- Phenylpropanoid glycosides from Conyza japonica
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Three new phenylpropanoid glycosides, named 1-O-[3-O-acetyl-α-L- rhamnopyranosyl-(1→6)-β-D-glucopyranosyl]-3-hydroxycinnamaldehyde (1), 1-O-[2,3-O-diacetyl-α-L-rhamnopyranosyl-(1→6)-β-D- glucopyranosyl]-3-methoxycinnamaldehyde (2), and 1-O-[3-O-acetyl-α-L
- Hu, Jiang,Shi, Xiaodong,Ding, Wei,Chen, Jiangang,Li, Changsheng
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- CuBr2-LiOBut as a New Reagent for Oxidation of Alcohols
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The reagent of the title was found to promote the oxidation of alcohols to give the corresponding carbonyl compounds in good yields.The copper(II) oxidizing agent was easily prepared by the reaction of copper(II) bromide with lithium t-butoxide in THF.
- Yamaguchi, Jun-ichi,Yamamoto, Shiori,Takeda, Takeshi
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- Efficient preparation of trans-α,β-unsaturated aldehydes from saturated aldehydes by oxidative enamine catalysis
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A mild and highly efficient amine-catalyzed, IBX-mediated oxidation of aldehydes to (E) selective α,β-unsaturated aldehydes has been achieved in good yields. The process features a new oxidation of enamines to iminium ions in a catalytic fashion.
- Zhang, Shilei,Xie, Hexin,Song, Aiguo,Wu, Deyan,Zhu, Jin,Zhao, Sihan,Li, Jian,Yu, Xinhong,Wang, Wei
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- Switching the Z / e selectivity in the palladium(II)-catalyzed decarboxylative heck arylations of trans -cinnamaldehydes by solvent
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The Z/E selectivity of Pd(II)-catalyzed decarboxylative Heck-type arylations of trans-cinnamaldehydes can be controlled readily by switching the reaction solvent. Depending on the type of solvent used, each of the two isomeric products can be obtained with good to excellent Z/E ratio. In THF, Z-isomers were formed preferentially, whereas DMF provided the E-isomers predominantly.
- Ban, Shu-Rong,Wang, Hai-Ning,Toader, Violeta,Bohle, D. Scott,Li, Chao-Jun
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- The synthesis of 6,6,6-2H3-2E-hexenal
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6,6,6-2H3-2E-Hexenal, leaf-aldehyde, has been synthesised in 45% yield and 99.3% purity by reaction of 3,3,3-2H3-n-propyl magnesium bromide with an ethereal solution of 3-trimethylsiloxy-2-propenal (3) prepared in situ. This new one pot procedure alleviates the need to isolate (3) and should prove useful in the synthesis of other E-α,β-unsaturated aldehydes.
- Fielder,Rowan
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- Unravelling Some of the Key Transformations in the Hydrothermal Liquefaction of Lignin
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Using both experimental and computational methods, focusing on intermediates and model compounds, some of the main features of the reaction mechanisms that operate during the hydrothermal processing of lignin were elucidated. Key reaction pathways and their connection to different structural features of lignin were proposed. Under neutral conditions, subcritical water was demonstrated to act as a bifunctional acid/base catalyst for the dissection of lignin structures. In a complex web of mutually dependent interactions, guaiacyl units within lignin were shown to significantly affect overall lignin reactivity.
- Lui, Matthew Y.,Chan, Bun,Yuen, Alexander K. L.,Masters, Anthony F.,Montoya, Alejandro,Maschmeyer, Thomas
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- The preparation of acyl phosphonates by the heterogeneous oxidation of 1-hydroxy phosphonates
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The oxidation of hydroxy phosphonates to acyl phosphonates using three heterogeneous systems, MnO2, KMnO4 and CrO2, was investigated. The best results were obtained with CrO2 in refluxing acetofinitrile.
- Liao, Yihua,Shabany, Hossein,Spilling, Christopher D.
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- Selective oxidation of alcohols with a new reagent: Iron(III) nitrate supported on aluminum silicate
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A selective and effective oxidation of alcohols, except aliphatic alcohols, such as 1-hexanol or 1-octyl alcohol, to the corresponding aldehydes and ketones using a new reagent, iron(III) nitrate supported on aluminum silicate, under heterogeneous conditions with reflux with 85-98% yield is described. Copyright Taylor & Francis Group, LLC.
- Lou, Ji-Dong,Huang, Li-Hong,Marrogi, Aizen J.,Li, Feng,Li, Li,Gao, Chun-Ling
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- A highly efficient and recyclable silica-supported palladium catalyst for alcohol oxidation reaction
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A silica supported palladium catalyst (SiO2@APTES-Pd) showed excellent activity and reusability for selective oxidation of alcohols to corresponding carbonyl compounds with H2O2 as oxidant under base free environment. A wide range of alcohols including aliphatic alcohols are tolerated as substrates with a low loading of palladium (0.1 mol %).
- Sahu, Debojeet,Sarmah, Chandan,Das, Pankaj
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- The application of N,N′-dibromo-N,N′ -1,2-ethanediylbis-(p-toluenesulphonamide) as a powerful reagent for the oxidation of primary and secondary alcohols to aldehydes and ketones
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Aliphatic and benzylic alcohols are readily oxidized to aldehydes and ketones in good yields under mild conditions by N,N′-dibromo-N,N′ -1,2-ethanediylbis(p-toluenesulphonamide) [BNBTS].
- Ghorbani-Vaghei, Ramin,Khazaei, Ardeshir
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- New synthetic method of benzaldehydes and α,β-unsaturated aldehydes with I2 under photoirradiation
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Benzylic alcohols and allylic alcohols were found to be oxidized to the corresponding benzaldehydes and α,β-unsaturated aldehydes easily in the presence of I2 under photoirradiation.
- Itoh, Akichika,Kodama, Tomohiro,Masaki, Yukio
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- Sequential cross-metathesis/phosphorus-based olefination: stereoselective synthesis of 2,4-dienoates
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A variety of stereodefined 2,4-dienoates have been prepared in a stereoselective manner by sequencing olefin cross-metathesis (CM) with phosphorus-based olefination reactions (Wittig and Horner-Wadsworth-Emmons) in good yield using commercially available reagents.
- Paul, Tapas,Andrade, Rodrigo B.
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- SELECTIVE REDUCTION OF ALDEHYDES TO THE CORRESPONDING PRIMARY ALCOHOLS BY LITHIUM ENOLATE OF ACETALDEHYDE
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Reaction of lithium enolate of acetaldehyde (obtained by cycloreversion of THF in the presence of n-BuLi) with a number of nonenolizable aldehydes (aromatic, heteroaromatic, cinnamaldehyde) in THF and room temperature affords good to quantitative yields of the corresponding primary alcohols, instead of other products commonly reported for similar conditions.Reduction of the carbonyl group is the main reaction even in the presence of other reducible groups or parts of the same group.A possible mechanism of reaction is also proposed.
- Nunno, L. Di.,Scilimati, A.
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- Microwave-assisted oxidation of alcohols with N,N,N′,N′- tetrabromobenzene-1,3-disulfonamide and poly(N-bromobenzene-1,3-disulfonamide) under solvent-free conditions
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An efficient and mild methodology for the oxidation of primary and secondary alcohols to the corresponding carbonyl functions is described with N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide and poly(N-bromobenzene-1,3-disulfonamide) using microwave irradiation under solvent-free conditions. Aliphatic, benzylic and allylic alcohols are rapidly oxidized without over-oxidation to carboxylic acids. Secondary carbinols are slowly oxidized so that the reaction is highly chemoselective.
- Ghorbani-Vaghei, Ramin,Veisi, Hojat,Amiri, Mostafa
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- Highly regioselective terminal alkynes hydroformylation and Pauson-Khand reaction catalysed by mesoporous organised zirconium oxide based powders
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Zirconia-silica mesoporous powders act as very efficient heterogeneous catalysts for both alkyne hydroformylation and Pauson-Khand reaction and yield regioselectivities opposite to those usually observed. The Royal Society of Chemistry 2006.
- Goettmann, Frederic,Le Floch, Pascal,Sanchez, Clement
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- Oxidation of alcohols with hydrogen peroxide catalyzed by molybdenum(VI)-peroxo complex under solvent-free conditions
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The oxidation of primary, secondary, allylic, and aromatic alcohols to the corresponding carbonyl compounds proceeds in high yield catalyzed by molybdenum(VI)-peroxo complex with H2O2 under solvent-free conditions. Secondary -OH grou
- Luan, Yi,Wang, Ge,Luck, Rudy L.,Yang, Mu,Han, Xiao
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- Allylic amine formation by imination of allylic tellurides
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The imination of allylic phenyl tellurides with [N-(p-toluenesulfonyl)imino]phenyliodinane or chloramine-T affords the corresponding allylic amines via [2,3]sigmatropic rearrangement of the tellurimide intermediates in high yields. Application to chiral cinnamyl 2-(1-dimethylaminoethyl)ferrocenyl telluride results in the formation of the corresponding chiral allylic amine, 3-phenyl-3-tosylaminopropene, with 93% ee.
- Nishibayashi, Yoshiaki
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- Oxidative deselenylation with sodium perborate and sodium percarbonate
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In the presence of acetic anhydride, both sodium perborate and sodium percarbonate have been found to be effective reagents for the oxidation of α-phenylselenocarbonyl compounds to α,β-unsaturated carbonyl compounds.
- Kabalka,Reddy,Narayana
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- Selective solvent-free oxidation of alcohols with potassium dichromate
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Selective oxidation of primary alcohols to the corresponding aldehydes by potassium dichromate at room temperature under solvent-free conditions are described. This new procedure can also oxidise secondary alcohols.
- Lou, Ji-Dong,Xu, Zhi-Nan
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- Pt-Catalyzed selective oxidation of alcohols to aldehydes with hydrogen peroxide using continuous flow reactors
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The oxidation of alcohols to aldehydes is a powerful reaction pathway for obtaining valuable fine chemicals used in pharmaceuticals and biologically active compounds. Although many oxidants can oxidize alcohols, only a few hydrogen peroxide oxidations can be employed to continuously synthesize aldehydes in high yields using a liquid-liquid two-phase flow reactor, despite the possibility of the application toward a safe and rapid multi-step synthesis. We herein report the continuous flow synthesis of (E)-cinnamaldehyde from (E)-cinnamyl alcohol in 95%-98% yields with 99% selectivity for over 5 days by the selective oxidation of hydrogen peroxide using a catalyst column in which Pt is dispersed in SiO2. The active species for the developed selective oxidation is found to be zero-valent Pt(0) from the X-ray photoelectron spectroscopy measurements of the Pt surface before and after the oxidation. Using Pt black diluted with SiO2as a catalyst to retain the Pt(0) species with the optimal substrate and H2O2introduction rate not only enhances the catalytic activity but also maintains the activity during the flow reaction. Optimizing the contact time of the substrate with Pt and H2O2using a flow reactor is important to proceed with the selective oxidation to prevent the catalytic H2O2decomposition.
- Kon, Yoshihiro,Nakashima, Takuya,Yada, Akira,Fujitani, Tadahiro,Onozawa, Shun-Ya,Kobayashi, Shū,Sato, Kazuhiko
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supporting information
p. 1115 - 1121
(2021/02/16)
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- Oxoammonium-Mediated Allylsilane–Ether Coupling Reaction
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A new C(sp3)?H functionalization reaction consisting of the oxidative α-allylation of allyl- and benzyl- methyl ethers has been developed. The C?C coupling could be carried out under mild conditions thanks to the use of cheap and green oxoammonium salts. The scope of the reaction was studied over 27 examples, considering the nature of the substituents on the two coupling partners.
- Carlet, Federica,Bertarini, Greta,Broggini, Gianluigi,Pradal, Alexandre,Poli, Giovanni
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p. 2162 - 2168
(2021/04/02)
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- Pd(II)-Catalyzed CC Bond Cleavage by a Formal Group-Exchange Reaction
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A chelation-assisted palladium-catalyzed CC bond cleavage of α, β-unsaturated ketone to form alkenyl nitrile in the presence of nitrile is disclosed on the basis of a formal group-exchange reaction formulated as C1C2 + C3 → C1C3 + C2, differing from normal alkene oxidative cleavage and metathesis type. The isolated key active Pd(II) complex as well as deuterium-labeled experiment revealed the necessity of the chelation group, and a plausible catalytic pathway was proposed.
- Ye, Runyou,Zhu, Maoshuai,Yan, Xufei,Long, Yang,Xia, Ying,Zhou, Xiangge
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p. 8678 - 8683
(2021/07/26)
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- One-Pot Preparation of (E)-α,β-Unsaturated Aldehydes by a Julia-Kocienski Reaction of 2,2-Dimethoxyethyl PT Sulfone Followed by Acid Hydrolysis
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(E)-α,β-Unsaturated aldehydes were synthesized by the Julia-Kocienski reaction of 2,2-dimethoxyethyl 1-phenyl-1H-tetrazol-5-yl (PT) sulfone 3 with various aldehydes, followed by acid hydrolysis. The reaction could be carried out in one pot, and various (E)-α,β-unsaturated aldehydes were obtained in a short time and with high yields.
- Ando, Kaori,Watanabe, Haruka,Zhu, Xiaoxian
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p. 6969 - 6973
(2021/05/06)
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- Iron-Catalyzed ?±,?-Dehydrogenation of Carbonyl Compounds
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An iron-catalyzed α,β-dehydrogenation of carbonyl compounds was developed. A broad spectrum of carbonyls or analogues, such as aldehyde, ketone, lactone, lactam, amine, and alcohol, could be converted to their α,β-unsaturated counterparts in a simple one-step reaction with high yields.
- Zhang, Xiao-Wei,Jiang, Guo-Qing,Lei, Shu-Hui,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 1611 - 1615
(2021/03/03)
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- Selective aerobic oxidation of benzylic and allylic alcohols catalyzed by Cu(OAc)2/TEMPO/Et2NH
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Selective oxidation of benzylic and allylic alcohols to their corresponding aldehyde/ketone derivative without affecting saturated alcohols is still a challenging endeavor in organic synthesis. Various metal complexes, especially the copper complexes in the presence of TEMPO are being used very often for such transformations under aerobic conditions, but they are not selective to allylic and benzylic alcohols. The use of copper salt for oxidation of alcohols in the absence of a ligand are very scarcely studied except for the one catalyzed by CuCl/TEMPO where chloride inhibition and lack of selective oxidation have been noted upon use of CuCl2. Herein we report a Cu(OAc)2 catalyzed and TEMPO mediated selective aerobic oxidation of benzylic and allylic alcohols to aldehyde/ketone in the presence of Et2NH. The method avoids pre-synthesis of the catalyst as in the case of Cu(II)/(I) complexes/TEMPO catalyzed oxidation reactions, requires low catalyst loading, employs cheaper copper salt, and gives excellent selectivity for oxidation of benzylic and allylic alcohols.
- Bez, Ghanashyam,Gogoi, Achinta,Pasupuleti, Bala Gangadhar
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p. 589 - 597
(2021/09/28)
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- Zwitterion-induced organic-metal hybrid catalysis in aerobic oxidation
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In many metal catalyses, the traditional strategy of removing chloride ions is to add silver salts via anion exchange to obtain highly active catalysts. Herein, we reported an alternative strategy of removing chloride anions from ruthenium trichloride using an organic [P+-N-] zwitterionic compound via multiple hydrogen bond interactions. The resultant organic-metal hybrid catalytic system has successfully been applied to the aerobic oxidation of alcohols, tetrahydroquinolines, and indolines under mild conditions. The performance of zwitterion is far superior to that of many other common Lewis bases or Br?nsted bases. Mechanistic studies revealed that the zwitterion triggers the dissociation of chloride from ruthenium trichloride via nonclassical hydrogen bond interaction. Preliminary studies show that the zwitterion is applicable to catalytic transfer semi-hydrogenation.
- Hu, Rong-Bin,Lam, Ying-Pong,Ng, Wing-Hin,Wong, Chun-Yuen,Yeung, Ying-Yeung
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p. 3498 - 3506
(2021/04/07)
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- New method for promoting photosensitive oxidation to remove 1, 2-mercaptoethanol acetal protecting group by utilizing visible light irradiation
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The invention discloses a new method for removing a 1, 2-mercaptoethanol acetal protecting group, and belongs to the field of organic synthetic chemistry. The method comprises the following steps of:under a room-temperature open system, adding a substrate 2-substituted-1, 3-oxo-thio-cyclopentane and a catalytic amount of a photosensitizer Eosin Y into a proper amount of acetonitrile; and performing irradiating with a blue LED lamp for 3 hours while stirring to obtain the corresponding aldehyde compound with favorable yield. The method has the advantages of mild operation conditions, greenness, environmental protection, no harsh water and oxygen removal operation and device, realization of the reaction at room temperature, high substrate conversion rate, simple and easy post-treatment, andprovides a good method for removing the 1, 2-mercaptoethanol acetal protecting group at present.
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Paragraph 0014-0016
(2021/01/30)
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- Selective Rhodium-Catalyzed Hydroformylation of Terminal Arylalkynes and Conjugated Enynes to (Poly)enals Enabled by a π-Acceptor Biphosphoramidite Ligand
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The hydroformylation of terminal arylalkynes and enynes offers a straightforward synthetic route to the valuable (poly)enals. However, the hydroformylation of terminal alkynes has remained a long-standing challenge. Herein, an efficient and selective Rh-catalyzed hydroformylation of terminal arylalkynes and conjugated enynes has been achieved by using a new stable biphosphoramidite ligand with strong π-acceptor capacity, which affords various important E-(poly)enals in good yields with excellent chemo- and regioselectivity at low temperatures and low syngas pressures.
- Zhao, Jiangui,Zheng, Xueli,Tao, Shaokun,Zhu, Yuxin,Yi, Jiwei,Tang, Songbai,Li, Ruixiang,Chen, Hua,Fu, Haiyan,Yuan, Maolin
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supporting information
p. 6067 - 6072
(2021/08/16)
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- Method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and diphosphine ligand used in method
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The invention discloses a method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and a diphosphine ligand used in the method. According to the invention, indole-substituted phosphoramidite diphosphine ligand which is stable in air and insensitive to light is synthesized by utilizing a continuous one-pot method, and the indole-substituted phosphoramidite diphosphine ligand and a rhodium catalyst are used for jointly catalyzing to successfully achieve a hydroformylation reaction of aromatic terminal alkyne and terminal conjugated eneyne under the condition of synthesis gas for the first time, so that an olefine aldehyde structure compound can be rapidly and massively prepared, and particularly, a polyolefine aldehyde structure compound which is more difficult to synthesize in the prior art can be easily prepared and synthesized, and a novel method is provided for synthesis and modification of drug molecules, intermediates and chemical products.
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Paragraph 0118-0119
(2021/05/29)
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- Tandem oxidation-dehydrogenation of (hetero)arylated primary alcohols via perruthenate catalysis
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Tandem oxidative-dehydrogenation of primary alcohols to give a,b-unsaturated aldehydes in one pot are rare transformations in organic synthesis, with only two methods currently available. Reported herein is a novel method using the bench-stable salt methyltriphenylphosphonium perruthenate (MTP3), and a new co-oxidant NEMO&middoPF6 (NEMO = N-ethyl-N-hydroxymorpholinium) which provides unsaturated aldehydes in low to moderate yields. The Ley-Griffith oxidation of (hetero)arylated primary alcohols with N-oxide co-oxidants NMO (NMO = N-methylmorpholine N-oxide)/NEMO, is expanded by addition of the N-oxide salt NEMO&middoPF6 to convert the intermediate saturated aldehyde into its unsaturated counterpart. The discovery, method development, reaction scope, and associated challenges of this method are highlighted. The conceptual value of late-stage dehydrogenation in natural product synthesis is demonstrated via the synthesis of a polyene scaffold related to auxarconjugatin B.
- Bettencourt, Christian J.,Chow, Sharon,Moore, Peter W.,Read, Christopher D.G.,Jiao, Yanxiao,Bakker, Jan Peter,Zhao, Sheng,Bernhardt, Paul V.,Williams, Craig M.
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p. 652 - 659
(2021/09/08)
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- Sulfonium ion-promoted traceless Schmidt reaction of alkyl azides
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Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction through 1,2-migration of C-H and C-C bonds was accessible to the one-pot substitution reaction.
- Ardiansah, Bayu,Kakiuchi, Kiyomi,Morimoto, Tsumoru,Tanimoto, Hiroki,Tomohiro, Takenori
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supporting information
p. 8738 - 8741
(2021/09/08)
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- Substrate-Controlled Chemo-/Enantioselective Synthesis of α-Benzylated Enals and Chiral Cyclopropane-Fused 2-Chromanone Derivatives
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Substrate-controlled cascade reactions between α,β-unsaturated aldehydes or their analogues and 2,4-dinitrobenzyl chloride in the presence of a chiral secondary amine as the catalyst and base were developed, to obtain a broad spectrum of α-benzylated enals and enantioenriched cyclopropane-fused chroman-2-one derivatives. The cyclopropane-tethered iminium ion clearly served as a key intermediate in these reactions to trigger stereochemical outcomes, one of which was supported by a control experiment. (Figure presented.).
- Byeon, Huimyoung,Ryu, Sunghyeon,Yoo, Eun Jeong,Yang, Jung Woon
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supporting information
p. 5085 - 5091
(2021/09/20)
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- Enantioselective Organocatalytic Synthesis of 1,2,3-Trisubstituted Cyclopentanes
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An organocatalytic asymmetric domino Michael/α-alkylation reaction between enals and non-stabilized alkyl halides has been developed. Chiral secondary amine catalyzed cyclization reaction of 1-bromo-3-nitropropane with α,β-unsaturated aldehydes provides 1,2,3-trisubstituted cyclopentane carbaldehydes with high diastereo- (dr up to 8 : 1) and enantioselectivities (ee up to 96 %).
- ?otolová, Martina,Kamlar, Martin,Reme?, Marek,Géant, Pierre-Yves,Císa?ová, Ivana,?tícha, Martin,Vesely, Jan
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p. 5080 - 5089
(2021/09/30)
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- Rhodium-Catalyzed Regioselective Hydroformylation of Alkynes to α,β-Unsaturated Aldehydes Using Formic Acid
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A rhodium-catalyzed hydroformylation of alkynes with formic acid was developed. The method provides α,β-unsaturated aldehydes in high yield and E-selectivity without the need to handle toxic CO gas.
- Fan, Chao,Hou, Jing,Chen, Yu-Jia,Ding, Kui-Ling,Zhou, Qi-Lin
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supporting information
p. 2074 - 2077
(2021/04/05)
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- Saegusa Oxidation of Enol Ethers at Extremely Low Pd-Catalyst Loadings under Ligand-free and Aqueous Conditions: Insight into the Pd(II)/Cu(II)-Catalyst System
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A highly efficient and practical Pd(II)/Cu(OAc)2-catalyst system of Saegusa oxidation, which converts enol ethers to the corresponding enals with a number of diverse substrates at extremely low catalyst loadings (500 mol ppm) under ligand-free and aqueous conditions, is described. Its synthetic utility was demonstrated by large-scale applications of the catalyst system to important nature molecules. This work allows Saegusa oxidation to become a highly practical approach to preparing enals and also suggests new insight into the Pd(II)/Cu(II)-catalyst system for dehydrogenation of carbonyl compounds and decreasing Pd-catalyst loadings.
- Zhu, Quan,Luo, Yunsong,Guo, Yongyan,Zhang, Yushun,Tao, Yunhai
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p. 5463 - 5476
(2021/05/05)
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- B(C6F5)3-catalyzed tandem protonation/deuteration and reduction of: In situ -formed enamines
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A highly efficient B(C6F5)3-catalyzed tandem protonation/deuteration and reduction of in situ-formed enamines in the presence of water and pinacolborane was developed. Regioselective β-deuteration of tertiary amines was achieved with high chemo- and regioselectivity. D2O was used as a readily available and cheap source of deuterium. Mechanistic studies indicated that B(C6F5)3 could activate water to promote the protonation and reduction of enamines. This journal is
- Wu, Rongpei,Gao, Ke
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supporting information
p. 4032 - 4036
(2021/05/19)
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- Palladium-Catalyzed Diastereoselective Synthesis of (Z)-Conjugated Enynyl Homoallylic Alcohols
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The diastereoselective synthesis of anti-homoallylic alcohols bearing conjugated (Z)-enynes through a palladium-catalyzed three-component reaction is described. This reaction features a broad substrate scope, good functional group compatibility, and high levels of (Z)-alkene stereocontrol. In this reaction, Pd(0) functions as a catalyst in two fundamental steps of the tandem sequence: 1) the generation of a borylated π-allylpalladium species from bifunctional conjunctive reagents, inducing umpolung allylation of aldehydes, and 2) C(sp2)?C(sp) cross-coupling. Further transformations of the obtained products highlight their synthetic utility. (Figure presented.).
- Horino, Yoshikazu,Ishibashi, Mayo,Sakamoto, Juri,Murakami, Miki,Korenaga, Toshinobu
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supporting information
p. 3592 - 3599
(2021/06/15)
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- Visible light photoredox catalyzed deprotection of 1,3-oxathiolanes
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An efficient visible light photoredox catalyzed aerobic deprotection of 1,3-oxathiolanes using organic dye Eosin Y as a photocatalyst is disclosed. The deprotection procedure features the use of a metal-free catalyst, mild conditions, a broad range of substrate scope, and good functional group tolerance. 35 examples were tested under the standard conditions and most of them afforded the deprotected products in modest to high yields.
- Yang, Mingyang,Xing, Zhimin,Fang, Bowen,Xie, Xingang,She, Xuegong
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supporting information
p. 288 - 291
(2020/01/13)
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- Selective Reduction of α,β-Unsaturated Weinreb Amides in the Presence of α,β-Unsaturated Esters
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α,β-Unsaturated esters were selectively protected in situ in the presence of α,β-unsaturated Weinreb amides using PEt3 and trimethylsilyl trifluoromethanesulfonate (TMSOTf) in toluene under reflux. Diisobutylaluminium hydride (DIBAL-H) reduction of the mixture followed by tetra-n-butylammonium fluoride (TBAF) treatment produced α,β-unsaturated aldehydes in good yields along with the recovered α,β-unsaturated esters.
- Morita, Kenta,Murai, Kenichi,Arisawa, Mitsuhiro,Fujioka, Hiromichi
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p. 1100 - 1103
(2020/11/25)
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- Amino acid derivative, feed composition and application thereof
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The invention provides an amino acid derivative, a feed composition and application thereof, and belongs to the technical field of animal feed additives. The amino acid derivative is a compound with astructure shown as a formula (I), and a stereoisomer, a tautomer, a solvate, a metabolite, a feed acceptable salt or a prodrug thereof. In formula (I) shown in the specification, Z is a C1-C3 alkylene group. X is an indole ring group with a structure shown as a formula (II). The formula (II) is shown in the specification, wherein Y is phenyl with the structure shown in the formula (III) shown inthe specification. The amino acid derivative is used as an animal feed additive, and can promote the growth of animals and improve the feed conversion.
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- Visible-Light-Promoted Intramolecular α-Allylation of Aldehydes in the Absence of Sacrificial Hydrogen Acceptors
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We report herein an unprecedented protocol for radical cyclization of aldehydes with pendant alkenes via synergistic photoredox, cobaloxime, and amine catalysis. The transformation was achieved in the absence of external oxidants, providing a variety of 5-, 6-, and 7-membered ring products with alkene transposition in satisfactory yields. The reaction exhibits wide functional group compatibility and occurs under mild conditions with extrusion of H2.
- Liu, Feng,Liu, Jia-Li,tu, Jia-Lin
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supporting information
p. 7369 - 7372
(2020/10/05)
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- Deep eutectic solvent-catalyzed Meyer-Schuster rearrangement of propargylic alcohols under mild and bench reaction conditions
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The Meyer-Schuster rearrangement of propargylic alcohols into α,β-unsaturated carbonyl compounds has been revisited by setting up an atom-economic process catalyzed by a deep eutectic solvent FeCl3·6H2O/glycerol. Isomerizations take place smoothly, at room temperature, under air and with short reaction times. The unique solubilizing properties of the eutectic mixture enabled the use of a substrate concentration up to 1.0 M with the medium being recycled up to ten runs without any loss of catalytic activity. This journal is
- Ríos-Lombardía, Nicolás,Cicco, Luciana,Yamamoto, Kota,Hernández-Fernández, José A.,Morís, Francisco,Capriati, Vito,García-álvarez, Joaquín,González-Sabín, Javier
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supporting information
p. 15165 - 15168
(2020/12/21)
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- IBX-TfOH mediated oxidation of alcohols to aldehydes and ketones under mild reaction conditions
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An efficient, practical and facile procedure has been developed for the oxidation of primary and secondary alcohols using IBX-TfOH catalytic system in 1,4-dioxane at ambient temperature. The reaction affords quantitative yields of the corresponding carbonyl compounds without the formation of over oxidized products. The present synthetic protocol is compatible with a variety of substrates having arene, heteroarene and alkene functionalities. The developed synthetic protocol can be used for higher scale reactions as evident by the oxidation of alcohol at 1 g scale in higher yields by a simple filtration process.
- Kumar, Kamlesh,Kumar, Prashant,Joshi, Penny,Rawat, Diwan S
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supporting information
(2020/03/04)
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- Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3-Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses
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3-(Hetero)aryl propenals or propenones are efficiently prepared by a Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using Beller's CataCXium Ptb ligand under Jeffery's and Fu's conditions. The formation of these three-carbon building blocks is embedded into consecutive three- and pseudo-four-component syntheses of 3-(hetero)aryl and 3,5-diarylpyrazoles with a broad substitution pattern in moderate to excellent yield.
- Stephan, Marvin,Panther, Jesco,Wilbert, Fabio,Ozog, Pauline,Müller, Thomas J. J.
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supporting information
p. 2086 - 2092
(2020/03/23)
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- Palladium-Catalyzed [5 + 2] Annulation of Vinylethylene Carbonates with Barbiturate-Derived Alkenes
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A palladium/XantPhos-catalyzed [5 + 2] annulation of VECs with electron-deficient alkenes having an isolated carbon-carbon double bond has been developed to afford spirobarbiturate-tetrahydrooxepines. This study provides an expedient assembly of biologically interesting spirobarbiturate-tetrahydrooxepines. The easy scalability and versatile transformability of the reaction products were also exhibited.
- Chen, Yuehua,Deng, Hao,Gao, Xing,Guo, Hongchao,Jiang, Feng,Wang, Wei,Wu, Yongjun,Zhu, Dongyu
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supporting information
p. 7158 - 7163
(2020/10/02)
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- Concurrent Formation of N-H Imines and Carbonyl Compounds by Ruthenium-Catalyzed C-C Bond Cleavage of β-Hydroxy Azides
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A commercial cyclopentadienylrutenium dicarbonyl dimer ([CpRu(CO)2]2) efficiently catalyzes the formation of N-H imines and carbonyl compounds simultaneously from β-hydroxy azides via C-C bond cleavage under visible light. Density functional theory calculations for the cleavage reaction support the mechanism involving chelation of alkoxy azide species and liberation of nitrogen as the driving force. The synthetic utility of the reaction was demonstrated by a new amine synthesis promoted by chemoselective allylation of imine and synthesis of isoquinoline.
- Lee, Jeong Min,Bae, Dae Young,Park, Jin Yong,Jo, Hwi Yul,Lee, Eunsung,Rhee, Young Ho,Park, Jaiwook
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p. 4608 - 4613
(2020/06/05)
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- Iron(III)/O2-Mediated Regioselective Oxidative Cleavage of 1-Arylbutadienes to Cinnamaldehydes
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A simple, efficient, and environmentally benevolent regioselective oxidative cleavage of 1-arylbutadienes to cinnamaldehydes mediated by iron(III) sulfate/O2 has been developed. The reaction offered good yields and excellent regioselectivity and showed good functional group tolerance (31 examples). The method is important, as few reports with limited substrate scope are available for such excellent oxidative cleavage of conjugated dienes.
- Bhowmik, Amit,Fernandes, Rodney A.
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p. 9203 - 9207
(2019/11/14)
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- Highly γ-Regioselective 1,2-Addition of α,β-Unsaturated Oxime Ethers with Allylzinc Bromides: A Straightforward Approach for the Synthesis of Homoallylic Amines
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A highly regioselective reaction between allylzinc bromide reagents and α,β-unsaturated oxime ethers for the one-step synthesis of the homoallylic amines is reported. This process is a regioselective 1,2-addition reaction providing a new γ-position with carbon-carbon bond formation. Furthermore, the reaction substrates are widely applicable and can be produced in a high yield.
- Yang, Bo,Zhang, Songlin
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supporting information
p. 3736 - 3746
(2019/09/30)
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- Phosphorous acid promoted isomerization of propargyl alcohols to α,β-unsaturated carbonyl compounds
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A metal-free and two-phase protocol for the Meyer-Schuster isomerization of propargyl alcohols to the corresponding α,β-unsaturated carbonyl compounds has been achieved in the presence of stoichiometric phosphorous acid aqueous solution, which produces the desired products in high yields with excellent stereoselectivity. Compared with the traditional methods, the procedure features broad scope of the substrates, mild conditions, and easy separation, providing an appealing alternative to the Meyer-Schuster reaction.
- Gan, Xiaotang,Fu, Zuqi,Liu,Yan, Yani,Chen, Chao,Zhou, Yongbo,Dong, Jianyu
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- Highly efficient and practical aerobic oxidation of alcohols by inorganic-ligand supported copper catalysis
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The oxidation of alcohols to aldehydes or ketones is a highly relevant conversion for the pharmaceutical and fine-chemical industries, and for biomass conversion, and is commonly performed using stoichiometric amounts of highly hazardous oxidants. The aerobic oxidation of alcohols with transition metal complex catalysts previously required complicated organic ligands and/or nitroxyl radicals as co-catalysts. Herein, we report an efficient and eco-friendly method to promote the aerobic oxidation of alcohols using an inorganic-ligand supported copper catalyst 1, (NH4)4[CuMo6O18(OH)6], with O2 (1 atm) as the sole oxidant. Catalyst 1 is synthesized directly from cheap and commonly available (NH4)6Mo7O24·4H2O and CuSO4, which consists of a pure inorganic framework built from a central CuII core supported by six MoVIO6 inorganic scaffolds. The copper catalyst 1 exhibits excellent selectivity and activity towards a wide range of substrates in the catalytic oxidation of alcohols, and can avoid the use of toxic oxidants, nitroxyl radicals, and potentially air/moisture sensitive and complicated organic ligands that are not commercially available. Owing to its robust inorganic framework, catalyst 1 shows good stability and reusability, and the catalytic oxidation of alcohols with catalyst 1 could be readily scaled up to gram scale with little loss of catalytic activity, demonstrating great potential of the inorganic-ligand supported Cu catalysts in catalytic chemical transformations.
- Wei, Zheyu,Ru, Shi,Zhao, Qixin,Yu, Han,Zhang, Gang,Wei, Yongge
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supporting information
p. 4069 - 4075
(2019/08/07)
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- Acyl/aroyl Meldrum's acid as an enol surrogate for the direct organocatalytic synthesis of α,β-unsaturated ketones
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The operationally simple, robust and straightforward organocatalytic protocol is developed for the synthesis of E-selective α,β-unsaturated ketones. The method utilizes simple and easily accessible starting materials such as Meldrum's acid, carboxylic acid, aldehyde and simple bifunctional amine catalyst. The tandem organocatalytic process utilizes acyl/aroyl Meldrum's acid as an enol surrogate for the effective Doebner-Knoevenagel type condensation reactions. A wide variety of aldehydes, carboxylic acids and base sensitive functional groups are well tolerated under the mild reaction conditions.
- Khopade, Tushar M.,Warghude, Prakash K.,Mete, Trimbak B.,Bhat, Ramakrishna G.
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supporting information
p. 197 - 200
(2018/12/13)
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- Donor Rhodium Carbenes by Retro-Buchner Reaction
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Rhodium carbenes are key intermediates in a range of cycloadditions and insertion reactions. Herein, we report the first generation of donor RhII carbenes by decarbenation of 7-substituted 1,3,5-cycloheptatrienes. This discovery unlocks an improved retro-Buchner-cyclopropanation sequence, a Si?H insertion reaction for a broad-scope synthesis of allylsilanes, and a new method for the vinylogation of aldehydes. The last strategy led to the development of an iterative synthesis of E-polyenes, and to the total synthesis of navenones B and C.
- Mato, Mauro,Echavarren, Antonio M.
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supporting information
p. 2088 - 2092
(2019/01/25)
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- Dehydrogenative β-Arylation of Saturated Aldehydes Using Transient Directing Groups
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An unprecedented cross-dehydrogenative-coupling (CDC) reaction of saturated aldehyde β-C-H with arenes to form cinnamaldehydes via the cleavages of four C-H bonds has been developed. The reaction possesses complete E-stereoselectivity for the C=C double bond. The protocol is featured by atom and step economy, mild reaction conditions, and convenient operation.
- Zhang, Xing-Long,Pan, Gao-Fei,Zhu, Xue-Qing,Guo, Rui-Li,Gao, Ya-Ru,Wang, Yong-Qiang
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supporting information
p. 2731 - 2735
(2019/04/30)
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- Towards Mechanistic Understanding of Liquid-Phase Cinnamyl Alcohol Oxidation with tert-Butyl Hydroperoxide over Noble-Metal-Free LaCo1–xFexO3 Perovskites
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Noble-metal-free perovskite oxides are promising and well-known catalysts for high-temperature gas-phase oxidation reactions, but their application in selective oxidation reactions in the liquid phase has rarely been studied. We report the liquid-phase oxidation of cinnamyl alcohol over spray-flame synthesized LaCo1–xFexO3 perovskite nanoparticles with tert-butyl hydroperoxide (TBHP) as the oxidizing agent under mild reaction conditions. The catalysts were characterized by XRD, BET, EDS and elemental analysis. LaCo0.8Fe0.2O3 showed the best catalytic properties indicating a synergistic effect between cobalt and iron. The catalysts were found to be stable against metal leaching as proven by hot filtration, and the observed slight deactivation is presumably due to segregation as determined by EDS. Kinetic studies revealed an apparent activation energy of 63.6 kJ mol?1. Combining kinetic findings with TBHP decomposition as well as control experiments revealed a complex reaction network.
- Waffel, Daniel,Alkan, Baris,Fu, Qi,Chen, Yen-Ting,Schmidt, Stefan,Schulz, Christof,Wiggers, Hartmut,Muhler, Martin,Peng, Baoxiang
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p. 1155 - 1163
(2019/09/06)
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- Enzymatic One-Step Reduction of Carboxylates to Aldehydes with Cell-Free Regeneration of ATP and NADPH
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The direct generation of aldehydes from carboxylic acids is often a challenging synthetic task but undoubtedly attractive in view of abundant supply of such feedstocks from nature. Though long known, biocatalytic carboxylate reductions are at an early stage of development, presumably because of their co-factor requirement. To establish an alternative to whole-cell-based carboxylate reductions which are limited by side reactions, we developed an in vitro multi-enzyme system that allows for quantitative reductions of various carboxylic acids with full recycling of all cofactors and prevention of undesired over-reductions. Regeneration of adenosine 5′-triphosphate is achieved through the simultaneous action of polyphosphate kinases from Meiothermus ruber and Sinorhizobium meliloti and β-nicotinamide adenine dinucleotide 2′-phosphate is reduced by a glucose dehydrogenase. Under these conditions and in the presence of the carboxylate reductases from Neurospora crassa or Nocardia iowensis, various aromatic, heterocyclic and aliphatic carboxylic acids were quantitatively reduced to the respective aldehydes.
- Strohmeier, Gernot A.,Eitelj?rg, Inge C.,Schwarz, Anna,Winkler, Margit
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p. 6119 - 6123
(2019/04/13)
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- Magnetic crosslinked copoly(ionic liquid) nanohydrogel supported palladium nanoparticles as efficient catalysts for the selective aerobic oxidation of alcohols
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Nowadays it is still a great sustainable processes challenge to produce efficient, selective and easy magnetic recovery and recycling catalysts for oxidation of alcohols using air as the oxidant. In this work, a new magnetic nanohydrogel comprising [DABCO-allyl][Br] ionic liquid, allyl alcohol and N,N’-methylenebis(acrylamide) is used for stabilization of small and highly uniform palladium nanoparticles of 3–4 nm size MXCPILNHG@Pd. This material has been characterized by Fourier-transform infrared spectroscopy (FTIR), atomic adsorption spectroscopy (AAS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), SEM-Map, energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectra (XPS), vibrating-sample magnetometer (VSM) and dynamic light scattering (DLS). According to optimization of cross-linking degree and ratio of DABCO-IL, MXCPILNHG-2@Pd is found as a highly selective catalyst in oxidations of primary alcohols to the corresponding aldehydes in toluene and to acids in water. Furthermore, secondary alcohols were reacted efficiently to the corresponding ketones in both toluene and water. Catalyst is magnetically recovered and recycled for several times in both toluene and water and the reused catalysts are characterized by TEM and XPS.
- Gholinejad, Mohammad,Afrasi, Mahmoud,Nikfarjam, Nasser,Nájera, Carmen
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p. 185 - 195
(2018/07/14)
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- Palladium-Catalyzed Regioselective Aerobic Allylic C?H Oxygenation: Direct Synthesis of α,β-Unsaturated Aldehydes and Allylic Alcohols
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A protocol for the synthesis of α,β-unsaturated aldehydes and allylic alcohols from simple allylic hydrocarbons with water via palladium-catalyzed functionalization of allylic C?H bonds was described. Molecular oxygen is utilized as the sole oxidant in this oxygenation of terminal alkenes. This protocol features good functional group compatibility, broad substrate scope, and high atom- and step-economy. Moreover, the synthetic utility of this method can be highlighted by its application to the synthesis of ibuprofen, which is a highly potent analgesic. (Figure presented.).
- Li, Chunsheng,Chen, Huoji,Li, Jianxiao,Li, Meng,Liao, Jianhua,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 1600 - 1604
(2018/03/05)
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- Modular synthesis of (E)-cinnamaldehydes directly from allylarenes via a metal-free DDQ-mediated oxidative process
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An efficient synthesis of (E)-cinnamaldehydes by a metal-free DDQ-mediated oxidative transformation of allylarenes was developed. The protocol provides a practical method to prepare diverse (E)-cinnamaldehydes with broad functional group tolerance in good to excellent yields, including easy access to natural products randainal and geranyloxy sinapyl aldehyde from plant extracts. Finally, the mechanism of a single-electron transfer process was proposed.
- Xu, Ting-Ting,Jiang, Tao-Shan,Han, Xiao-Lan,Xu, Yuan-Hong,Qiao, Jin-Ping
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p. 5350 - 5358
(2018/08/03)
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- Synthesis of Enones and Enals via Dehydrogenation of Saturated Ketones and Aldehydes
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A general, efficient and economic palladium-catalyzed dehydrogenation to form enones or enals has been developed. The approach possesses extremely broad substrate scope including various linear or cyclic saturated ketones and aldehydes. The protocol is ligand-free, and molecular oxygen is used as the sole clean oxidant in the reaction. Due to mild reaction conditions, good functional group compatibility, and versatile utilities of enones and enals, the method can be applied in the late-stage synthesis of natural products, pharmaceuticals and fine chemicals. (Figure presented.).
- Pan, Gao-Fei,Zhu, Xue-Qing,Guo, Rui-Li,Gao, Ya-Ru,Wang, Yong-Qiang
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p. 4774 - 4783
(2018/11/10)
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- Hendrickson reagent induced rearrangement of aryl propargyl alcohols to α,β-unsaturated aldehydes
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The Hendrickson reagent (triphenylphosphonium anhydride trifluoromethanesulfonate), prepared from the reaction of triphenylphosphine oxide (Ph3PO) and triflic anhydride (Tf2O) (2:1 stoichiometry), promotes dehydrations and various coupling reactions. The reagent has been used to transform oximes to nitriles and to prepare esters, amides and many other functional groups through the intermediacy of an alkoxyphosphonium salt. The reagent proved useful in heterocycle synthesis of thiazolines, imidazolines, quinoline precursors, isoquinolines, β-carbolines, phenanthridines, 11H-indolo[3,2-c]quinolines, quinoline-lactones, furoquinolinones, and indolizino[1,2-b]quinolin-9(11H)-ones. Moreover, the reagent has been key to the successful total synthesis of several natural products. Aryl propargyl alcohols with a terminal α-acetylenic group undergo rapid conversion to the corresponding α,β-unsaturated aldehydes at room temperature in dichloromethane in the presence of one equivalent of triphenylphosphonium anhydride trifluoromethanesulfonate. The reaction involved adding freshly distilled Tf2O (1.0 mmol) to a solution of Ph3PO (2.0 mmol) in CH2Cl2 (10 mL) at 0oC under N2 atmosphere. After stirring for 10 min, the propargyl alcohol (1.0 mmol) was added as a CH2Cl2 solution (2 mL), followed by the addition of water and Et3N (2.0 mmol) and further stirring at room temperature for 1h. Subsequent workup with 5% NaHCO3 (20 mL) and purification afforded α,β-unsaturated aldehydes. Eighteen aryl propargyl alcohol substrates with a terminal α-acetylenic group were transformed in good to excellent yields (71-85%) to enals. The methodology proved successful with secondary and tertiary alcohols with stereoselectivity favouring exclusively the E isomer. All the synthesized compounds are known and were characterized (1H,13C, and M.P) and compared to literature values. The method offers several advantages such as exclusive stereoselectivity, short reaction time, good yield, mild reaction conditions, and simple operational procedure.
- Moussa, Ziad,Aljuhani, Ateyatallah
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p. 845 - 853
(2018/11/06)
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- Cu2 O/monodentate ligand/TEMPO by catalyzing air production of aldehydes
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The invention discloses a Cu2 O/monodentate ligand/TEMPO by catalyzing air production of aldehydes, characterized in that incendiary as raw materials, air as the oxidizing agent, to the organic solution as the solvent, in the Cu2 S/monodentate ligand/TEMPO under the catalytic action, modifiable is oxidized to obtain corresponding aldehydes; the catalyst of the invention not only has excellent catalytic activity of the catalytic system at the same time recycled; and simplify the catalytic system, the operation is simple, the substrate serviceability is good, high yield, low cost.
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Paragraph 0029; 0030; 0050
(2019/01/08)
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- An efficient and sustainable protocol for oxidation of alcohols to carbonyl compounds
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A simple and extremely efficient protocol is developed for oxidation of alcohols to carbonyl compounds at room temperature by using green solvent lactic acid and green oxidant H2O2. This protocol provides high conversion under catalyst free conditions. The easy work up procedure allows high selectivity and good to excellent yields of carbonyl compounds with purity. We have performed wide range of substrates in present study with primary focus on reusability of lactic acid.
- Wagh, Ravindra B.,Nagarkar, Jayashree M.
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supporting information
p. 3443 - 3447
(2018/08/20)
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- Phosphine-mediated partial reduction of alkynes to form both (E)- and (Z)-alkenes
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A mild, phosphine-mediated partial reduction of alkynyl carbonyls to the corresponding alkenes was developed. Tuning of the reaction conditions led to either the (E)- or (Z)-diastereomer with high selectivity. A range of alkynyl esters, amides, and ketones were reduced to form alkenes in good to high yields and with excellent functional group tolerance.
- Pierce, Brett M.,Simpson, Brittany F.,Ferguson, Kane H.,Whittaker, Rachel E.
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supporting information
p. 6659 - 6662
(2018/09/29)
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- Well-Defined Rhodium-Gallium Catalytic Sites in a Metal-Organic Framework: Promoter-Controlled Selectivity in Alkyne Semihydrogenation to E-Alkenes
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Promoters are ubiquitous in industrial heterogeneous catalysts. The wider roles of promoters in accelerating catalysis and/or controlling selectivity are, however, not well understood. A model system has been developed where a heterobimetallic active site comprising an active metal (Rh) and a promoter ion (Ga) is preassembled and delivered onto a metal-organic framework (MOF) support, NU-1000. The Rh-Ga sites in NU-1000 selectively catalyze the hydrogenation of acyclic alkynes to E-alkenes. The overall stereoselectivity is complementary to the well-known Lindlar's catalyst, which generates Z-alkenes. The role of the Ga in promoting this unusual selectivity is evidenced by the lack of semihydrogenation selectivity when Ga is absent and only Rh is present in the active site.
- Desai, Sai Puneet,Ye, Jingyun,Zheng, Jian,Ferrandon, Magali S.,Webber, Thomas E.,Platero-Prats, Ana E.,Duan, Jiaxin,Garcia-Holley, Paula,Camaioni, Donald M.,Chapman, Karena W.,Delferro, Massimiliano,Farha, Omar K.,Fulton, John L.,Gagliardi, Laura,Lercher, Johannes A.,Penn, R. Lee,Stein, Andreas,Lu, Connie C.
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supporting information
p. 15309 - 15318
(2018/11/30)
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- Palladium-Catalyzed Formylation of Alkenylzinc Reagents with S-(4-Nitrophenyl) Thioformate
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We report the synthesis of enal compounds by palladium-catalyzed formylation of alkenylzinc reagents with S-(4-nitrophenyl) thioformate. Various functional groups were tolerated in the present reaction. 1H NMR experiments revealed that the products had a non-protected formyl group, which can be utilized for further C–C bond formation reactions. We successfully achieved the one-pot synthesis of a 1,5-diene-3-ol compound via sequential formylation and allylation.
- Haraguchi, Ryosuke,Tanazawa, Sho-Go,Tokunaga, Naoya,Fukuzawa, Shin-Ichi
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p. 1761 - 1764
(2018/04/27)
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- Palladium-Catalyzed Reductive Conversion of Acyl Fluorides via Ligand-Controlled Decarbonylation
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Ligand-controlled non-decarbonylative and decarbonylative conversions of acyl fluorides were developed using a Pd(OAc)2/Et3SiH combination. When tricyclohexylphosphine (PCy3) was used as the ligand, aldehydes were obtained as simple reductive conversion products. The use of 1,2-bis(dicyclohexylphosphino)ethane (Cy2P(CH2)2PCy2, DCPE) as the ligand, however, favored the formation of hydrocarbons, which are decarbonylative reduction products.
- Ogiwara, Yohei,Sakurai, Yuka,Hattori, Hiroyuki,Sakai, Norio
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supporting information
p. 4204 - 4208
(2018/07/29)
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- Bio-derived production of cinnamyl alcohol: Via a three step biocatalytic cascade and metabolic engineering
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The construction of biocatalytic cascades for the production of chemical precursors is fast becoming one of the most efficient approaches to multi-step synthesis in modern chemistry. However, despite the use of low solvent systems and renewably resourced catalysts in reported examples, many cascades are still dependent on petrochemical starting materials, which as of yet cannot be accessed in a sustainable fashion. Herein, we report the production of the versatile chemical building block cinnamyl alcohol from the primary metabolite and the fermentation product l-phenylalanine. Through the combination of three biocatalyst classes (phenylalanine ammonia lyase, carboxylic acid reductase and alcohol dehydrogenase) the target compound could be obtained in high purity, demonstrable at the 100 mg scale and achieving 53% yield using ambient temperature and pressure in an aqueous solution. This system represents a synthetic strategy in which all components present at time zero are biogenic and thus minimises damage to the environment. Furthermore we extend this biocatalytic cascade by its inclusion in an l-phenylalanine overproducing strain of Escherichia coli. This metabolically engineered strain produces cinnamyl alcohol in mineral media using glycerol and glucose as the carbon sources. This study demonstrates the potential to establish green routes to the synthesis of cinnamyl alcohol from a waste stream such as glycerol derived, for example, from lipase treated biodiesel.
- Klumbys, Evaldas,Zebec, Ziga,Weise, Nicholas J.,Turner, Nicholas J.,Scrutton, Nigel S.
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supporting information
p. 658 - 663
(2018/02/14)
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- Secondary amine-catalyzed [3 + 3] benzannulation to access polysubstituted benzenes through iminium activation
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An organocatalytic [3 + 3] benzannulation to access polysubstituted benzenes from readily available α,β-unsaturated aldehydes and 1,3-bis(phenylsulfonyl)propene or 4-sulfonylcrotonates is described. The key reaction step is considered to be the iminium ac
- Jiang, Lin,Li, Hang,Zhou, Jiang-Feng,Yuan, Ming-Wei,Li, Hong-Li,Chuan, Yong-Ming,Yuan, Ming-Long
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supporting information
p. 336 - 343
(2018/02/09)
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- Palladium-catalyzed hydroformylation of terminal arylacetylenes with glyoxylic acid
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A simple, practical and governable palladium-catalyzed hydroformylation of terminal arylacetylenes has been disclosed. The reaction proceeds under syngas-free conditions, using readily available glyoxylic acid as the formyl source, under mild conditions, giving rise to a broad range of α,β-unsaturated aldehydes.
- Liu, Yang,Cai, Liangzhen,Xu, Sheng,Pu, Weiwen,Tao, Xiaochun
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supporting information
p. 2166 - 2168
(2018/03/06)
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