ reduced catalyst with Cu/Al molar ratio 3/1 (90.51% yields of γ-GVL). Furthermore, it has been confirmed by different characterization methods (such as: SEM, TEM, XPS, etc.) that the catalyst is heterogeneous and exhibits high catalytic activity and stability which is attributed to the stability of the zero-valent copper in the catalyst and the nanosized particles of the catalyst. In addition, the catalysts also show general applicability to other carbonyl compounds.
- Ma, Mingwei,Liu, Hui,Cao, Jingjie,Hou, Pan,Huang, Jiahui,Xu, Xingliang,Yue, Huijuan,Tian, Ge,Feng, Shouhua
-
-
Read Online
- A SIMPLE PROCEDURE FOR THE SYNTHESIS OF THREE-CARBON HOMOLOGATED BORONATE ESTERS AND TERMINAL ALKENES VIA NUCLEOPHILIC DISPLACEMENT IN α-HALOALLYLBORONATE ESTER
-
The transfer reactions of α-haloallylboronate ester 1 with representative organolithium and Grignard reagents provide α-alkyl- or α-aryl-substituted allylboronate esters, readily converted into three-carbon homologated boronate esters and terminal alkenes.
- Brown, Herbert C.,Rangaishenvi, Milind V.
-
-
Read Online
- Ultrasonic-promoted selective reduction of aldehydes vs. ketones by NaBH4/PhCO2Na/H2O
-
In this study, we have investigated the selective reduction of aldehydes vs. ketones by NaBH4/PhCO2Na/H2O system under ultrasound irradiation. NaBH4 (1.25 equivalents) and PhCO2Na (2 equivalents) is optimized conditions for reduce a variety of aldehydes (1 mmol) in the presence of ketones (1 mmol) to their corresponding alcohols in water as green solvent in high to excellent yields of the product (90-95%). A benzoate-borane complex [PhCO2-H3B]Na is possibly the active reductant in the reaction mixture.
- Mirtaghizadeh, Mina,Setamdideh, Davood
-
-
Read Online
- Cofactor recycling for selective enzymatic biotransformation of cinnamaldehyde to cinnamyl alcohol
-
The enzymatic, selective hydrogenation of cinnamaldehyde to cinnamyl alcohol is reported here. Yeast alcohol dehydrogenase was used in a substrate-coupled process with cofactor recycling. Both 100% selectivity and aldehyde conversion were achieved within
- Zucca, Paolo,Littarru, Maria,Rescigno, Antonio,Sanjust, Enrico
-
-
Read Online
- Preparation and Some Reactions of Allylic Indium Reagents
-
A variety of allylic indium sesquihalides were readily prepared by the reaction of indium powder with allylic halides in DMF at room temperature.Protonation of the allylindium reagents proceeded regiospecifically at the γ-position of the allylic group to give 1-propenes.A facile transformation of α-pinene to β-pinene was achieved via a myrtenylindium intermediate.Oxygenation of the allylic indium reagents gave mixtures of allylic alcohol isomers in moderate yields.The coupling of the allylindium reagents with cyclic imides gave diverse products depending on the structures of the substrates and the reagents.Stannylation with tributylchlorostannane occurred exclusively at the α-carbon, yielding allyltributylstannanes; E,Z isomerization of the allylic double bond depended largely upon the substitution pattern on the allylic moiety.
- Araki, Shuki,Shimizu, Toshio,Johar, Perminder S.,Jin, Shun-Ji,Butsugan, Yasuo
-
-
Read Online
- Poly(1,4-butyl-bis-vinylpyridinium) borohydride as a new stable and efficient reducing agent in organic synthesis
-
The unstable sodium borohydride is stabilized on modified poly(4-vinylpyridinium), and it is used as an efficient and regenerable polymer-supported borohydride reagent for the reduction of a variety of carbonyl compounds, such as aldehydes, ketones, α,β-unsaturated carbonyl compounds, α-diketones and acyloins, in good to excellent yields.
- Khaligh, Nader Ghaffari
-
-
Read Online
- Reduction of aldehydes catalyzed by oxo-rhenium(V) complexes containing heterocyclic ligands
-
This work describes the catalytic activity of several oxo-rhenium complexes containing the heterocyclic ligands 2-(2-hydroxy-5-methylphenyl)benzotriazole (Hhmpbta), 2-(2-hydroxyphenyl)benzothiazole (Hhpbt), 2-(2-hydroxyphenyl)benzoxazole (Hhpbo), 2-(2-hydroxyphenyl)-1H-benzimidazole (Hhpbi), isoquinoline-1-carboxylic acid (iqcH), and 4-methoxy-2-quinolinecarboxylic acid (mqcH) in the reduction of 4-nitrobenzaldehyde using phenylsilane as reducing agent. In general, all of the catalysts tested gave good to excellent yields of the 4-nitrobenzyl alcohol. Although, the best result was obtained with the catalytic system PhSiH3/[ReOBr2(hmpbta)(PPh3)] (5 mol %). This system was also applied to the reduction of a large variety of aldehydes, producing the corresponding primary alcohols in good to excellent yields and good chemoselectivity.
- Bernando, Joana R.,Florindo, Pedro R.,Wolff, Mariusz,Machura, Barbara,Fernandes, Ana C.
-
-
Read Online
- Quaternized amino functionalized cross-linked polyacrylamide as a new solid - Liquid phase transfer catalyst in reduction of carbonyl compounds with NaBH4
-
Poly[N-(2-aminoethyl)acrylamido]trimethyl ammonium chloride resin was developed as a new polymeric phase transfer catalyst. This quaternized polyacrylamide catalyzed the chemoselective reduction of aldehydes and ketones by NaBH4 to give corresponding alcohols in high yields under mild conditions.
- Tamami, Bahman,Mahdavi, Hossein
-
-
Read Online
- Metal-free catalytic reduction of aldehydes, ketones, aldimines, and ketimines
-
The metal-free combination of catalytic amounts of PPh3, B(C6F5)3, and PhSiH3 can efficiently hydrosilylate aldehydes, ketones, aldimines and ketimines to afford the corresponding reduction products in good yields.
- Matsuoka, Hiroaki,Kondo, Kazuhiro
-
-
Read Online
- Promotion of Sn on the Pd/AC catalyst for the selective hydrogenation of cinnamaldehyde
-
The effect of Sn on the Pd/AC catalysts for the selective hydrogenation of cinnamaldehyde (CALD) was investigated. TEM, EDX, XRD and XPS have been employed to characterize Pd-Sn/AC. 80% cinnamyl alcohol (COL) selectivity can be obtained at 96% CALD conversion, even 100% selectivity can be achieved at 3% conversion. The PdSn type alloy is responsible for the enhancement of unsaturated alcohol (UA) selectivity, as confirmed by XRD and EDX. XPS technique confirmed that the promoting effect of Sn was related to Pd-Sn interaction. The favorable adsorption of C = O bond on the PdSn has been supported by means of density functional theory.
- Zhao, Jia,Xu, Xiaoliang,Li, Xiaonian,Wang, Jianguo
-
-
Read Online
- Mild reduction of carboxylic acids to alcohols using cyanuric chloride and sodium borohydride
-
Several carboxylic acids, including N-Boc, N-Cbz and N-Fmoc amino acids were reduced to the corresponding alcohols by activation of the carboxy function with cyanuric chloride and N-methylmorpholine followed by reduction with aqueous sodium borohydride.
- Falorni, Massimo,Porcheddu, Andrea,Taddei, Maurizio
-
-
Read Online
- Cationic [2,6-Bis(2′-oxazolinyl)phenyl]palladium(II) Complexes: Catalysts for the Asymmetric Michael Reaction
-
Reaction of 1,3-dicyanobenzene with β-amino alcohols (S)-H2NCHRCH2OH (R = iPr, iBu, tBu, CH2Cy, CH2Ph) and (R)-H2NCHPhCH2OH gave new 1,3-bis(2′-oxazolinyl)benzenes (30-51%). These, together with 1,3-bis(4′,4′-dimethyl-2′-oxazolinyl)benzene, were treated with LDA/TMEDA followed by the addition of PdBr2(1,5-COD) to give [2,6-bis(2′-oxazolinyl)phenyl]-palladium(II) bromide complexes (21-41%). In two cases no complexes were obtained (R = Ph, CH2Ph) due to ring opening of the oxazolines by LDA/TMEDA. Treatment of the palladium complexes with AgBF4, AgOTf, or AgSbF6 in wet CH2Cl2 provided a series of cationic [2,6-bis(2′-oxazolinyl)phenyl]palladium complexes (28-87%) containing water coordinated to palladium, as established by an X-ray crystal structure analysis of (S,S)-[2,6-bis(4′-isopropyl-2′-oxazolinyl)phenyl]aquopalladium(II) trifluoromethanesulfonate. All of the cationic complexes proved to be efficient catalysts for the Michael reaction between α-cyanocarboxylates and methyl vinyl ketone and between acrylonitrile and activated Michael donors. Selectivities of up to 34% ee were obtained for the formation of (R)-ethyl 2-cyano-2-methyl-5-oxohexanoate.
- Stark, Mark A.,Jones, Geraint,Richards, Christopher J.
-
-
Read Online
- Photodeoxygenation of dibenzothiophene sulfoxide: Evidence for a unimolecular S-O cleavage mechanism
-
Photolysis of dibenzothiophene sulfoxide results in the formation of dibenzothiophene and oxidized solvent. Though quantum yields are low, chemical yields of the sulfide are quite high. Yields of the oxidized solvents can also be high. Typical products are phenol from benzene, cyclohexanol, and cyclohexene from cyclohexane and 2-cyclohexenol and epoxycyclohexane from cyclohexene. A number of experiments designed to elucidate the mechanism of the hydroxylation were carried out, including measurements of quantum yields as a function of concentration, solvent, quenchers, and excitation wavelength. These data are inconsistent with a mechanism involving a sulfoxide dimer, which also does not properly account for the solvent oxidations. It is suggested hbat the active oxidizing agent may be atomic oxygen O(3P) or a closely related noncovalent complex, based on the nature of the oxidation chemistry, comparison to known rate constants for O(3P) reactivity, and the quantum yield data.
- Gregory, Daniel D.,Wan, Zehong,Jenks, William S.
-
-
Read Online
- Pyridine: N-oxide promoted hydrosilylation of carbonyl compounds catalyzed by [PSiP]-pincer iron hydrides
-
Five [PSiP]-pincer iron hydrides 1-5, [(2-Ph2PC6H4)2HSiFe(H)(PMe3)2 (1), (2-Ph2PC6H4)2MeSiFe(H)(PMe3)2 (2), (2-Ph2PC6H4)2PhSiFe(H)(PMe3)2 (3), (2-(iPr)2PC6H4)2HSiFe(H)(PMe3) (4), and (2-(iPr)2PC6H4)2MeSiFe(H)(PMe3)2 (5)], were used as catalysts to study the effects of pyridine N-oxide and the electronic properties of [PSiP]-ligands on the catalytic hydrosilylation of carbonyl compounds. It was proved for the first time that this catalytic process could be promoted with pyridine N-oxide as the initiator at 30 °C because the addition of pyridine N-oxide is beneficial for the formation of an unsaturated hydrido iron complex, which is the key intermediate in the catalytic mechanism. Complex 4 as the best catalyst shows excellent catalytic performance. Among the five complexes, complex 3 was new and the molecular structure of complex 3 was determined by single crystal X-ray diffraction. A proposed mechanism was discussed.
- Chang, Guoliang,Fenske, Dieter,Fuhr, Olaf,Li, Xiaoyan,Sun, Hongjian,Xie, Shangqing,Yang, Wenjing,Zhang, Peng
-
-
Read Online
- Selective Reductions: 33. Potassium Triisopropoxyborohydride as a Selective Reducing Agent in Organic Synthesis. Reaction with Selected Organic Compounds Containing Representative Functional Groups
-
The approximate rate and stoichiometry of the reaction of excess pure potassium triisopropoxyborohydride, KIPBH, with 56 selected compounds containing representative functional groups under standardized conditions (tetrahydrofuran, 0 deg C) was examined in order to define the characteristics of the reagent for selective reductions.Primary, secondary, and tertiary alcohols evolve hydrogen partially, even after a long period of time.Phenol also generates partial hydrogen, and the reactions of those amines and thiols studied with the reagent are very slow.Aldehydes andketones are reduced rapidly and quantitatively to give the corresponding alcohols.Unlike sodium and potassium borohydrides, KIPBH is very stereoselective. 2-Methylcyclohexanone can be reduced to the correspondingly less stable isomer, cis-2-methylcyclohexanol, in a high ratio (91percent cis isomer).Cinnamaldehyde is rapidly reduced to cinnamylalcohol, and further reduction is very slow under these conditions.Anthraquinone is cleanly reduced to 9,10-dihydro-9,10-anthracenediol.Carboxylic acids liberate hydrogen only partially, and further reduction is very slow.Acid chlorides consume 1 equiv of hydride rapidly, but the corresponding aldehydes do not form.Esters are almost inert toward the reagent. γ-Butyrolactone and phthalide are reduced only slowly.Epoxides are inert toward the reagent.Primary aliphatic amides evolve hydrogen slowly and primary aromatic amides evolve 1 equiv of hydrogen, but no significant reduction occurs.Tertiary amides and nitriles are inert toward the reagent.Of the nitrogen compounds studied, nitrobenzene is partially reduced after 48h, while azobenzene and azoxybenzene are inert.Partial reduction ofcyclohexanone oxime is observed, while phenyl isocyanate, pyridine, and pyridine N-oxide are inert under these conditions.Di n-butyl disulfide and diphenyl disulfide are reduced rapidly and quantitatively to the corresponding mercaptans with partial hydrogen evolution.Other sulfur compounds studied, such as p-tolyl methyl sulfide, diphenylsulfone, methanesulfonic acid, and p-toluenesulfonic acid, are inert toward the reagent.Only partial reduction of cyclohexyl tosylate is observed.Potassium triisopropoxyborohydride is a valuable reagent in boron chemistry.Thus, it transfers 1 equiv of hydride to dialkylhaloboranes, and the resulting dialkylborane can be transformed to a mixed trialkylborane, providing a potential route to mixed trialkylcarbinols or unsymmetrical ketones.The reagent rapidly transfers hydride to even severely hindered trialkylboranes, providing a simple synthetic route to these useful reagents.Finally, it readily converts 2-bromo-trans-vinylboronic esters to the cis-vinylboronic esters, providing a convenient synthetic route to these derivatives.
- Brown, Herbert C.,Cha, Jin Soon,Nazer, Behrooz,Kim, Suk-Choong,Krishnamurthy, Sundaram
-
-
Read Online
- Hydrogenation of α,β-Unsaturated Aldehydes and Ketones to the Unsaturated Alcohols catalysed by Hydridoiridium Phosphine Complexes
-
Unusual selective hydrogenation of cinnamaldehyde and benzylideneacetone to the corresponding unsaturated alcohols is catalysed by (+) complexes in toluene; use of a chiral phosphine gives a 7.4percent enantiomeric excess of (S)-(-)-1-phenylbut-1-en-3-ol.
- Farnetti, E.,Pesce, M.,Kaspar, J.,Spogliarich, R.,Graziani, M.
-
-
Read Online
- Phosphine- and ammonium-functionalized ordered mesoporous carbons as supports for cluster-derived metal nanoparticles
-
An ordered mesoporous carbon (OMC) was functionalized with ammonium or chelating phosphine ligands. In both cases, the functionalization procedure started by oxidation by nitric acid treatment, followed by activation of surface carboxylic acid groups with
- Vidick,Leonard,Poleunis,Delcorte,Devillers,Hermans
-
-
Read Online
- Iron-Catalyzed Allylic Amination Directly from Allylic Alcohols
-
Allylic amination, directly from alcohols, has been demonstrated without any Lewis acid activators using an efficient and regiospecific molecular iron catalyst. Various amines and alcohols were employed and the reaction proceeded through the oxidation/reduction (redox) pathway. A direct one-step synthesis of common drugs, such as cinnarizine and nafetifine, was exhibited from cinnamyl alcohol that produced water as side product. The iron way! A direct amination of allylic alcohols has been demonstrated without the need of Lewis acid activators using an efficient and regiospecific molecular iron catalyst. A range of amines and alcohols were tolerated, and the reaction was found to procced through an oxidation/reduction (redox) pathway (see scheme).
- Emayavaramban, Balakumar,Roy, Moumita,Sundararaju, Basker
-
-
Read Online
- Simple and efficient 1,3-isomerization of allylic alcohols using a supported monomeric vanadium-oxide catalyst
-
Promotion by group high five: Silica-supported monomeric vanadium-oxide promoted the isomerization of various allylic alcohols, including under scaled-up and solvent-free reaction conditions. This catalyst also exhibited high reusability with no drop in activity.
- Mitsudome, Takato,Sueoka, Shoichiro,Ikeda, Satoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
-
-
Read Online
- Polymer Supported Zirconium Borohydride: a Stable, Efficient and Regenerable Reducing Agent
-
The unstable zirconium borohydride, Zr(BH4)4, is stabilized on polyvinylpyridine and used as a new, stable, efficient and regenerable polymer supported transition-metal borohydride reagent for reduction of a variety of carbonyl compounds.
- Tamami, Bahman,Goudarzian, Nouredin
-
-
Read Online
- Microwave assisted solid reaction: Reduction of esters to alcohols by potassium borohydride-lithium chloride
-
Esters can be successfully reduced to the corresponding alcohols with potassium borohydride/lithium chloride under microwave irradiation without solvent. The reactions are generally completed in 2-8 minutes, with the yields varying from 55% to 95%.
- Feng,Liu,Dai,Yang,Tu
-
-
Read Online
- Chemoselective transfer hydrogenation of carbonyl compounds catalyzed by macrocyclic nickel (II)complex
-
Macrocyclic Ni(II) complex, 1, catalyzes efficiently the chemoselective transfer reduction of carbonyl compounds in presence of propan-2-ol/KOH or HCO2H/HCO2NH4 as hydrogen donors to produce the corresponding alcohols in high yield.
- Phukan, Prodeep,Sudalai
-
-
Read Online
- Hydrosilylation of aldehydes and ketones catalyzed by an n-heterocyclic carbene-nickel hydride complex under mild onditions
-
Half-sandwich N-heterocyclic carbene (NHC)-nickel complexes of the general formula [NiACHTUNGTRENUNG(NHC)ClCp?] (Cp?= Cp, Cp*) efficiently catalyze the hydrosilylation of aldehydes and ketones at room temperature in the presence of a catalytic amount of sodium triethylborohydride and thus join the fairly exclusive club of well-defined nickel(II) catalyst precursors for the hydrosilylation of carbonyl functionalities. Of notable interest is the isolation of an intermediate nickel hydride complex that proved to be the real catalyst precursor.
- Bheeter, Linus P.,Henrion, Mickael,Brelot, Lydia,Darcel, Christophe,Chetcuti, Michael J.,Sortais, Jean-Baptiste,Ritleng, Vincent
-
-
Read Online
- Poly(n-butyl-4-vinylpyridinium) borohydride as a new stable and efficient reducing agent in organic synthesis
-
Sodium borohydride is stabilized on poly(n-butyl-4-vinylpyridinium) chloride, and it is used as an efficient and regenerable polymer-supported borohydride reagent for the reduction of a variety of carbonyl compounds, such as aldehydes, ketones, α,β-unsaturated carbonyl compounds, α-diketones, and acyloins.
- Khaligh, Nader Ghaffari,Ghasem-Abadi, Parisa Ghods,Mihankhah, Taraneh
-
-
Read Online
- A mild and chemoselective method for the deprotection of tert-butyldimethylsilyl (TBDMS) ethers using iron(III) tosylate as a catalyst
-
The most common method for the deprotection of TBDMS ethers utilizes stoichiometric amounts of tetrabutylammonium fluoride, n-Bu4N+F- (TBAF), which is highly corrosive and toxic. We have developed a mild and chemoselective method for the deprotection of TBDMS, TES, and TIPS ethers using iron(III) tosylate as a catalyst. Phenolic TBDMS ethers, TBDPS ethers and the BOC group are not affected under these conditions. Iron(III) tosylate is an inexpensive, commercially available, and non-corrosive reagent.
- Bothwell, Jason M.,Angeles, Veronica V.,Carolan, James P.,Olson, Margaret E.,Mohan, Ram S.
-
-
Read Online
- Regulating Hydrogenation Chemoselectivity of α,β-Unsaturated Aldehydes by Combination of Transfer and Catalytic Hydrogenation
-
Two hydrogenation mechanisms, transfer and catalytic hydrogenation, were combined to achieve higher regulation of hydrogenation chemoselectivity of cinnamyl aldehydes. Transfer hydrogenation with ammonia borane exclusively reduced C=O bonds to get cinnamyl alcohol, and Pt-loaded metal–organic layers efficiently hydrogenated C=C bonds to synthesize phenyl propanol with almost 100 % conversion rate. The hydrogenation could be performed under mild conditions without external high-pressure hydrogen and was applicable to various α,β-unsaturated aldehydes.
- Zhou, Yangyang,Li, Zihao,Liu, Yanbo,Huo, Jia,Chen, Chen,Li, Qiling,Niu, Songyang,Wang, Shuangyin
-
-
Read Online
- SELECTIVE REDUCTION OF ALDEHYDES BY A FORMIC ACID- TRIALKYLAMINE- RuCl2(PPh3)3 SYSTEM
-
In the presence of trialkylamine and formic acid, RuCl2(PPh3)3 selectively reduces aldehydes to the corresponding alkohols at room temperature.Other reducible groups are unaffected.
- Khai, Bui The,Arcelli, Antonio
-
-
Read Online
- Facile and chemoselective reduction of carboxylic acids into alcohols via sodium borohydride reduction of N-acylbenzotriazoles
-
Carboxylic acids are converted into corresponding alcohols by chemoselective reduction of their benzotriazole amides with sodium borohydride. Copyright Taylor & Francis, Inc.
- Singh, Kamal Nain,Kaur, Amarjit
-
-
Read Online
- A mild method for the deprotection of tetrahydropyranyl (THP) ethers catalyzed by iron(III) tosylate
-
A mild method for the deprotection of THP ethers catalyzed by iron(III) tosylate (2.0 mol %) in CH3OH has been developed. Iron(III) tosylate, Fe(OTs)3·6H2O, is a commercially available solid that is inexpensive, noncorrosive, and easy to handle. The room temperature reaction conditions make this method attractive for deprotection of a range of THP ethers.
- Bockman, Matthew R.,Angeles, Veronica V.,Martino, Julia M.,Vagadia, Purav P.,Mohan, Ram S.
-
-
Read Online
- Caro's acid supported on silica gel. Part V: A mild and selective reagent for conversion of trimethyl silyl ethers to the corresponding hydroxy compounds
-
Mild and efficient method for deprotection of silyl ethers to alcohols is described using Caro's acid supported on silica gel. Reactions are carried out in dichloromethane at room temperature and their parent hydroxy compounds obtained in good to excellent yields. Using this procedure, tetrahydropyranyl ethers (THP) remain intact during desilylation reaction.
- Lakouraj,Tajbakhsh,Khojasteh
-
-
Read Online
- BOROHYDRIDE REDUCING AGENT DERIVED FROM ANION EXCHANGE RESIN : SELECTIVE REDUCTION OF α, β-UNSATURATED CARBONYL COMPOUNDS.
-
Borohydride exchange resin (BER) exhibited selectivity in the reduction of α, β-unsaturated carbonyl compounds to the corresponding unsaturated alcohols.
- Sande, A. R.,Jagadale, M. H.,Mane, R. B.,Salunkhe, M. M.
-
-
Read Online
- New heterogeneous B(OEt)3-MCM-41 catalyst for preparation of α,β-unsaturated alcohols
-
Grafting of boron tri-ethoxide on mesoporous MCM-41 resulted in a highly active catalyst for the Meerwein-Ponndorf-Verley (MPV) reduction and the catalyst denoted as B(OEt)3-MCM-41. Chemoselective reduction of α,β-unsaturated aldehydes and ketones to the corresponding α,β-unsaturated alcohols was achieved by MPV reduction reaction using a new B(OEt)3-MCM-41 catalyst. The prepared new heterogeneous catalyst, B(OEt)3-MCM-41, was characterized in detail by using XRD, 29Si NMR-, 11B NMR-, 13C NMR-, and TEM, N2 adsorption, and ICP-OES. The results demonstrated the successful homogenous distribution of the B(OEt)3 on the MCM-41 support. The heterogeneous B(OEt)3-MCM-41 catalyst, in comparison with the homogeneous B(O i Pr)3 and B(OEt)3 catalysts, displayed similiar catalytic activity in the MPV reduction of α,β-unsaturated aldehydes and ketones with alcohols as reductants. Reduced reaction times and very high selectivities for the unsaturated alcohols were obtained with the heterogenous catalyst compared with the homogeneous catalysts. The B(OEt)3-MCM-41 catalyst was found to be encouraging, as is is recyclable up to six cycles without any significant loss in its catalytic activity.
- Uysal, Burcu,Oksal, Birsen S.
-
-
Read Online
- Tuning Cu Overvoltage for a Copper-Telluride System in Electrocatalytic Water Reduction and Feasible Feedstock Conversion: A New Approach
-
Highly efficient and earth-abundant elements capable of water reduction by electrocatalysis and are attractive for the sustainable generation of fuels. Among the earth-abundant metals, copper is one of the cheapest but often the most neglected choice for the hydrogen evolution reaction (HER) due to its high overvoltage. Herein, for the first time we have tuned the overpotential of copper by tellurizing it by two different methodologies, viz. hydrothermal and wet chemical methods, which form copper telluride nanochains and aggregates. The application of copper telluride as an electrocatalyst for the HER gave fruitful results in terms of both activity and stability. The hydrothermally synthesized catalyst Cu2-xTe/hyd shows a low overpotential (347 mV) at 10 mA cm-2 toward the HER. In addition, the catalyst showed a very low charge transfer resistance (Rct) of 24.4 ω and, as expected, Cu2-xTe/hyd exhibited a lower Tafel slope value of 188 mV/dec in comparison to Cu2-xTe/wet (280 mV/dec). A chronoamperometry study reveals the long-term stability of both catalysts even up to 12 h. The Faradaic efficiency of Cu2-xTe/hyd was calculated and found to be 95.06percent by using gas chromatographic (GC) studies. Moreover, with the idea of utilizing produced hydrogen (H2) from electrocatalysis, for the first time we have carried out feedstock conversion to platform chemicals in water under eco-friendly green conditions. We have chosen cinnamaldehyde, 2-hydroxy-1-phenylethanone, 4-(benzyloxy)benzaldehyde, and 2-(3-methoxyphenoxy)-1-phenylethanone (β-O-4) as model compounds for feedstock conversion by hydrogenation and/or hydrogenolysis reactions in aqueous medium using external hydrogen pressure. This protocol could also be scaled up for large-scale conversion and the catalyst is likely to find industrial application since it requires an inexpensive catalyst and an easily available, mild reducing agent. The robustness of the developed catalyst is proven by recyclability experiments and its possibility of use in real-life applications.
- Johny, Jinta Merlin,Karthick, Kannimuthu,Kumaravel, Sangeetha,Kundu, Subrata,Sankar, Selvasundarasekar Sam,Thiruvengetam, Prabaharan
-
-
Read Online
- Selective Deprotection of the Diphenylmethylsilyl (DPMS) Hydroxyl Protecting Group under Environmentally Responsible, Aqueous Conditions
-
Two new methods for selective deprotection of diphenylmethylsilyl (DPMS) ethers are described. Unmasking can be achieved with either catalytic amounts of perfluoro-1-butanesulfonyl fluoride (a SuFEx reagent) under mild, aqueous micellar conditions, or using stoichiometric amounts of 18-crown-6 ether in aqueous ethanol.
- Akporji, Nnamdi,Lieberman, Josh,Maser, Michael,Yoshimura, Masahiko,Boskovic, Zarko,Lipshutz, Bruce H.
-
-
Read Online
- Chemoselective reduction of carbonyl compounds to alcohols with co-doped ammonia borane
-
Chemoselective reduction of various carbonyl compounds to alcohols with Co-doped ammonia borane was investigated in the present work. It was observed that Co-doped ammonia borane exhibited much better performance than ammonia borane. The Co-based catalysts could be reused up to four times with a slight decrease in activity. Thus, a mild and efficient method for chemoselective reduction of carbonyl compounds with Co-doped ammonia borane was established. The Co-doped ammonia borane sample was characterized by electron paramagnetic resonance. Electron paramagnetic resonance characterization revealed that Co element in a partially reduced state.
- Huang, Pengmian,Tang, Wenjuan,Tan, Guishan,Zeng, Wenbin,Li, Yuanjian,Zhang, Qinghua,Chen
-
-
Read Online
- Reduction of carbonylic and carboxylic groups by plant cell cultures
-
The transformation of aliphatic and aromatic acids to their corresponding alcohols, involving two reductive steps, is difficult to perform biologically due to its low redox potential. For this reason, the reduction of nonactivated carboxylic acids has been described for only a limited number of substrates and confined to a few microbial groups (fungi, clostridia, and archea). Nine species of cultured plant cells were able to reduce cinnamic, hexanoic, and octanoic acids to the corresponding primary alcohols with yields ranging from 2 to 80% (w/w). Aldehyde was detected only for three species during the reduction of cinnamic acid, confirming that the second reductive step from aldehyde to alcohol is faster than the first, from acid to aldehyde. Lyophilized cells from some of the cultures were used in buffer and solvent-water systems to obtain the reduction of carbonylic (ethyl acetoacetate) and carboxylic (cinnamic and hexanoic acids) groups.
- Villa, Raffaella,Molinari, Francesco
-
-
Read Online
- Low-temperature reduction of bio-based cinnamaldehyde to α,β-(un)saturated alcohols enabled by a waste-derived catalyst
-
A waste eggshell-derived catalyst (CaO-900) was facilely prepared and exhibited high efficiency in selective hydrogenation of bio-based cinnamaldehyde (CAL) to cinnamyl alcohol (COL) with 97% yield at 30 °C. By simply adjusting reaction temperature and time, CAL could be completely converted to 3-phenylpropanol. The predominant catalytic performance of CaO-900 could be attributed to its high alkalinity and large specific surface area. In situ Raman and theoretical calculations indicated that the priority of hydrosilylation toward CAL played a crucial role in the control of product distribution. In addition, the CaO-900 catalyst showed good recyclability.
- Jian, Yumei,Li, Hu,Luo, Xiaoxiang
-
-
- Synthesis of aluminum doped MIL-100(Fe) compounds for the one-pot photocatalytic conversion of cinnamaldehyde and benzyl alcohol to the corresponding alcohol and aldehyde under anaerobic conditions
-
Fully utilizing the photogenerated electrons and holes in a photocatalytic process is a promising way to enhance catalytic efficiency and achieve atomic economy. Here, conjugated photocatalytic redox reactions, i.e. hydrogenation of cinnamaldehyde (CAL) t
- Guo, Binbin,Kang, Yueyue,Shi, Yingzhang,Wang, Zhiwen,Wu, Ling
-
p. 184 - 192
(2022/02/03)
-
- Platinum supported on nanosilica and fibrous nanosilica for hydrogenation reactions
-
Platinum nanoparticles supported on nanosilica (NP) and fibrous nanosilica (dendritic fibrous nano-spheres, DFNS) were prepared by direct grafting of the Pt precursor onto the silanol groups or via a polyethylenimine (PEI) linker. From the SEM and TEM images the average diameter of the nanosilica and fibrous nanosilica (DFNS), was determined to be 21.4 and 503 nm, respectively. While surface areas as measured by ASAP is 463.4 m2 g?1 for DFNS and 142.5 m2 g?1 for the nanosilica. For the four Pt containing catalysts (Pt/NP, Pt/DFNS, Pt/PEI/NP and Pt/PEI/DFNS), a Pt loading between 1.35 × 1017 and 8.46 × 1017 Pt atoms per gram support were determined. The PEI-containing catalyst gave higher Pt-loading than the direct anchoring of the Pt onto the silanol groups of the support. The catalysts were further characterised ATR FTIR and XPS. After oxidation of the pre-catalysts 85% of the Pt was in the oxide form. While after reduction, ca. 82% the Pt supported on DFNS was in the metallic form. Reduction of the Pt supported on NP, resulted in 100% of the Pt in the Pt0 oxidation state. These catalysts were tested for the hydrogenation of C[dbnd]C and/or C[dbnd]O bonds in cyclohexene, benzaldehyde and cinnamaldehyde. The % conversion and product distribution will be discussed in term of diameter, surface area and Pt-loading.
- Erasmus, E.,Xantini, Z.
-
-
- A Water/Toluene Biphasic Medium Improves Yields and Deuterium Incorporation into Alcohols in the Transfer Hydrogenation of Aldehydes
-
Deuterium labeling is an interesting process that leads to compounds of use in different fields. We describe the transfer hydrogenation of aldehydes and the selective C1 deuteration of the obtained alcohols in D2O, as the only deuterium source. Different aromatic, alkylic and α,β-unsaturated aldehydes were reduced in the presence of [RuCl(p-cymene)(dmbpy)]BF4, (dmbpy=4,4′-dimethyl-2,2′-bipyridine) as the pre-catalyst and HCO2Na/HCO2H as the hydrogen source. Moreover, furfural and glucose, were selectively reduced to the valuable alcohols, furfuryl alcohol and sorbitol. The processes were carried out in neat water or in a biphasic water/toluene system. The biphasic system allowed easy recycling, higher yields, and higher selective D incorporation (using D2O/toluene). The deuteration took place due to an efficient effective M–H/D+ exchange from D2O that allows the inversion of polarity of D+ (umpolung). DFT calculations that explain the catalytic behavior in water are also included.
- Ruiz-Casta?eda, Margarita,Santos, Lucía,Manzano, Blanca R.,Espino, Gustavo,Jalón, Félix A.
-
p. 1358 - 1372
(2021/03/16)
-
- Direct Heterogenization of the Ru-Macho Catalyst for the Chemoselective Hydrogenation of α,β-Unsaturated Carbonyl Compounds
-
In this study, a commercially available homogeneous pincer-type complex, Ru-Macho, was directly heterogenized via the Lewis acid-catalyzed Friedel-Crafts reaction using dichloromethane as the cross-linker to obtain a heterogeneous, pincer-type Ru porous organometallic polymer (Ru-Macho-POMP) with a high surface area. Notably, Ru-Macho-POMP was demonstrated to be an efficient heterogeneous catalyst for the chemoselective hydrogenation of α,β-unsaturated carbonyl compounds to their corresponding allylic alcohols using cinnamaldehyde as a model compound. The Ru-Macho-POMP catalyst showed a high turnover frequency (TOF = 920 h-1) and a high turnover number (TON = 2750), with high chemoselectivity (99%) and recyclability during the selective hydrogenation of α,β-unsaturated carbonyl compounds.
- Padmanaban, Sudakar,Gunasekar, Gunniya Hariyanandam,Yoon, Sungho
-
supporting information
p. 6881 - 6888
(2021/03/01)
-
- Synthesis method of 2-benzoxepin compound
-
The invention discloses a synthesis method of a 2-benzoxepin compound. The method comprises the following specific steps: under the protection of nitrogen, adding N-phenylseleno-phthalimide into a reactor, then adding anhydrous dichloromethane to dissolve the N-phenylseleno-phthalimide, then adding a 1-[(cinnamyl) methyl]-3, 4, 5-trimethoxybenzene compound, taking zinc chloride as a catalyst, reacting at room temperature, adding saturated sodium bicarbonate for quenching after the reaction is finished, extracting by dichloromethane, combining organic phases, drying by anhydrous magnesium sulfate, concentrating under reduced pressure, and performing silica gel rapid chromatographic purification by thin-layer chromatography silica gel to obtain the 2-benzoxepin compound. The method is simple in reaction operation, mild in reaction condition, relatively high in yield, environment-friendly and suitable for large-scale industrialized production.
- -
-
Paragraph 0045; 0049
(2021/05/29)
-
- Synthesis method of isochroman compound
-
The invention discloses a synthesis method of an isochroman compound, which comprises the following steps of adding dichloromethane and phosphorus tribromide into 3, 4, 5-trimethoxy benzyl alcohol, and reacting to obtain 1-bromomethyl-3, 4, 5-trimethoxy benzene, adding tetrahydrofuran, cinnamyl alcohol, sodium hydride and 1-bromomethyl-3, 4, 5-trimethoxybenzene into a reactor, and reacting to obtain 1-[(cinnamyl oxy)methyl]-3, 4, 5-trimethoxybenzene, adding cyanuric acid into a reactor containing a potassium hydroxide aqueous solution to react, dropwise adding a silver nitrate aqueous solution, and reacting to obtain silver isocyanurate, adding silver isocyanurate, phenyl selenium bromide and anhydrous dichloromethane into a reactor, and reacting to obtain N, N, N-triphenyl seleno isocyanurate, reacting N, N, N-triphenyl seleno isocyanurate, dichloromethane, boron trifluoride diethyl etherate and a 1-[(cinnamyl oxy)methyl]-3, 4, 5-trimethoxybenzene compound to obtain a target product. The method is simple in reaction operation, mild in reaction condition, relatively high in yield and environment-friendly.
- -
-
Paragraph 0046; 0050
(2021/05/15)
-
- Catalytic Asymmetric Allylic Substitution with Copper(I) Homoenolates Generated from Cyclopropanols
-
By using copper(I) homoenolates as nucleophiles, which are generated through the ring-opening of 1-substituted cyclopropane-1-ols, a catalytic asymmetric allylic substitution with allyl phosphates is achieved in high to excellent yields with high enantioselectivity. Both 1-substituted cyclopropane-1-ols and allylic phosphates enjoy broad substrate scopes. Remarkably, various functional groups, such as ether, ester, tosylate, imide, alcohol, nitro, and carbamate are well tolerated. Moreover, the present method is nicely extended to the asymmetric construction of quaternary carbon centers. Some control experiments argue against a radical-based reaction mechanism and a catalytic cycle based on a two-electron process is proposed. Finally, the synthetic utilities of the product are showcased by means of the transformations of the terminal olefin group and the ketone group.
- Shi, Chang-Yun,Yin, Liang,Zhang, Qi,Zhou, Si-Wei
-
supporting information
p. 26351 - 26356
(2021/11/09)
-
- Iridium-Catalyzed Regioselective Hydroalkynylation of Internal Alkenes Directed by an Oxime
-
We report here an iridium-catalyzed hydroalkynylation of allylic alcohols protected by an oxime group. Catalytic alkynylation occurs exclusively at the distal position of the alkene. This method generates γ-alkynyl alcohol oximes directly from internal alkenes and terminal alkynes. The oxime group can be readily removed to afford a free alcohol, thus providing an indirect route for the catalytic hydroalkynylation of allylic alcohols.
- Gao, Peng-Chao,Li, Bi-Jie,Wang, Zi-Xuan
-
supporting information
p. 9500 - 9504
(2021/12/14)
-
- Hydroboration Reaction and Mechanism of Carboxylic Acids using NaNH2(BH3)2, a Hydroboration Reagent with Reducing Capability between NaBH4and LiAlH4
-
Hydroboration reactions of carboxylic acids using sodium aminodiboranate (NaNH2[BH3]2, NaADBH) to form primary alcohols were systematically investigated, and the reduction mechanism was elucidated experimentally and computationally. The transfer of hydride ions from B atoms to C atoms, the key step in the mechanism, was theoretically illustrated and supported by experimental results. The intermediates of NH2B2H5, PhCH= CHCOOBH2NH2BH3-, PhCH= CHCH2OBO, and the byproducts of BH4-, NH2BH2, and NH2BH3- were identified and characterized by 11B and 1H NMR. The reducing capacity of NaADBH was found between that of NaBH4 and LiAlH4. We have thus found that NaADBH is a promising reducing agent for hydroboration because of its stability and easy handling. These reactions exhibit excellent yields and good selectivity, therefore providing alternative synthetic approaches for the conversion of carboxylic acids to primary alcohols with a wide range of functional group tolerance.
- Wang, Jin,Ju, Ming-Yue,Wang, Xinghua,Ma, Yan-Na,Wei, Donghui,Chen, Xuenian
-
p. 5305 - 5316
(2021/04/12)
-
- PNO ligand containing planar chiral ferrocene and application thereof
-
The invention discloses a PNO ligand containing planar chiral ferrocene and application thereof. The PNO ligand containing planar chiral ferrocene is a planar chiral ferrocene-containing and phenol-containing PNO ligand as shown in a general formula (I) or (II) which is described in the specification, or a planar chiral ferrocene-containing and aryl-phosphoric-acid-containingPNO ligand containing as shown in a general formula (III) or (IV) which is described in the specification, or a planar chiral ferrocene-containing and carbon-chiral-phenol-containingPNO ligand as shown in a general formula (V) or (VI) which is described in the specification. The invention provides tridentate PNO ligands and processes for their complexation with transition metal salts or transition metal complexes; the introduction of salicylaldehyde and derivatives thereof, which are simple and easy to obtain, enables the ligands to have a bifunctionalization effect, and -OH in a formed catalyst has stronger acidity and is beneficial to combination with N/O in polar double bonds. Therefore, due to the bifunctionalization effect of the catalyst, the interaction between the catalyst and a substrate can be greatly improved, so a reaction can obtain higher catalytic activity and stereoselectivity.
- -
-
Paragraph 0114-0118
(2021/06/21)
-
- Copper(i) pyrimidine-2-thiolate cluster-based polymers as bifunctional visible-light-photocatalysts for chemoselective transfer hydrogenation of α,β-unsaturated carbonyls
-
The photoinduced chemoselective transfer hydrogenation of unsaturated carbonyls to allylic alcohols has been accomplished using cluster-based MOFs as bifunctional visible photocatalysts. Assemblies of hexanuclear clusters [Cu6(dmpymt)6] (1, Hdmpymt = 4,6-dimethylpyrimidine-2-thione) as metalloligands with CuI or (Ph3P)CuI yielded cluster-based metal organic frameworks (MOFs) {[Cu6(dmpymt)6]2[Cu2(μ-I)2]4(CuI)2}n (2), {[Cu6(dmpymt)6]2[Cu2(μ-I)2]4}n (3), respectively. Nanoparticles (NPs) of 2 and 3 served both as photosensitizers and photocatalysts for the highly chemoselective reduction of unsaturated carbonyl compounds to unsaturated alcohols with high catalytic activity under blue LED irradiation. The photocatalytic system could be reused for several cycles without any obvious loss of efficiency.
- Zhang, Meng Juan,Young, David James,Ma, Ji Long,Shao, Guo Quan
-
p. 14899 - 14904
(2021/05/19)
-
- Carbon molecular sieve supported pd catalyzed hydrogenation of cinnamaldehyde in alkaline medium
-
Synthesis of various fine chemicals and pharmaceuticals are regulated through selective hydrogenation of α,β-unsaturated aldehydes. Hydrocinnamaldehyde is one of the important compounds in perfumery and flavouring industries. It is highly precarious and challenging to control the product selectivity as well as conversion in cinnamaldehyde hydrogenation. In this study, an effective hydrogenation of cinnamaldehyde was attained in presence of aqueous-protic organic medium by utilizing Pd/CMS and other additives of alkali such as K2CO3. The Pd/CMS catalyst along with alkali media catalyzed the hydrogenation of C=C selectively in cinnamaldehyde in order to form hydrocinnamaldehyde with 100% conversion rate. Additionally, the parallel hydrogenation of C=O and C=C bonds in cinnamaldehyde takes place in absence of media. The C=O bond reduction in cinnamaldehyde can be restricted through K2CO3 addition to aqueous-protic solution. The active sites of palladium were found to be uniform and analyzed using HRTEM data. Based on the mechanism involved in micropores of carbon molecular sieves, the key role of promoter is associated with hydrogenation of cinnamaldehyde. The catalytic criterion was appropriate with the acquired activity data.
- Krishna, Racharla,Ramakrishna, Chowdam,Saini, Bijendra,Gopi, Thakkallapalli,Swetha, Gujarathi,Shekar, Sridara Chandra,Srinivas, Ankanagari
-
p. 846 - 852
(2021/04/09)
-
- A Cationic Ru(II) Complex Intercalated into Zirconium Phosphate Layers Catalyzes Selective Hydrogenation via Heterolytic Hydrogen Activation
-
Catalytic hydrogenations constitute economic and clean transformations to produce pharmaceutical and a multitude of fine chemicals in chemical industry. Herein, we report a cationic Ru(II) complex intercalated into zirconium phosphate (ZrP) layers that enables the efficient catalytic conversion of furfural and other biomass-derived carbonyl compounds into the corresponding alcohols through selective hydrogenation of C=O group. The ZrP layers acted not only as a support for the Ru-complex, but also as the new ligands to tune the Ru(II) center via forming Ru?O bond. The resulting catalysts exhibit excellent catalytic performance and can be easily recycled for six times without significant loss of activity and selectivity. The Ru(II) complex-intercalated catalysts have been characterized by XRD, SEM, HRTEM, HAADF-STEM, XPS, FT-IR, DR-UV/Vis, EXAFS and XANES. Especially, it is observed that the appropriate interlayer spacing between ZrP layers is favorable to stabilize the Ru(II) complex. Notably, on the basis of the further characterization and density functional theory (DFT) calculation, it is identified that the interaction of cationic Ru(II) complex and P?OH group within ZrP layers leads to the high catalytic performance in selective hydrogenation, and the newly formed Ru?O?P species plays a crucial role in the heterolytic hydrogen activation and selective hydrogenation of biomass-derived compounds containing a carbonyl group.
- Chen, Manyu,Xia, Jie,Li, Huan,Zhao, Xiuge,Peng, Qingpo,Wang, Jiajia,Gong, Honghui,Dai, Sheng,An, Pengfei,Wang, Haifeng,Hou, Zhenshan
-
p. 3801 - 3814
(2021/08/03)
-
- Ir nanoclusters confined within hollow MIL-101(Fe) for selective hydrogenation of α,β-unsaturated aldehyde
-
Although the selective hydrogenation of α,β-unsaturated aldehyde to unsaturated alcohol (UOL) is an extremely important transformation, it is still a great challenge to achieve high selectivity to UOL due to thermodynamic favoring of the C[dbnd]C hydrogenation over the C[dbnd]O hydrogenation. Herein, we report that iridium nanoclusters (Ir NCs) confined within hollow MIL-101(Fe) expresses satisfied reaction activity (93.9%) and high selectivity (96.2%) for the hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) under 1 bar H2 atmosphere and room temperature. The unique hollow structure of MIL-101(Fe) benefits for the fast transport of reactant, ensuring the comparable reaction activity and better recyclability of Ir@MIL-101(Fe) than the counterparts which Ir NCs were on the surface of MIL-101(Fe). Furthermore, The X-ray photoelectron spectroscopy data indicates the electropositive Ir NCs, owing to the electron transfer from Ir to MIL-101(Fe), can interact with oxygen lone pairs, and Fourier transform infrared spectrum shows the Lewis acid sites in MIL-101(Fe) can strongly interact with C[dbnd]O bond, which contributes to a high selectivity for COL. This work suggests the considerable potential of synergetic effect between hollow MOFs and metal nanoclusters for selective hydrogenation reactions.
- Chen, Yurong,Li, Guangqin,Li, Yinle,Liu, Qian,Liu, Qinghua,Liu, Qinglin,Su, Hui
-
supporting information
(2021/08/13)
-
- Dual utility of a single diphosphine-ruthenium complex: A precursor for new complexes and, a pre-catalyst for transfer-hydrogenation and Oppenauer oxidation
-
The diphosphine-ruthenium complex, [Ru(dppbz)(CO)2Cl2] (dppbz = 1,2-bis(diphenylphosphino)benzene), where the two carbonyls are mutually cis and the two chlorides are trans, has been found to serve as an efficient precursor for the synthesis of new complexes. In [Ru(dppbz)(CO)2Cl2] one of the two carbonyls undergoes facile displacement by neutral monodentate ligands (L) to afford complexes of the type [Ru(dppbz)(CO)(L)Cl2] (L = acetonitrile, 4-picoline and dimethyl sulfoxide). Both the carbonyls in [Ru(dppbz)(CO)2Cl2] are displaced on reaction with another equivalent of dppbz to afford [Ru(dppbz)2Cl2]. The two carbonyls and the two chlorides in [Ru(dppbz)(CO)2Cl2] could be displaced together by chelating mono-anionic bidentate ligands, viz. anions derived from 8-hydroxyquinoline (Hq) and 2-picolinic acid (Hpic) via loss of a proton, to afford the mixed-tris complexes [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], respectively. The molecular structures of four selected complexes, viz. [Ru(dppbz)(CO)(dmso)Cl2], [Ru(dppbz)2Cl2], [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], have been determined by X-ray crystallography. In dichloromethane solution, all the complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the complexes shows redox responses within 0.71 to -1.24 V vs. SCE. [Ru(dppbz)(CO)2Cl2] has been found to serve as an excellent pre-catalyst for catalytic transfer-hydrogenation and Oppenauer oxidation.
- Mukherjee, Aparajita,Bhattacharya, Samaresh
-
p. 15617 - 15631
(2021/05/19)
-
- Ambient-pressure highly active hydrogenation of ketones and aldehydes catalyzed by a metal-ligand bifunctional iridium catalyst under base-free conditions in water
-
A green, efficient, and high active catalytic system for the hydrogenation of ketones and aldehydes to produce corresponding alcohols under atmospheric-pressure H2 gas and ambient temperature conditions was developed by a water-soluble metal–ligand bifunctional catalyst [Cp*Ir(2,2′-bpyO)(OH)][Na] in water without addition of a base. The catalyst exhibited high activity for the hydrogenation of ketones and aldehydes. Furthermore, it was worth noting that many readily reducible or labile functional groups in the same molecule, such as cyan, nitro, and ester groups, remained unchanged. Interestingly, the unsaturated aldehydes can be also selectively hydrogenated to give corresponding unsaturated alcohols with remaining C=C bond in good yields. In addition, this reaction could be extended to gram levels and has a large potential of wide application in future industrial.
- Wang, Rongzhou,Yue, Yuancheng,Qi, Jipeng,Liu, Shiyuan,Song, Ao,Zhuo, Shuping,Xing, Ling-Bao
-
-
- Method for synthesizing unsaturated primary alcohol in water phase
-
The invention discloses a method for synthesizing unsaturated primary alcohol in a water phase. The method comprises the following steps: taking unsaturated aldehyde as a raw material, selecting water as a solvent, and carrying out catalytic hydrogenation reaction on the unsaturated aldehyde in the presence of a water-soluble catalyst to obtain the unsaturated primary alcohol, wherein the catalyst is a metal iridium complex [Cp * Ir (2, 2'-bpyO)(OH)][Na]. Water is used as the solvent, so that the use of an organic solvent is avoided, and the method is more environment-friendly; the reaction is carried out at relatively low temperature and normal pressure, and the reaction conditions are mild; alkali is not needed in the reaction, so that generation of byproducts is avoided; and the conversion rate of the raw materials is high, and the yield of the obtained product is high. The method not only has academic research value, but also has a certain industrialization prospect.and.
- -
-
Paragraph 0024-0029
(2021/07/14)
-
- Synthesis, crystal and structural characterization, Hirshfeld surface analysis and DFT calculations of three symmetrical and asymmetrical phosphonium salts
-
Three stable phosphonium salts of 1,4-butanediylebis(triphenylphosphonium) dibromide I, butane-4?bromo-1-(triphenylphosphonium) bromide II and 1,3-propanediylbis(triphenylphosphonium) tetrahydroborate III were synthesized and structurally characterized. Single crystal X-ray diffraction analysis, spectroscopic methods and thermal analysis methods were used for the characterization of titled compounds. Crystallographic data showed that compound I crystallized in the triclinic crystal system with Pī space group and compound II crystallized in the monoclinic crystal system with P21/c space group. The crystal packing structures of I and II were stabilized by various intermolecular interactions, especially of C–H···π contacts. The molecular Hirshfeld surface analysis and 2D fingerprint revealed that the C···H contacts have 24.3% and 18.4% contributions in the crystal packings of compounds I and II, respectively. In addition, the H···Br (28.5%) contact has a considerable contribution to the crystal architecture of compound II. Theoretical studies were performed by DFT method to investigate the structural properties of the titled compounds. The isotopic ratio of boron in tetrahydroborate anion of compound III calculated by 1H NMR spectroscopy. The isotopic ratio for 10B/11B was 19.099 / 80.900%. Reduction of some carbonyl compounds to corresponding alcohols was performed by compound III and the optimum conditions were determined.
- Delaram, Behnaz,Gholizadeh, Mostafa,Makari, Faezeh,Nokhbeh, Seyed Reza,Salimi, Alireza
-
-
- Reduction of carbonyl compounds via hydrosilylation catalyzed by well-defined PNP-Mn(I) hydride complexes
-
Reduction reactions of unsaturated compounds are fundamental transformations in synthetic chemistry. In this context, the reduction of polarized double bonds such as carbonyl or C=C motifs can be achieved by hydrogenation reactions. We describe here a highly chemoselective Mn(I)-based PNP pincer catalyst for the hydrosilylation of aldehydes and ketones employing polymethylhydrosiloxane (PMHS) as inexpensive hydrogen donor. Graphic abstract: [Figure not available: see fulltext.]
- Weber, Stefan,Iebed, Dina,Glatz, Mathias,Kirchner, Karl
-
p. 635 - 639
(2021/06/17)
-
- Ruthenium(II) Complex of a Tridentate Azoaromatic Pincer Ligand and its Use in Catalytic Transfer Hydrogenation of Aldehydes and Ketones with Isopropanol
-
In this work, a new Ru(II) complex with the redox-active pincer 2,6-bis(phenylazo)pyridine ligand (L) is reported which acts as a metal-ligand bifunctional catalyst for transfer hydrogenation reactions. The isolated complex [(L)Ru(PMe2Ph)2(CH3CN)](ClO4)2; [1](ClO4)2 is characterized by a host of spectroscopic measurements and X-ray structure determination. It is diamagnetic and single-crystal X-ray structure analysis reveals that [1]2+ adopts a distorted octahedral geometry where L binds Ru center in meridional fashion. The observed elongation in the coordinated azo bond length (1.29 ?) is attributed to the extensive π-back bonding, dπ(RuII)→π*(azo)L. The complex [1](ClO4)2 acts as an efficient catalyst, which brings about catalytic transfer hydrogenation reactions of a broad array of aldehydes and ketones in isopropanol and in inert conditions. The selectivity of the catalyst for aldehyde reduction over the other reducible functional groups such as nitro, nitrile, ester etc was also investigated. Mechanistic studies, examined by suitable control reactions and isotope labelling experiments, indicate synergistic participation of both ligand and metal centres via the formation of a fleeting Ru?H intermediate and hydrogen walking to the coordinated azo function of L.
- Saha, Tanushri,Prasad Rath, Santi,Goswami, Sreebrata
-
p. 1455 - 1461
(2021/05/18)
-
- Hf-MOF catalyzed Meerwein?Ponndorf?Verley (MPV) reduction reaction: Insight into reaction mechanism
-
Hf-MOF-808 exhibits excellent activity and specific selectivity on the hydrogenation of carbonyl compounds via a hydrogen transfer strategy. Its superior activity than other Hf-MOFs is attributed to its poor crystallinity, defects and large specific surface area, thereby containing more Lewis acid-base sites which promote this reaction. Density functional theory (DFT) computations are performed to explore the catalytic mechanism. The results indicate that alcohol and ketone fill the defects of Hf-MOF to form a six-membered ring transition state (TS) complex, in which Hf as the center of Lewis stearic acid coordinates with the oxygen of the substrate molecule, thus effectively promoting hydrogen transfer process. Other reactive groups, such as –NO2, C = C, -CN, of inadequate hardness or large steric hindrance are difficult to coordinate with Hf, thus weakening their catalytic effect, which explains the specific selectivity Hf-MOF-808 for reducing the carbonyl group.
- Lin, Yamei,Bu, Qingxia,Xu, Jiaxian,Liu, Xiao,Zhang, Xueping,Lu, Guo-Ping,Zhou, Baojing
-
-
- KB3H8: An environment-friendly reagent for the selective reduction of aldehydes and ketones to alcohols
-
Selective reduction of aldehydes and ketones to their corresponding alcohols with KB3H8, an air- and moisture-stable, nontoxic, and easy-to-handle reagent, in water and THF has been explored under an air atmosphere for the first time. Control experiments illustrated the good selectivity of KB3H8 over NaBH4 for the reduction of 4-acetylbenzaldehyde and aromatic keto esters. This journal is
- Li, Xinying,Mi, Tongge,Guo, Wenjing,Ruan, Zhongrui,Guo, Yu,Ma, Yan-Na,Chen, Xuenian
-
supporting information
p. 12776 - 12779
(2021/12/10)
-
- Ternary Catalysis Enabled Three-Component Asymmetric Allylic Alkylation as a Concise Track to Chiral α,α-Disubstituted Ketones
-
Multicomponent reactions that involve interception of onium ylides through Aldol, Mannich, and Michael addition with corresponding bench-stable acceptors have demonstrated broad applications in synthetic chemistry. However, because of the high reactivity and transient survival of these in situ generated intermediates, the substitution-type interception process, especially the asymmetric catalytic version, remains hitherto unknown. Herein, a three-component asymmetric allylation of α-diazo carbonyl compounds with alcohols and allyl carbonates is disclosed by employing a ternary cooperative catalysis of achiral Pd-complex, Rh2(OAc)4, and chiral phosphoric acid CPA. This method represents the first example of three-component asymmetric allylic alkylation through an SN1-type trapping process, which involves a convergent assembly of two active intermediates, Pd-allyl species, and enol derived from onium ylides, providing an expeditious access to chiral α,α-disubstituted ketones in good to high yields with high to excellent enantioselectivity. Combined experimental and computational studies have shed light on the mechanism of this novel three-component reaction, including the critical role of Xantphos ligand and the origin of enantioselectivity.
- Chang, Wenju,Fu, Xiang,Hu, Wenhao,Kang, Zhenghui,Liang, Yong,Tian, Xue,Xu, Xinfang,Zhao, Wenxuan
-
p. 20818 - 20827
(2021/12/17)
-
- Me3SI-promoted chemoselective deacetylation: a general and mild protocol
-
A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
- Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
-
p. 19310 - 19315
(2021/06/03)
-
- Markovnikov Wacker-Tsuji Oxidation of Allyl(hetero)arenes and Application in a One-Pot Photo-Metal-Biocatalytic Approach to Enantioenriched Amines and Alcohols
-
The Wacker-Tsuji aerobic oxidation of various allyl(hetero)arenes under photocatalytic conditions to form the corresponding methyl ketones is presented. By using a palladium complex [PdCl2(MeCN)2] and the photosensitizer [Acr-Mes]ClO4 in aqueous medium and at room temperature, and by simple irradiation with blue led light, the desired carbonyl compounds were synthesized with high conversions (>80%) and excellent selectivities (>90%). The key process was the transient formation of Pd nanoparticles that can activate oxygen, thus recycling the Pd(II) species necessary in the Wacker oxidative reaction. While light irradiation was strictly mandatory, the addition of the photocatalyst improved the reaction selectivity, due to the formation of the starting allyl(hetero)arene from some of the obtained by-products, thus entering back in the Wacker-Tsuji catalytic cycle. Once optimized, the oxidation reaction was combined in a one-pot two-step sequential protocol with an enzymatic transformation. Depending on the biocatalyst employed, i. e. an amine transaminase or an alcohol dehydrogenase, the corresponding (R)- and (S)-1-arylpropan-2-amines or 1-arylpropan-2-ols, respectively, could be synthesized in most cases with high yields (>70%) and in enantiopure form. Finally, an application of this photo-metal-biocatalytic strategy has been demonstrated in order to get access in a straightforward manner to selegiline, an anti-Parkinson drug. (Figure presented.).
- Albarrán-Velo, Jesús,Gotor-Fernández, Vicente,Lavandera, Iván
-
p. 4096 - 4108
(2021/08/19)
-
- Sodium Aminodiboranate, a New Reagent for Chemoselective Reduction of Aldehydes and Ketones to Alcohols
-
Sodium aminodiboranate (NaNH 2(BH 3) 2, NaADBH) is a new member of the old borane family, which exhibits superior performance in chemoselective reduction. Experimental results show that NaADBH can rapidly reduce aldehydes and ketones to the corresponding alcohols in high efficiency and selectivity under mild conditions. There are little steric and electronic effects on this reduction.
- Wang, Jin,Guo, Yu,Li, Shouhu,Chen, Xuenian
-
supporting information
p. 1104 - 1108
(2021/05/25)
-
- Silver-Catalyzed Hydroboration of C-X (X = C, O, N) Multiple Bonds
-
AgSbF6 was developed as an effective catalyst for the hydroboration of various unsaturated functionalities (nitriles, alkenes, and aldehydes). This atom-economic chemoselective protocol works effectively under low catalyst loading, base- A nd solvent-free moderate conditions. Importantly, this process shows excellent functional group tolerance and compatibility with structurally and electronically diverse substrates (>50 examples). Mechanistic investigations revealed that the reaction proceeds via a radical pathway. Further, the obtained N,N-diborylamines were showcased to be useful precursors for amide synthesis.
- Pandey, Vipin K.,Tiwari, Chandra Shekhar,Rit, Arnab
-
supporting information
p. 1681 - 1686
(2021/03/03)
-
- Ruthenium (II) quinoline-azoimine complex: Synthesis, crystalline structures spectroelectrochemistry and catalytic properties
-
An octahedral ruthenium(II) complex with the general formula [RuII(Y)(bpy)Cl](ClO4) {Y= C6H5N=C(COCH3)-N=NC9H6N and bpy = 2,2′-bipyrdine} (1) was synthesized. The new ligand (Y) is coordinated to ruthenium via quinoline-N, imine-N and azo-N atoms. Both the novel complex 1 and the new ligand H2Y were structurally characterized by X-ray crystallography, spectroscopic (IR, UV–Vis and NMR spectroscopy) and electrochemical (cyclic voltammetry) techniques. The bonding in 1 and its published skeletal isomer [RuII(L1)(bpy)Cl](PF6) {L1 = C6H5N=N-C(COCH3) = NC9H6N5} (1A) has been analyzed using molecular orbital theory. The novel tridentate ligand (Y) stabilizes the Ru(II) oxidation state showing the Ru(III/II) couple at 1.05 V vs. Cp2Fe/Cp2Fe+. The potential use of 1 as a catalyst for hydrogenation of α, β-unsaturated aldehyde has been investigated. UV/Vis and IR-spectroelectrochemistry on complex 1 were performed.
- Abdel-Rahman, Obadah S.,Al-Noaimi, Mousa,Alwahsh, Manal I.,Awwadi, Firas F.,Hammoudeh, Ayman
-
-
- Rational Localization of Metal Nanoparticles in Yolk–Shell MOFs for Enhancing Catalytic Performance in Selective Hydrogenation of Cinnamaldehyde
-
The development of sustainable catalysts to simultaneously improve activity and selectivity remains a challenge. Herein, it is demonstrated that metal nanoparticles (MNPs) can be encapsulated into a yolk–shell metal–organic framework (MOF) with controllable spatial localization to optimize catalytic performance. When the MNPs are located in the void space between the shell and the core of the MOF, the resulting MNPs@MOF composites show both high catalytic activity and selectivity toward the hydrogenation of α,β-unsaturated aldehydes. In particular, the easily recoverable and stable Ptvoid@MOF(Y) shows an exceptionally high selectivity of 98.2 % for cinnamyl alcohol at a high conversion of 97 %. The excellent performance can be attributed to easy diffusion of the reactants to access highly exposed MNPs in the MOF support, as well as the improved adsorption of the reactant and desorption of the product due to the appropriate metal–support interaction and rich void space between core and shell.
- Zhou, Awu,Dou, Yibo,Zhou, Jian,Li, Jian-Rong
-
p. 205 - 211
(2019/11/03)
-
- Fe-Co Alloyed Nanoparticles Catalyzing Efficient Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol in Water
-
Selective hydrogenation of C=O against the conjugated C=C in cinnamaldehyde (CAL) is indispensable to produce cinnamyl alcohol (COL). Nonetheless, it is challenged by the low selectivity and the need to use organic solvents. Herein, for the first time, we report the use of Fe-Co alloy nanoparticles (NPs) on N-doped carbon support as a selective hydrogenation catalyst to efficiently convert CAL to COL. The resultant catalyst with the optimized Fe/Co ratio of 0.5 can achieve an exceptional COL selectivity of 91.7 % at a CAL conversion of 95.1 % in pure water medium under mild reaction conditions, ranking it the best performed catalyst reported to date. The experimental results confirm that the COL selectivity and CAL conversion efficiency are, respectively promoted by the presence of Fe and Co, while the synergism of the alloyed Fe-Co is the key to concurrently achieve high COL selectivity and CAL conversion efficiency.
- Chen, Chun,Gong, Wanbing,Han, Miaomiao,Lv, Yang,Wang, Dongdong,Wang, Guozhong,Zhang, Haimin,Zhao, Huijun
-
supporting information
p. 23521 - 23526
(2020/10/26)
-
- Synergistic Relay Reactions To Achieve Redox-Neutral α-Alkylations of Olefinic Alcohols with Ruthenium(II) Catalysis
-
Herein, we report a ruthenium-catalyzed redox-neutral α-alkylation of unsaturated alcohols based on a synergistic relay process involving olefin isomerization (chain walking) and umpolung hydrazone addition, which takes advantage of the interaction between the two rather inefficient individual reaction steps to enable an efficient overall process. This transformation shows the compatibility of hydrazone-type “carbanions” and active protons in a one-pot reaction, and at the same time achieves the first Grignard-type nucleophilic addition using olefinic alcohols as latent carbonyl groups, providing a higher yield of the corresponding secondary alcohol than the classical hydrazone addition to aldehydes does. A broad scope of unsaturated alcohols and hydrazones, including some complex structures, can be successfully employed in this reaction, which shows the versatility of this approach and its suitability as an alternative, efficient means for the generation of secondary and tertiary alcohols.
- Kan, Jian,Li, Chao-Jun,Li, Chen-Chen,Li, Jianbin,Lv, Leiyang,Qiu, Zihang
-
supporting information
p. 4544 - 4549
(2020/02/04)
-
- Highly Regio- A nd Enantioselective Hydrogenation of Conjugated α-Substituted Dienoic Acids
-
Highly regio- A nd enantioselective hydrogenation of conjugated α-substituted dienoic acids was realized for the first time using Trifer-Rh complex, providing a straightforward method for the synthesis of chiral α-substituted ?,?′-unsaturated acids. DFT calculations revealed N+H-O hydrogen bonding interaction is formed to stabilize the transition state and the coordination of 4,5-double bond to Rh(III) center would facilitate the reductive elimination process. This hydrogenation provided a gram-scale synthesis of the precursor of sacubitril.
- Liu, Xian,Liu, Song,Wang, Quanjun,Zhou, Gang,Yao, Lin,Ouyang, Qin,Jiang, Ru,Lan, Yu,Chen, Weiping
-
supporting information
p. 3149 - 3154
(2020/04/09)
-
- Amorphous Nickel Phosphide Nanoparticles for Selective Hydrogenation of Cinnamaldehyde
-
Abstract: The selective hydrogenation of α,β-unsaturated aldehydes plays a crucial role in industrial production, and an efficient non-noble metal catalyst for it has been pursued to reduce the cost. Herein, we report an amorphous nickel phosphide for the selective hydrogenation of cinnamaldehyde. Compared to crystalline nickel phosphide, amorphous nickel phosphide showed both high activity and high selectivity to target products. Its catalytic performance was also better than that of commercial Pd/C catalyst. In addition, initial P/Ni ratio was found to be an important factor to affect the activity of amorphous nickel phosphide. High initial P/Ni ratio led to high activity owing to small particles, high surface area and strong metallicity of as-synthesized catalyst. Moreover, excellent catalytic performances of amorphous nickel phosphide were observed in the selective hydrogenation of different α,β-unsaturated aldehydes and ketones. Graphic Abstract: [Figure not available: see fulltext.].
- Liu, Ping,Zhu, Ya-Lu,Zhou, Lei,Zhang, Wei-Hong,Li, Yong-Xin
-
p. 2695 - 2702
(2020/03/23)
-
- Pd nanoparticles confined in mesoporous N-doped carbon silica supports: A synergistic effect between catalyst and support
-
Palladium nanoparticles of similar size were deposited on different supports, layers of carbon materials (with and without nitrogen doping) on the surface of a MCF (mesocellular foam) silica. For the generation of the N-doped carbon coatings, three different N sources were used to also investigate a possible influence of the N-doped carbon precursor and thus the structure of the N-doped carbons on their performance as catalyst support. These catalysts were tested for the Suzuki coupling and hydrogenation reactions. For the Suzuki reaction, the carbon coatings showed to increase dramatically the stability of the MCF material. Furthermore, when N-doped carbon coatings were applied, strong improvement of the stability of the catalysts was observed due to an enhanced interaction between metal nanoparticles and the support, preventing metal particle growth. In hydrogenation reactions, the presence of the N-doped carbon coating on the silica support increases the adsorption of aromatic compounds causing an enhancement of the catalytic activity of Pd NPs when compared to the non-doped supports.
- Kerstien, Julius,Oliveira, Rafael L.,Schom?cker, Reinhard,Thomas, Arne
-
p. 1385 - 1394
(2020/03/26)
-
- Chemoselective hydrogenation of α,β-unsaturated aldehydes over Rh nanoclusters confined in a metal-organic framework
-
Selective hydrogenation of α,β-unsaturated aldehydes to achieve high selectivity towards a desirable product is still a great challenge mainly because of the complex conjugate system. Herein, Rh nanoclusters encapsulated in MIL-101 (Cr), synthesized by the double solvent method, are able to selectively hydrogenate C-C of cinnamaldehyde, an α,β-unsaturated aldehyde and achieve over 98percent selectivity with a conversion of 98percent to a saturated aldehyde under mild conditions. Fourier transform infrared spectroscopy confirms that MIL-101 acts as an aldehyde protector to suppress the reactivity of C-O, and the X-ray photoelectron spectroscopy (XPS) data indicate that the electropositive Rh, owing to the electron transfer from Rh to MIL-101, preferentially absorbs C-C rather than C-O leading to -improvement of the selectivity towards saturated aldehydes. In addition, Rh@MIL-101 can also efficiently catalyse hydrodefluorination of aryl fluorides with good stability. This work provides a basic strategy to develop other selective heterogeneous catalystsviastructural modulation for synergetic catalysis.
- Liu, Qinglin,Li, Yinle,Fan, Yanan,Su, Cheng-Yong,Li, Guangqin
-
supporting information
p. 11442 - 11447
(2020/06/29)
-
- Producing of cinnamyl alcohol from cinnamaldehyde over supported gold nanocatalyst
-
Chemoselective hydrogenation of unsaturated aldehyde to unsaturated alcohol has attracted growing interests in recent years due to its widespread applications in fine chemicals. However, the hydrogenation of the C=O bond was thermodynamically and kinetically unfavorable over the hydrogenation of the C=C bond. Thus, to obtain the unsaturated alcohol from the unsaturated aldehyde is very difficult in most of the catalytic systems. In this work, ZnAl-hydrotalcite-supported cysteine-capped Au25 nanoclusters were used as the precatalysts for chemoselective hydrogenation of cinnamaldehyde to cinnamyl alcohol. The catalyst showed stable high selectivity (~ 95percent) at prolonged reaction time and complete conversion of the substrate. According to the results of the control experiments, the in-situ DRIFTS of the substrate under high pressure of hydrogen and the 27Al MAS-NMR spectroscopy, we proposed that the difference of the preferential adsorption of the C=O bond to that of the C=C bond was derived from the nature of the support of the gold catalysts.
- Liu, Fei,Liu, Xiaoyan,Tan, Yuan,Wang, Aiqin,Zhang, Leilei,Zhang, Tao
-
p. 470 - 481
(2020/07/31)
-
- Production of γ-Valerolactone from One-Pot Transformation of Biomass-Derived Carbohydrates Over Chitosan-Supported Ruthenium Catalyst Combined with Zeolite ZSM-5
-
It remains as a challenge to directly transform the biomass-derived C5 carbohydrates, such as furfural (FF) and its upstream product xylose and hemicellulose, to γ-valerolactone (GVL), a versatile renewable chemical platform, due to various restrictions in the current synthetic strategies. Using formic acid as green hydrogen source, we synthesized the recyclable chitosan-Ru/PPh3 catalyst system, effective for both the hydrogenation of FF to furfuryl alcohol (FAL) and the reduction of levulinic acid (LA) or ethyl levulinate (EL) to GVL, affording up to 99 % product yields. The combination of chitosan-Ru/PPh3 with ZSM-5 could successfully achieve up to 79 % yield of GVL from one-pot conversion of FF under mild condition. Preliminary studies indicated that this method could also be applied to the direct conversion of biomass-derived C5 carbohydrates such as xylose and hemicellulose to GVL in 37 % or 30 % yield, respectively.
- Wang, Tianlong,He, Jianghua,Zhang, Yuetao
-
p. 1611 - 1619
(2020/03/04)
-
- Diethylsilane as a Powerful Reagent in Au Nanoparticle-Catalyzed Reductive Transformations
-
Diethylsilane (Et2SiH2), a simple and readily available dihydrosilane, that exhibits superior reactivity, as compared to monohydrosilanes, in a series of reductive transformations catalyzed by recyclable and reusable Au nanoparticles (1 mol-%) supported on TiO2. It reduces aldehydes or ketones almost instantaneously at ambient conditions. It can be used in a one pot rapid reductive amination procedure, in which premixing of aldehyde and amine is required prior to the addition of the reducing agent and the catalyst, even in a protic solvent. An unprecedented method for the synthesis of N-arylisoindolines is also shown in the reductive amination between o-phthalaldehyde and anilines. In this transformation, it is proposed that the intermediate N,2-diphenylisoindolin-1-imines are reduced stepwise to the isoindolines. Finally, Et2SiH2 readily reduces amides into amines in excellent yields and shorter reaction times relative to previously known analogous nano Au(0)-catalyzed protocols.
- Louka, Anastasia,Kidonakis, Marios,Saridakis, Iakovos,Zantioti-Chatzouda, Elisavet-Maria,Stratakis, Manolis
-
p. 3508 - 3514
(2020/06/02)
-
- Microwave-heated γ-Alumina Applied to the Reduction of Aldehydes to Alcohols
-
The development of cheap and robust heterogeneous catalysts for the Meerwein-Ponndorf-Verley (MPV) reduction is desirable due to the difficulties in product isolation and catalyst recovery associated with the traditional use of homogeneous catalysts for MPV. Herein, we show that microwave heated γ-Al2O3 can be used for the reduction of aldehydes to alcohols. The reaction is efficient and has a broad substrates scope (19 entries). The products can be isolated by simple filtration, and the catalyst can be regenerated. With the use of microwave heating, we can direct the heating to the catalyst rather than to the whole reaction medium. Furthermore, DFT was used to study the reaction mechanism, and we can conclude that a dual-site mechanism is operative where the aldehyde and 2-propoxide are situated on two adjacent Al sites during the reduction. Additionally, volcano plots were used to rationalize the reactivity of Al2O3 in comparison to other metal oxides.
- Dhokale, Bhausaheb,Susarrey-Arce, Arturo,Pekkari, Anna,Runemark, August,Moth-Poulsen, Kasper,Langhammer, Christoph,H?relind, Hanna,Busch, Michael,Vandichel, Matthias,Sundén, Henrik
-
p. 6344 - 6355
(2020/10/28)
-
- Efficient catalytic transfer hydrogenation reactions of carbonyl compounds by Ni(II)-diphosphine complexes
-
The catalytic transfer hydrogenation reactions of a series of aromatic and aliphatic carbonyl compounds were investigated using divalent Ni(II)-diphosphine complexes, [L2NiCl2] (where L2 = 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,1-bis(diphenylphosphino)ferrocene (dppf), and N-butyl-N-(diphenylphosphino)-1,1-diphenylphosphinamine (dppba)). This is a single-step reaction in the presence of potassium hydroxide and isopropyl alcohol to afford the corresponding alcohols. This protocol tolerates other sensitive functional groups like olefinic double bonds and also achieves high chemoselectivity. All the reactions were monitored by GC and GC–MS. The plausible mechanism is also discussed. The method reported in the present article is simple, cost-effective, and provides excellent conversions. Nickel-diphosphine complexes appear as a potential alternative to expensive transition metal complexes.
- Venkatesh, Sadhana,Panicker, Rakesh R.,Lenin Kumar, Verdhi,Pavankumar,Viswanath, Nukala,Singh, Shangrila,Desikan, Rajagopal,Sivaramakrishna, Akella
-
p. 2963 - 2977
(2020/11/03)
-
- Efficient One-Pot Reductive Aminations of Carbonyl Compounds with Aquivion-Fe as a Recyclable Catalyst and Sodium Borohydride
-
A one-pot reductive amination of aldehydes and ketones with NaBH4 was developed with a view to providing efficient, economical and greener synthetic conditions. A recyclable iron-based Lewis catalyst, Aquivion-Fe, was used to promote imine formation in cyclopentyl methyl ether, followed by the addition of a small amount of methanol to the reaction mixture to enable C=N reduction by NaBH4. The protocol, applied to a wide number of amines and carbonyl compounds, resulted in ever complete conversion of these latter with excellent chemoselectivity towards the expected amination products in the most cases. Isolated yields, determined for a selection of the screened substrates, were found consistent with the previously obtained conversion and selectivity data. Cinacalcet, an important active pharmaceutical ingredient, was efficiently prepared by the title procedure.
- Airoldi, Veronica,Piccolo, Oreste,Roda, Gabriella,Appiani, Rebecca,Bavo, Francesco,Tassini, Riccardo,Paganelli, Stefano,Arnoldi, Sebastiano,Pallavicini, Marco,Bolchi, Cristiano
-
supporting information
p. 162 - 168
(2019/12/11)
-
- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
-
A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
-
supporting information
p. 16702 - 16707
(2020/10/27)
-
- Enantioselective α-functionalization of 1,3-dithianes by iridium-catalyzed allylic substitution
-
An iridium-catalyzed asymmetric allylic substitution reaction with 2-alkoxy carbonyl-1,3-dithianes has been achieved with high regio- and enantioselectivities. The transformation provides a new method for the enantioselective α-functionalization of dithianes. The corresponding dithiane-containing products are easily converted into many other derivatives with high yields and enantioselectivities.
- Xie, Xingang,Tang, Shouchu,Wang, Xiaolei,Wang, Panpan,Jiang, Qian,Zhao, Ruibo
-
p. 12456 - 12467
(2020/11/09)
-
- Accelerating Chemo- And Regioselective Hydrogenation of Alkynes over Bimetallic Nanoparticles in a Metal-Organic Framework
-
Selective semihydrogenation of alkynes has been a long-term and significant target, yet it remains a great challenge. Herein, bimetallic nanoparticles in a metal-organic framework (MOF), i.e., CuPd&at;ZIF-8 composite, featuring a cubic CuPd core and a porous ZIF-8 shell, have been rationally fabricated for this end. Given the unique physicochemical properties, the Cu nanocubes can not only convert solar energy into heat to accelerate the reaction but also serve as the seed for in situ formation of Pd nanoparticles (NPs) on their external surface to regulate the chemoselectivity of Pd active sites. The additional growth of the MOF shell is helpful to stabilize the CuPd core and offer regioselectivity via the steric hindrance effect. Ammonia borane provides active hydrogen species to significantly boost the hydrogenation and ensure the high selectivity. As a result, the CuPd&at;MOF exhibits high efficiency, featuring a turnover frequency (TOF, 6799 min-1) of 5-105 times higher than that in previous reports, and high chemo- and regioselectivity toward the semihydrogenation of alkynes, in the presence of NH3BH3 as a hydrogen source, under visible-light irradiation at ambient temperature.
- Guan, Qiaoqiao,Jiang, Hai-Long,Li, Luyan,Lu, Junling,Yang, Qihao,Yang, Weijie,Yu, Shu-Hong
-
p. 7753 - 7762
(2020/08/21)
-
- Biocatalytic reduction of α,β-unsaturated carboxylic acids to allylic alcohols
-
We have developed robust in vivo and in vitro biocatalytic systems that enable reduction of α,β-unsaturated carboxylic acids to allylic alcohols and their saturated analogues. These compounds are prevalent scaffolds in many industrial chemicals and pharmaceuticals. A substrate profiling study of a carboxylic acid reductase (CAR) investigating unexplored substrate space, such as benzo-fused (hetero)aromatic carboxylic acids and α,β-unsaturated carboxylic acids, revealed broad substrate tolerance and provided information on the reactivity patterns of these substrates. E. coli cells expressing a heterologous CAR were employed as a multi-step hydrogenation catalyst to convert a variety of α,β-unsaturated carboxylic acids to the corresponding saturated primary alcohols, affording up to >99percent conversion. This was supported by the broad substrate scope of E. coli endogenous alcohol dehydrogenase (ADH), as well as the unexpected CC bond reducing activity of E. coli cells. In addition, a broad range of benzofused (hetero)aromatic carboxylic acids were converted to the corresponding primary alcohols by the recombinant E. coli cells. An alternative one-pot in vitro two-enzyme system, consisting of CAR and glucose dehydrogenase (GDH), demonstrates promiscuous carbonyl reductase activity of GDH towards a wide range of unsaturated aldehydes. Hence, coupling CAR with a GDH-driven NADP(H) recycling system provides access to a variety of (hetero)aromatic primary alcohols and allylic alcohols from the parent carboxylates, in up to >99percent conversion. To demonstrate the applicability of these systems in preparative synthesis, we performed 100 mg scale biotransformations for the preparation of indole-3-aldehyde and 3-(naphthalen-1-yl)propan-1-ol using the whole-cell system, and cinnamyl alcohol using the in vitro system, affording up to 85percent isolated yield.
- Aleku, Godwin A.,Leys, David,Roberts, George W.
-
p. 3927 - 3939
(2020/07/09)
-
- Hemin Catalyzed Dealkylative Intercepted [2, 3]-Sigmatropic Rearrangement Reactions of Sulfonium Ylides with 2, 2, 2-Trifluorodiazoethane
-
A dealkylative intercepted [2, 3]-sigmatropic rearrangement reaction of allylic sulfides with 2, 2, 2-trifluorodiazoethane (CF3CHN2) is reported, the commercially available and biocompatible catalyst hemin was found to efficiently catalyze this transformation across a diverse set of allylic sulfides with in situ generated CF3CHN2, providing excellent yields (up to 99%) under mild condition without inert gas protection. In addition, CF3CHN2 exhibited unique reactivity toward this process compared with other frequently used diazo reagents. This work expands the range of carbene-mediated transformations catalyzed by hemin and introduces a concise and general strategy for exploiting new possibility of reactions concerning organosulfides. (Figure presented.).
- Yan, Xiaojing,Li, Chang,Xu, Xiaofei,Zhao, Xiaoyong,Pan, Yuanjiang
-
p. 2005 - 2011
(2020/05/18)
-
