105-13-5Relevant articles and documents
Isochroman-3-ones ones via site-selective ring opening of benzocyclobutenones promoted by lithium tetramethylpiperidide and reaction with aromatic aldehydes
Matsumoto, Takashi,Hamura, Toshiyuki,Kuriyama, Yokusu,Suzuki, Keisuke
, p. 8985 - 8988 (1997)
In the presence of Li-TMP and an aromatic aldehyde, benzocyclobutenone undergoes an unusual heterolytic C(1)-C(4) bond fission, and subsequent reaction with the aldehyde gives, after acidic workup, isochroman-3-one in high yield.
Comparative study on reducing aromatic aldehydes by using ammonia borane and lithium amidoborane as reducing reagents
Xu, Weiliang,Fan, Hongjun,Wu, Guotao,Chen, Ping
, p. 1496 - 1501 (2012)
Lithium amidoborane (LiNH2BH3) and ammonia borane (NH3BH3) reduce aromatic aldehydes in tetrahydrofuran (THF) through two different pathways. LiNH2BH3 only transfers hydridic hydrogen on boron to aldehydes through a hydroboration process to achieve lithium aminoborate; ammonia borane, on the other hand, transfers both protic and hydridic hydrogens on N and B, respectively, to aldehydes to directly achieve corresponding alcohols. Mechanistic investigations confirm that protic H(N) and hydridic H(B) of ammonia borane participate in the reduction, in which the dissociation of both B-H and N-H bonds is likely to be involved in the rate-determining step. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.
Homoleptic Zinc-Catalyzed Hydroboration of Aldehydes and Ketones in the Presence of HBpin
Kumar, Gobbilla Sai,Harinath, Adimulam,Narvariya, Rajrani,Panda, Tarun K.
, p. 467 - 474 (2020)
Here, we report the reaction between N-phenyl-o-phenylenediamine and pyrrole-2-carboxaldehyde to afford the N-phenyl-o-phenyl-enediiminopyrrole ligand {L-H2} in quantitative yield. A one-pot reaction between {L-H2} and diethylzinc (ZnEt2) in a 2:1 ratio afforded the homoleptic zinc metal complex [{L-H}2Zn] (1). The solid-state structures of ligand {L-H2} and zinc complex 1 were confirmed using X-ray crystallography. Further, complex 1 was used for chemoselective hydroboration of aldehydes and ketones in the presence of pinacolborane (HBpin) at ambient temperature to produce the corresponding boronate esters in high yield.
Arylboronic acid-facilitated selective reduction of aldehydes by tributyltin hydride
Yu,Wang
, p. 2719 - 2725 (2001)
Aldehydes were selectively reduced in the presence of a ketone with tributyltin hydride (n-Bu3SnH) and arylboronic acids. The double bond of an α-β-unsaturated system was not affected under the reaction conditions.
High loading polymer reagents based on polycationic Ultraresins. Polymer-supported reductions and oxidations with increased efficiency
Barth, Michael,Shah, Syed Tasadaque Ali,Rademann, J?rg
, p. 8703 - 8709 (2004)
Ultraresin 1 was prepared from highly branched polyethylene imine (M n=10,000) via reductive cross-linking with terephthaldialdehyde. Following quaternization with methyl iodide, the polycationic Ultraresin 2, with iodide as a counterion, was obtained. These novel resins combine low swelling with high mechanical stability. By anion exchange polycationic Ultraresins carrying borohydride (3) and periodate (22) were generated and were investigated as very high loading polymer reagents. Ultra-borohydride resin 3 had a reducing activity of up to 12 mmol/g depending on the substrate. It proved successful in diverse reductions including those of aldehydes, ketones, and nitroolefines. The resin was employed in the reductive amination of aldehydes with an excess of amines, which were removed by the use of a scavenger resin. Periodate resin 22 was obtained with an active loading of up to 5.4 mmol/g and was employed in oxidations of sulfides, diols, hydroquinones, and hydrazines.
A convenient nickel-catalysed hydrosilylation of carbonyl derivatives
Zheng, Jianxia,Darcel, Christophe,Sortais, Jean-Baptiste
, p. 81 - 84 (2013)
Hydrosilylation of aldehydes and ketones catalysed by nickel acetate and tricyclohexylphosphine as the catalytic system was demonstrated using polymethylhydrosiloxane as a cheap reducing reagent. The Royal Society of Chemistry 2013.
An Efficient, Stable and Reusable Palladium Nanocatalyst: Chemoselective Reduction of Aldehydes with Molecular Hydrogen in Water
Kotha, Surya Srinivas,Sharma, Nidhi,Sekar, Govindasamy
, p. 1694 - 1698 (2016)
Palladium nanoparticles (Pd-BNP) stabilized by a binaphthyl-backbone can be efficiently used for the chemoselective reduction of aldehydes in the presence of hydrogen at room temperature in water. The Pd-BNP catalyst is easily recovered and reused for five catalytic cycles. (Figure presented.).
In pursuit of fluorinated sigma receptor ligand candidates related to [18F]-FPS
Jwad, Rasha S.,Pang, Alan H. C.,Hunter, Luke,Read, Roger W.
, p. 213 - 225 (2019)
This paper describes the synthesis of N-arylmethyl(1-benzyl) and N-aroyl(1-benzoyl) 4-(4-fluoromethylphenoxymethyl)piperidines as potential sigma receptor ligands analogous to the potent and highly selective sigma-1 ligand [18F]-FPS, but with enhanced or alternative binding and transport profiles. The synthesis involves N-aroylation of 4-hydroxmethylpiperidine or ethyl nipecotate, functional group manipulation of the ester group or simple activation of the hydroxyl group to introduce the phenoxy component, and subsequent functional group manipulation to reduce the amide group and introduce the fluorine into the fluoromethyl substituent. In its development, the synthesis was found to require early N-aroylation of the piperidine precursor to avoid complications due to anchimeric assistance by its nitrogen in subsequent displacement reactions. New evidence is presented on the pathway followed in a literature report of direct displacement of a benzylic hydroxyl group by fluoride ion under Appel-like conditions. Relevant to the literature report, the halide ion in the fluoromethylphenoxy 1-benzylpiperidine derivatives was surprisingly labile to hydrolytic displacement on chromatography and this aspect is worthy of further study. Moreover, the NMR spectra of the amides were complicated by geometric isomerism about the amide C(O)-N bond, but detailed analysis of spectra from 2-anisoyl derivatives allowed the assignment of diastereomeric contributors to consistent, secondary atropisomerism about the aryl-C(O) bond.
Solvolytic Reactions in Fluorinated Alcohols. Role of Nucleophilic and Other Solvation Effects
Bentley, T. William,Llewellyn, Gareth,Ryu, Zoon Ha
, p. 4654 - 4659 (1998)
Rate constants and products for solvolyses of chlorodiphenylmethane (Ph2CHCl) and p-methoxybenzyl chloride in 2,2,2-trifluoroethanol (TFE)/water and TFE/ethanol are reported, along with additional kinetic data for solvolyses of tert-butyl and other alkyl halides (RX) in 97% w/w TFE/water and in 97% w/w hexafluoropropan-2-ol/water (HFIP). Results are discussed in terms of the solvent ionizing power (Y) and the solvent nucleophilicity (N), and contributions from other solvation effects are considered. Comparisons with other SN1 solvolyses show that solvolyses of Ph2CHCl in TFE mixtures are unexpectedly fast, but product ratios are unexceptional. An additional solvation effect influences solvolyses leading to delocalized cations, and a delocalized cationic transition state for concerted elimination may explain the recent results of Takeuchi et al., (J. Org. Chem. 1997, 62, 4904) without the need to postulate additional specific solvation effects for adamantyl systems, such as Bronsted-base solvation of α- and β-hydrogen atoms; concerted elimination may occur because simple tertiary alkyl cations are too unstable to form in predominantly aqueous media. Iodide/bromide and bromide/chloride rate ratios are very similar for 1-adamantyl halides and corresponding solvolyses of tert-butyl halides; these ratios decrease in the order aq EtOH > TFE > HFIP, as expected for an electrophilic solvation effect (this effect can readily be incorporated into Y values). From kinetic data for a series of tertiary alkyl chlorides in 97% TFE/water, it is shown that the susceptibility of rates of solvolyses of RCl to N decreases with an increase in steric hindrance or with an increase in charge stabilization. Also, the small kinetic solvent isotope effects for typical solvolyses (e.g., methyl tosylate) indicate that nucleophilic attack lags behind heterolysis of the C-X bond.
Hydrosilylation of aldehydes and ketones catalyzed by [Ph3P(CuH)]6
Lipshutz, Bruce H.,Chrisman, Will,Noson, Kevin
, p. 367 - 371 (2001)
Exposure of an aldehyde or ketone to ≤ 5 mol% (in copper) of Stryker's reagent [Ph3P(CuH)]6 in the presence of one of several silanes affords the corresponding protected alcohol in high yields. Aldehydes can be cleanly reduced in the presence of ketones.
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Shimazono,Nord
, (1960)
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Wet THF as a suitable solvent for a mild and convenient reduction of carbonyl compounds with NaBH4
Zeynizadeh, Behzad,Behyar, Tarifeh
, p. 307 - 315 (2005)
NaBH4 in wet THF can readily reduce varieties of carbonyl compounds such as aldehydes, ketones, conjugated enones, acyloins, and α-diketones to their corresponding alcohols in good to excellent yields. Reduction reactions were performed at room temperature or under reflux condition. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing system.
Oxidation of Benzyltrialkylstannanes by Iodosylbenzene Catalyzed by Iron Tetrakis(pentafluorophenyl)porphyrin Chloride. Possible Role of Benzyloxy Radicals
Baciocchi, Enrico,Ioele, Marcella
, p. 5504 - 5508 (1995)
The oxidations of some benzyltrialkylstannanes by iodosylbenzene induced by tetrakis(pentafluorophenyl)porphyrin chloride (TPFP)FeCl have been investigated.Benzaldehydes and benzyl alcohols are the main reaction products, accompanied by minor amounts of 1,2-diarylethanes and benzyl chlorides.A mechanism seems likely involving the formation of a benzyltrialkylstannane cation radical, which undergoes C-Sn bond cleavage to afford a benzyl radical.The formation of 1,2-diarylethane from this radical is straightforward, whereas it is suggested that benzyl alcohol and benzaldehyde result from the disproportionation of a benzyloxy radical, formed in a oxygen transfer reaction from iodosylbenzene to the benzyl radical.In CH2Cl2, benzyl alcohol can also be the result of hydrogen atom abstraction from the solvent by the benzyloxy radical.
Late-Stage Solubilization of Poorly Soluble Peptides Using Hydrazide Chemistry
Sato, Kohei,Tanaka, Shoko,Wang, Junzhen,Ishikawa, Kenya,Tsuda, Shugo,Narumi, Tetsuo,Yoshiya, Taku,Mase, Nobuyuki
, p. 1653 - 1658 (2021)
A novel late-stage solubilization of peptides using hydrazides is described. A solubilizing tag was attached through a selective N-alkylation at a hydrazide moiety with the aid of a 2-picoline-borane complex in 50% acetic acid-hexafluoro-2-propanol. The tag, which tolerates ligation and desulfurization conditions, can be detached by a Cu-mediated selective oxidative hydrolysis of the N-alkyl hydrazide. This new method was validated through the synthesis of HIV-1 protease.
(PhCH2PPh3)+Br3-: A versatile reagent for the preparation, deprotection, and oxidation of trimethylsilyl ethers
Shirini,Imanzadeh,Mousazadeh,Mohammadpoor-Baltork,Aliakbar,Abedini
, p. 641 - 646 (2010)
Benzyltriphenylphosphonium tribromide (BTPTB), as a stable solid reagent, is easily prepared by the reaction of benzyltriphenylphosphonium bromide with Br2. This reagent can be used as an efficient catalyst for the conversion of alcohols to their corresponding trimethylsilyl ethers (TMS ethers) with hexamethyldisilazane (HMDS). Desilylation of TMS ethers is also catalyzed by BTPTB in MeOH at room temperature in high yields. BTPTB is also able to oxidize the TMS ethers to their corresponding carbonyl compounds in a mixture of MeOH/H2O in good to high yields. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.
A new alternative to Stryker's reagent in hydrosilylation: Synthesis, structure, and reactivity of a well-defined carbene-copper(II) acetate complex
Yun, Jaesook,Kim, Daesung,Yun, Hoseop
, p. 5181 - 5183 (2005)
A new, air stable and well-defined carbene-copper(II) complex has been prepared, which is an efficient precatalyst for the 1,2- and 1,4-reduction of carbonyl compounds under hydrosilylation conditions. The Royal Society of Chemistry 2005.
A novel Cu(II)-Mg-system for allylation and reduction of carbonyl compounds
Sarangi,Sarangi, Chintamani,Nayak,Nayak, Amalendu,Nanda,Nanda, Bhagabat,Das,Das, Nalin B.,Sharma,Sharma, Ram P.
, p. 7119 - 7122 (1995)
Allylation of a variety of carbonyl compounds with allylic halides could be induced by Cu(II)-Mg to give corresponding homoallylic alcohols with high chemoselectivity. Cu(II)-Mg/THF-H2O was found to be an efficient reduction system of aldehyde to alcohol.
Zn(BH4)2/Al2O3: A new synthetic method for the efficient and convenient reduction of organic carbonyl compounds to their corresponding alcohols
Setamdideh, Davood,Khezri, Behrooz,Rahmatollahzadeh, Mehdi
, p. 1 - 13 (2013)
Zn(BH4)2 (0.5-2 mmol) in the presence of Al 2O3 (1 mmol) reduces a variety of organic carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds to their corresponding alcohols. The reduction reactions were realized in THF at room temperature affording high to excellent yields of the products. The chemoselective reduction of aldehydes over ketones was successfully accomplished with this reducing system. In addition, regioselectivity and exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was successfully accomplished.
An iron-catalysed hydrosilylation of ketones
Nishiyama, Hisao,Furuta, Akihiro
, p. 760 - 762 (2007)
The combination of Fe(OAc)2 and multi-nitrogen-based ligands such as N,N,N′,N′-tetramethyethylenediamine, bis-tert-butyl- bipyridine, or bis(oxazolinyl)pyridine can efficiently catalyse hydrosilylation of ketones to give the corresponding alcohols in high yields including asymmetric catalysis. The Royal Society of Chemistry.
CHEMOSELECTIVE REDUCTION OF ALDEHYDES WITH TETRA-n-BUTYLAMMONIUM TRIACETOXYBOROHYDRIDE
Nutaitis, Charles F.,Gribble, Gordon W.
, p. 4287 - 4290 (1983)
Aldehydes, but not ketones, are smoothly reduced to alcohols by tetra-n-butylammonium triacetoxyborohydride in refluxing benzene.
Effect of the niobium state on the properties of NbSiBEA as bifunctional catalysts for gas- and liquid-phase tandem processes
Kyriienko, Pavlo I.,Larina, Olga V.,Popovych, Nataliia O.,Soloviev, Sergiy O.,Millot, Yannick,Dzwigaj, Stanislaw
, p. 27 - 36 (2016)
NbSiBEA zeolites contained isolated framework mononuclear Nb(V) (Nb0.7SiBEA) and a mixture of framework mononuclear and extra-framework polynuclear Nb(V) (Nb2.0SiBEA) were prepared by two-step postsynthesis method as evidenced by XRD, NMR, DR UV–vis and FTIR. DR UV–vis showed that two types of framework mononuclear Nb(V) are present in Nb0.7SiBEA, while Nb2.0SiBEA mainly contained isolated mononuclear Nb(V) in the framework of zeolite and polynuclear Nb(V) in the extra-framework position. FTIR with pyridine and 2,6-di-tert-butylpyridine as probe molecules showed that major amount Lewis and weak Br?nsted acidic sites are formed by incorporation of niobium in the framework of zeolites as mononuclear Nb(V). The catalytic properties of Nb-containing zeolites were investigated in tandem processes of ethanol conversion into 1,3-butadiene (gas-phase) and synthesis of unsymmetrical ethers from aromatic aldehyde and aliphatic alcohol (liquid-phase). It has been found that Nb0.7SiBEA catalyst, containing only isolated framework mononuclear Nb(V) is more active than Nb2.0SiBEA in the conversion of ethanol and ethanol/acetaldehyde mixture into 1,3-butadiene, MPV reduction of crotonaldehyde with ethanol and etherification of 4-methoxybenzyl alcohol with 2-butanol. The higher specific activity (turnover number/frequency) of Nb0.7SiBEA than Nb2.0SiBEA catalyst has been revealed for gas- and liquid-phase tandem processes.
Hydrogen bonding and catalysis of solvolysis of 4-methoxybenzyl fluoride
Toteva, Maria M.,Richard, John P.
, p. 9798 - 9805 (2002)
Values of ko = 8.0 × 10-3 s-1 and kH = 2.5 × 10-2 M-1 s-1, respectively, were determined for the spontaneous and the acid-catalyzed cleavage of 4-methoxybenzyl fluoride (1-F) to form the 4-methoxybenzyl carbocation (1+). Values of kF = 1.8 × 107 M-1 s-1 and kHF = 7.2 × 104 M-1 s-1 were determined for addition of F- and HF to 1+ for reaction in the microscopic reverse direction. Evidence is presented that the reversible addition of HF to 1+ to give 1-F + H+ proceeds by a concerted reaction mechanism. The relatively small 250-fold difference between the reactivities of fluoride ion and neutral HF toward 1+ is attributed to the tendency of the strong aqueous solvation of F- to decrease its nucleophilic reactivity and to the advantage for the concerted compared with the usual stepwise pathway for addition of HF. There is no significant stabilization of the transition state for cleavage of 1-F from general acid catalysis by 0.80 M cyanoacetate buffer at pH 1.7. The estimated 3 kcal/mol larger Marcus intrinsic barrier for heterolytic cleavage of 1-F than for cleavage of 1-Cl is attributed to a lag in the development at the transition state of the ca. 30 kcal/mol greater stabilizing solvation of the product ion F- compared with Cl-. The decrease in the electronegativity of X along the series X = F, OH, Cl is accompanied by a ca. 1010-fold increase in the carbon basicity compared with the proton basicity of X-.
ATP regeneration by a single polyphosphate kinase powers multigram-scale aldehyde synthesisin vitro
Tavanti, Michele,Hosford, Joseph,Lloyd, Richard C.,Brown, Murray J. B.
, p. 828 - 837 (2021)
ATP recycling systems are required to avoid the addition of stoichiometric quantities of cofactor and facilitate industrial implementation of ATP-dependent enzymes. One factor that limits the biocatalytic application of these enzymes is the lack of a scalable AMP to ATP regeneration system. Whole-cells or a combination of purified enzymes are often exploited for ATP regeneration from AMP, whereas cell free systems comprising a single crude enzyme preparation would be preferred. To establish such a system, we focussed on polyphosphate kinases (PPKs) to find a single enzyme that could be used to power ATP-consuming reactions. Screening of some previously reported PPKs revealed limitations of these biocatalysts for scale-up purposes. As such, a panel of novel putative PPK2-III enzymes was constructed and compared to characterised enzymes belonging to the same class. Multidimensional small-scale screening revealed that PPK12 (from an unclassifiedErysipelotrichaceaebacterium) displays enhanced expression levels, ATP formation rates, polyphosphate tolerance and stability under a variety of harsh conditions. The carboxylic acid reductase (CAR) catalysed reduction of carboxylates to aldehydes was chosen as a model reaction to test the applicability of PPK12 as a bifunctional biocatalyst for ATP regeneration from AMP. The implementation of the identified ATP-recycling enzyme provided the first example of cell free multigram-scale aldehyde synthesis employing enzymes and a single PPK2-III, paving the way for affordable scalable ATP regeneration technologies.
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Shankland,Gomberg
, p. 4973,4975 (1930)
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Chemoselective tetrahydropyranylation of alcohols and their detetrahydropyranylation using silicasulphuric acid as a reusable catalyst
Pore,Desai, Uday V.,Mane,Wadgaonkar
, p. 2135 - 2142 (2004)
A simple, mild, and efficient protocol for chemoselective protection of alcohols over phenols as tetrahydropyranyl ethers and their deprotection using silicasulphuric acid as a reusable solid acid catalyst is described.
A Mild Heteroatom (O -, N -, and S -) Methylation Protocol Using Trimethyl Phosphate (TMP)-Ca(OH) 2Combination
Tang, Yu,Yu, Biao
, (2022/03/27)
A mild heteroatom methylation protocol using trimethyl phosphate (TMP)-Ca(OH)2combination has been developed, which proceeds in DMF, or water, or under neat conditions, at 80 °C or at room temperature. A series of O-, N-, and S-nucleophiles, including phenols, sulfonamides, N-heterocycles, such as 9H-carbazole, indole derivatives, and 1,8-naphthalimide, and aryl/alkyl thiols, are suitable substrates for this protocol. The high efficiency, operational simplicity, scalability, cost-efficiency, and environmentally friendly nature of this protocol make it an attractive alternative to the conventional base-promoted heteroatom methylation procedures.
Hydroboration Reaction and Mechanism of Carboxylic Acids using NaNH2(BH3)2, a Hydroboration Reagent with Reducing Capability between NaBH4and LiAlH4
Wang, Jin,Ju, Ming-Yue,Wang, Xinghua,Ma, Yan-Na,Wei, Donghui,Chen, Xuenian
, p. 5305 - 5316 (2021/04/12)
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.
A mild and selective Cu(II) salts-catalyzed reduction of nitro, azo, azoxy, N-aryl hydroxylamine, nitroso, acid halide, ester, and azide compounds using hydrogen surrogacy of sodium borohydride
Kalola, Anirudhdha G.,Prasad, Pratibha,Mokariya, Jaydeep A.,Patel, Manish P.
supporting information, p. 3565 - 3589 (2021/10/12)
The first mild, in situ, single-pot, high-yielding well-screened copper (II) salt-based catalyst system utilizing the hydrogen surrogacy of sodium borohydride for selective hydrogenation of a broad range of nitro substrates into the corresponding amine under habitancy of water or methanol like green solvents have been described. Moreover, this catalytic system can also activate various functional groups for hydride reduction within prompted time, with low catalyst-loading, without any requirement of high pressure or molecular hydrogen supply. Notably, this system explores a great potential to substitute expensive traditional hydrogenation methodologies and thus offers a greener and simple hydrogenative strategy in the field of organic synthesis.
