cas 5240-32-4, 1-ETHYNYL CYCLOHEXANYL ACETATE

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Enhancing the Catalytic Activity of 4-(Dialkylamino)pyridines by Conformational Fixation
Six times more active than DMAP (1), the tricyclic DMAP analogue 2 catalyzes the acetylation of a tertiary alcohol with acetic anhydride. The experimental results can be rationalized by quantum chemical calculations.
Heinrich, Markus R.,Klisa, Heike Sabine,Mayr, Herbert,Steglich, Wolfgang,Zipse, Hendrik
p. 4826 - 4828
(2003)
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Development of a triazinedione-based dehydrative condensing reagent containing 4-(dimethylamino)pyridine as an acyl transfer catalyst
A new triazinedione-based reagent, (N,N′-dialkyl)triazinedione-4-(dimethylamino)pyridine (ATD-DMAP) was developed for the operationally simple dehydrative condensation of carboxylic acids. This reagent comprises an ATD core and DMAP as the leaving group, which is liberated into the reaction system to accelerate acyl transfer reactions. Upon adding ATD-DMAP to a mixture of carboxylic acids and alcohols in the presence of an amine base, the corresponding esters were formed rapidly at room temperature. Moreover, dehydrative condensation between carboxylic acids and amines using ATD-DMAP proceeded in high yield.
Liu, Jie,Fujita, Hikaru,Kitamura, Masanori,Shimada, Daichi,Kunishima, Munetaka
supporting information
p. 4712 - 4719
(2021/06/11)

Regioselective Synthesis of Multifunctional Allylic Amines; Access to Ambiphilic Aziridine Scaffolds
We describe, for the first time, a highly regioselective hydrosilylation of propargylic amines. The reaction utilizes a PtCl2/XantPhos catalyst system to deliver hydrosilanes across the alkyne to afford multifunctional allylic amines in high yields. The reaction is tolerant to a wide variety of functional groups and provides high value intermediates with two distinct functional handles. The synthetic applicability of the reaction has been shown through the synthesis of diverse ambiphilic aziridines.
McLaughlin, Mark G.,Roberts, Dean D.
supporting information
p. 4463 - 4467
(2021/06/28)

Enhancing catalytic activity of pyridines: Via para -iminophosphorano substituents
Four pyridines decorated with π-donating iminophosphorano substituents (R3PN-) in the 4-position were assessed as acylation catalysts. These catalysts display high sensitivity to the groups at phosphorus, with activities that are well correlated to the corresponding Hammett-type substituent constants (σp+), and can achieve superior activity over the most active dialkylamino-substituted pyridines. Iminophosphorano-substituted pyridines represent an easily accessible, tunable, and highly active class of nucleophilic organocatalysts. This journal is
Charlton, Grant D.,Dyker, C. Adam,Richard, Nicholas A.
p. 9167 - 9171
(2021/11/13)

Synthesis and evaluation of 1,1,7,7-tetramethyl-9-azajulolidine (TMAJ) as a highly active derivative of N,N-dimethylaminopyridine
1,1,7,7-Tetramethyl-9-azajulolidine (TMAJ), which theoretical studies have suggested as a highly active DMAP analog, was synthesized for the first time. The catalytic activity of TMAJ was confirmed by the acetylation reactions of various tert-alcohols. TMAJ showed much higher catalytic activity than DMAP and one of the highest activity levels among the conventional DMAP analogs. These experimental results were in good agreement with the previous theoretical studies.
Tsutsumi, Tomohiro,Saitoh, Arisa,Kasai, Tomoyo,Chu, MengYue,Karanjit, Sangita,Nakayama, Atsushi,Namba, Kosuke
supporting information

(2020/05/28)

Synthesis of 1,2-Dihydro-Substituted Aniline Analogues Involving N -Phenyl-3-aza-Cope Rearrangement Using a Metal-Free Catalytic Approach
An efficient metal-free domino reaction leading to structural/electronically divergent 1,2-dihydropyridines from easily accessible propargyl vinyl anilines via N-phenyl 3-aza-Cope sigmatropic rearrangement is reported with good to excellent yields using 1,2-dichlorobenzene as solvent under thermal conditions. Spirocyclic substitution is also tolerated under the present optimized conditions.
Alduhaish, Osamah,Varala, Ravi,Adil, Syed Farooq,Khan, Mujeeb,Siddiqui, Mohammed Rafiq H.,Alwarthan, Abdulrhman,Alam, M. Mujahid
(2020/10/02)

Neighboring Carbonyl Group Assisted Oxyacetoxylation of Propargylic Carboxylates with Retention of Chirality under Metal Free Condition
A metal-free oxyacetoxylation method of primary, secondary and tertiary propargylic carboxylates with retention of chirality was presented. The reaction proceeds through the intramolecular nucleophilic attack of the neighboring carbonyl group on an alkynyliodonium intermediate. The process is general with broad substrate scope and is amenable for application to a variety of propargyl carboxylates including those obtained from natural products. Insight into the mechanistic pathway by isotopic labelling (using H2O18 and D2O) and controlled experiments confirmed. (Figure presented.).
Pradhan, Tapas R.,Mohapatra, Debendra K.
p. 3605 - 3611
(2019/07/04)

Synthesis of Multisubstituted Allenes, Furans, and Pyrroles via Tandem Palladium-Catalyzed Substitution and Cycloisomerization
A palladium-catalyzed propargyl substitution reaction of propargyl acetates with indium organothiolates is developed for the synthesis of multisubstituted allenyl sulfides. This procedure can be applied to the synthesis of multisubstituted furans and pyrroles via tandem palladium-catalyzed propargyl substitution and cycloisomerization reaction in one pot.
Ryu, Taekyu,Eom, Dahan,Shin, Seohyun,Son, Jeong-Yu,Lee, Phil Ho
supporting information
p. 452 - 455
(2017/02/10)

Convenient synthesis of allenylphosphoryl compounds: Via Cu-catalysed couplings of P(O)H compounds with propargyl acetates
A novel Cu-catalysed substitution reaction of propargyl acetates with P(O)H compounds is developed to afford allenylphosphoryl compounds via C-P bond coupling in high yields under mild conditions. A plausible mechanism involving the nucleophilic interception of the Cu-allenylidene intermediates is proposed.
Shen, Ruwei,Luo, Bing,Yang, Jianlin,Zhang, Lixiong,Han, Li-Biao
supporting information
p. 6451 - 6454
(2016/05/24)

Palladium-Catalyzed [2+1] Cycloadditions Affording Vinylidenecyclopropanes as Precursors of 7-Membered Carbocycles
Palladium(II) acetate in association with secondary phosphine oxides provides an efficient catalytic system for [2+1] cycloadditions starting from oxanorbornene derivatives and tertiary propargyl esters giving rise to vinylidenecyclopropanes. This reaction is specific to bidentate phosphinito-phosphinous acid ligands generated from secondary phosphine oxides. The [2+1] cycloaddition was found broad in scope with a high tolerance to various functional groups. Moreover, vinylidenecyclopropanes were straightforwardly converted into oxabicyclo[3.2.1]oct-2-ene derivatives through a palladium-catalyzed ring-expansion. Finally, the oxa bridge cleavage of oxatricyclic compounds yields functionalized 7-membered carbocycles.
Lepronier, Aymeric,Achard, Thierry,Giordano, Laurent,Tenaglia, Alphonse,Buono, Gerard,Clavier, Herve
supporting information
p. 631 - 642
(2016/02/27)

Graphite oxide-catalyzed acetylation of alcohols and phenols
Graphite oxide (GO) was used as a catalyst for the reactions of alcohols and phenols with acetic anhydride. The acetates of primary and secondary alcohols were prepared in good to excellent yields in short reaction time under mild conditions. Electron deficient phenols could be converted to the corresponding acetates steadily. As an efficient catalyst, GO is easily available, cheap, moderately toxic and weakly acidic.
Liu, Yuan-Yuan,Qi, Jun-Mei,Bai, Li-Sha,Xu, Yue-Long,Ma, Ning,Sun, Fei-Fei
supporting information
p. 726 - 730
(2016/05/19)

Examination of Pyridazine as a Possible Scaffold for Nucleophilic Catalysis
Pyridazines with amino groups positioned para to each aromatic ring nitrogen and fixed in six-membered rings were prepared. The representative symmetric amino N-Et derivative was found to slightly exceed DMAP in catalytic activity in the acetylation reaction of a tertiary alcohol in C6D6. Nucleophilicity eclipsing that of DMAP was established in competitive reactions using phenacyl bromide as the electrophile, and the unsymmetric N-Et derivative was revealed to have even higher nucleophilicity.
Tamaki, Airi,Kojima, Satoshi,Yamamoto, Yohsuke
p. 8710 - 8721
(2016/10/14)

Borylation of propargylic substrates by bimetallic catalysis. Synthesis of allenyl, propargylic, and butadienyl bpin derivatives
Bimetallic Pd/Cu and Pd/Ag catalytic systems were used for borylation of propargylic alcohol derivatives. The substrate scope includes even terminal alkynes. The reactions proceed stererospecifically with formal S N2′ pathways to give allenyl boronates. Opening of propargyl epoxides leads to 1,2-diborylated butadienes probably via en allenylboronate intermediate.
Zhao, Tony S. N.,Yang, Yuzhu,Lessing, Timo,Szabó, Kálmán J.
supporting information
p. 7563 - 7566
(2014/06/10)

Annelated pyridines as highly nucleophilic and Lewis basic catalysts for acylation reactions
New heterocyclic derivatives of 9-azajulolidine have been synthesized and characterized with respect to their nucleophilicity and Lewis basicity. The Lewis basicity of these bases as quantified through their theoretically calculated methyl-cation affinities correlate well with the experimentally measured reaction rates for addition to benzhydryl cations. All newly synthesized pyridines show exceptional catalytic activities in benchmark acylation reactions, which correlate only poorly with Lewis basicity or nucleophilicity parameters. A combination of Lewis basicity with charge and geometric parameters in the framework of a three-component quantitative structure-activity relationship (QSAR) model is, however, highly predictive. Copyright
Tandon, Raman,Unzner, Teresa,Nigst, Tobias A.,De Rycke, Nicolas,Mayer, Peter,Wendt, Bernd,David, Olivier R. P.,Zipse, Hendrik
supporting information
p. 6435 - 6442
(2013/07/05)

Inductive effects through Alkyl Groups - How long is long enough?
The influence of the length of alkyl substituents on various kinetic, thermodynamic, and spectroscopic properties of 4-(dialkylamino)pyridines has been determined by using a combination of experimental and theoretical methods. The chain-length dependence of these properties has subsequently been analyzed by using a quantitative model for through-bond inductive effects. Substituent effects of linear alkyl groups show a saturation effect beyond four carbon atoms for numerous properties of 4-(dialkylamino)pyridines as test substrates. These observations can be rationalized by using an increment-based method for the calculation of inductive substituent effects. Copyright
Tandon, Raman,Nigst, Tobias A.,Zipse, Hendrik
supporting information
p. 5423 - 5430
(2013/09/02)

Iron(III) tosylate catalyzed acylation of alcohols, phenols, and aldehydes
Iron(III) p-toluenesulfonate (tosylate) is an efficient catalyst for acetylation of alcohols, phenols, and aldehydes. The acetylation of 1° and 2° alcohols, diols, and phenols proceeded smoothly with 2.0 mol % of catalyst. However, the reaction worked well with only a few 3° alcohols. The methodology was also applicable to the synthesis of a few benzoate esters but required the use of 5.0 mol % catalyst. Aldehydes could also be converted into the corresponding 1,1-diesters (acylals) under the reaction conditions. Iron(III) tosylate is an inexpensive, and easy to handle, commercially available catalyst.
Baldwin, Neil J.,Nord, Anna N.,O'Donnell, Brendan D.,Mohan, Ram S.
p. 6946 - 6949
(2013/01/15)

Gold-catalyzed regioselective hydration of propargyl acetates assisted by a neighboring carbonyl group: Access to α-acyloxy methyl ketones and synthesis of (±)-actinopolymorphol B
A general atom-economical approach for the synthesis of α-acyloxy methyl ketone is demonstrated through regioselective hydration of a wide range of propargyl acetates. Readily available catalyst comprising of 1% Ph 3PAuCl and 1% AgSbF6 in dioxane-H2O efficiently hydrolyzes the terminal alkynes of the propargyl acetate in the absence of acid promoters at ambient temperature within a short time. Effective regioselective hydration is facilitated by the neighboring carbonyl group as demonstrated through 18O-labeling study. Compatibility of functional moieties and tolerance to various acid-labile protecting groups are observed. The catalytic condition is also suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-acyloxy methyl ketone is transformed to 1,2-diol and 1,2-amino alcohol derivatives. Synthesis of actinopolymorphol B is achieved for the first time involving hydration of the propargyl acetate as the key step.
Ghosh, Nayan,Nayak, Sanatan,Sahoo, Akhila K.
supporting information; experimental part
p. 500 - 511
(2011/04/17)

Immobilized DMAP derivatives rivaling homogeneous DMAP
The copper-catalyzed Huisgen reaction between azides and alkynes was utilized to covalently attach derivatives of 4-(dimethylamino)pyridine (DMAP) to a polystyrene resin (PS) support. The catalytic potential of these constructs as determined in acylation and aza-Morita-Baylis-Hillman reactions far exceeds that of commercially available DMAP-PS resins and is fully competitive with DMAP in homogeneous solution. Immobilization of 3,4-diaminopyridine catalysts on polystyrene by using the copper-catalyzed Huisgen reaction allowed the preparation of new supported catalysts ofunprecedented catalytic activity in acylation and aza-Morita-Baylis-Hillman reactions. Copyright
D'Elia, Valerio,Liu, Yinghao,Zipse, Hendrik
supporting information; experimental part
p. 1527 - 1533
(2011/04/22)

Cyclization-carbonylation-cyclization coupling reactions of propargyl acetates and amides with palladium(II)-bisoxazoline catalysts
Clever boxing: A cyclization-carbonylation-cyclization-coupling reaction of propargyl acetates 1 or amides 2 in the presence of a palladium(II)- bisoxazoline (box) catalyst afforded symmetrical ketones of types 3 and 4, respectively, containing two heterocyclic groups in moderate to excellent yields (see scheme; tfa=trifluoroacetate). Compounds 3 were converted into ketones containing two 3(2H)-furanone rings.
Yasuhara, Sumie,Sasa, Makiko,Kusakabe, Taichi,Takayama, Hiroyuki,Kimura, Masayuki,Mochida, Tomoyuki,Kato, Keisuke
supporting information; experimental part
p. 3912 - 3915
(2011/06/20)

Counterattack mode differential acetylative deprotection of phenylmethyl ethers: Applications to solid phase organic reactions
A counterattack protocol for differential acetylative cleavage of phenylmethyl ether has been developed. The phenylmethyl moiety is liberated as benzyl bromide that is isolated and reused providing advantages in terms of waste minimization/utilization and atom economy. The applicability of this methodology has been extended for solid phase organic reactions with the feasibility of reuse of the solid support.
Chakraborti, Asit K.,Chankeshwara, Sunay V.
supporting information; experimental part
p. 1367 - 1370
(2009/07/04)

Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, and thiols in room temperature Ionic liquids
Ruthenium(III) chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature) in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]). The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.
Xi, Zhiwen,Hao, Wenyan,Wang, Pingping,Cai, Mingzhong
experimental part
p. 3528 - 3537
(2009/12/24)

The catalytic potential of 4-guanidinylpyridines in acylation reactions
A series of 3-alkyl-4-guanidinylpyridines with variable alkylation pattern have been synthesized and characterized with respect to their catalytic potential in acylation reactions of alcohols. The ability of the substitution pattern to stabilize acylpyridinium cations, which act as critical intermediates in the catalytic cycle of pyridine-catalyzed acylation reactions, has been assessed at the MP2(FC)/6-31+G(2d,p)//B98/6-31G(d) level of theory and inclusion of solvent effects in chloroform using the PCM continuum solvation model. The most active 4-guanidinylpyridines are among those having the most electron-rich pyridine ring. The influence of the type and concentration of the auxiliary base on the catalytic activity has also been studied. While the change from triethylamine to N,N-diisopropylethylamine as the auxiliary base does not lead to a systematic increase or decrease in the catalytic rates, the complete absence of auxiliary base leads to a 27-fold reduction in reaction rate. Georg Thieme Verlag Stuttgart.
Held, Ingmar,Larionov, Evgeny,Bozler, Christian,Wagner, Felicia,Zipse, Hendrik
scheme or table
p. 2267 - 2277
(2009/12/31)

3,4-diaminopyridine derivatives
3,4-Diaminopyridine derivatives corresponding to a specified formula are produced by (a) reacting 3,4-diaminopyridine with a 1,2-dicarbonyl compound to form a diimine; (b) reducing the diimine to a diamine; and (c) replacing at least a hydrogen atom on nitrogen at position 4 of the pyridine ring. These compounds are useful as catalysts.
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(2008/12/07)

THIAZOLYL-DIHYDRO-QUINAZOLINE
Disclosed are thiazolyl-dihydro-quinazolines of general formula (I) wherein the groups R1 to R4 have the meanings given in the claims and specification, the isomers thereof, and processes for preparing these compounds and their use as pharmaceutical compositions.
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Page/Page column 13

(2008/06/13)

Photoacylation of alcohols in neutral medium
We report here conditions which allow the photoacylation of primary, secondary and tertiary alcohols with N-acetyl-5,7-dinitroindoline under exceptionally mild conditions, at wavelengths harmless to most functional groups, including otherwise photosensitive ones. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Debieux, Jean-Luc,Cosandey, Anne,Helgen, Celine,Bochet, Christian G.
p. 2073 - 2077
(2008/02/04)

An unprecedented Pd-catalyzed, water-promoted sequential oxidative aminocarbonylation-cyclocarbonylation process leading to 2-oxazolidinones
An unprecedented, Pdl2-catalyzed, sequential oxidative aminocarbonylation-cyclocarbonylation process, leading to 2-oxazolidinone derivatives 3 in good to excellent yields starting from readily available α,α-disubstituted 2-ynylamines 1 and secondary amines 2, is reported. In the case of an α-monosubstituted substrate, the initially formed 2-oxazolidinone derivative underwent shift of the double bond to give a 3H-oxazol-2-one derivative in excellent isolated yield.
Gabriele, Bartolo,Plastina, Pierluigi,Salerno, Giuseppe,Mancuso, Raffaella,Costa, Mirco
p. 3319 - 3322
(2008/02/12)

Modular design of pyridine-based acyl-transfer catalysts
Derivatives of 3,4-diaminopyridine have been synthesized and studied as catalysts for acyl-transfer reactions. The design of these catalysts is guided by the stability of their acetyl intermediates as determined through theoretical calculations at the B3LYP/6-311 + G(d,p)//B3LYP/6-31G(d) level of theory. The most promising catalysts have been synthesized through a three- to five-step synthesis starting from 3,4-diaminopyridine. The catalytic activity has been determined for the acylation of 1-ethynylcyclohexanol with acetic anhydride at 23°C and with isobutyric anhydride at 40°C. For both reactions, the catalytic activity depends dramatically on the substitution pattern of the diaminopyridines. Best results are obtained with catalysts containing alkyl substituents at both amine nitrogens. Georg Thieme Verlag Stuttgart.
Held, Ingmar,Xu, Shangjie,Zipse, Hendrik
p. 1185 - 1196
(2008/02/02)

Development of more potent 4-dimethylaminopyridine analogues
The syntheses of bicyclic diaminopyridines 3 and 4 and tricyclic triaminopyridines 5 and 6, two novel series of nucleophilic catalysts, are described. Arguments are made for predicting the superiority of these catalysts over DMAP and even 2, the best esterification catalyst reported to date. The efficiencies of DMAP, PPY, and 2-6 in catalyzing the esterification of tertiary alcohols were compared. As predicted, 5 and 6 were about 6-fold more effective than DMAP and slightly better than 2.
Singh, Satwinder,Das, Goutam,Singh, Om V.,Han, Hyunsoo
p. 401 - 404
(2008/02/12)

A highly selective, high-speed, and hydrolysis-free O-acylation in subcritical water in the absence of a catalyst
(Chemical Equation Presented) Fast and furious: A wide range of alcohols are acylated by acetic anhydride, in the absence of catalyst, in subcritical water in a flow-type microreaction system. The esters are selectively produced in high yields at temperatures of 200 to 250°C. Varying the amount of acetic anhydride added with respect to the alcohols allows the regioselective acylation of one or both hydroxy groups of various dihydroxy compounds (see picture).
Sato, Masahiro,Matsushima, Keiichiro,Kawanami, Hajime,Ikuhsima, Yutaka
p. 6284 - 6288
(2008/04/05)

Synthesis of N-propargylanabasine derivatives by the mannich reaction
N-Propargylanabasine derivatives bearing various substituents at the carbon atom of the alkyne fragment were obtained by the reaction of anabasine hydrochloride with terminal alkynes and paraformaldehyde. The reaction proceeded with retention of the C(2) chiral center in anabasine fragment. The by-products of the reaction, including 1,3-diacetylene (the products of dimerization of alkynes) and conjugated vinylacetylenes (the rearrangement products of the Mannich adducts) were isolated and characterized.
Mavrov,Zlotin
p. 1637 - 1647
(2008/09/18)

Magnesium bistrifluoromethanesulfonimide as a new and efficient acylation catalyst
Magnesium bistrifluoromethanesulfonimide catalyzed the acetylation of phenols, alcohols, and thiols under solvent-free conditions at room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic anhydrides (e.g., chloroacetic and benzoic anhydrides) required higher temperature (～80 °C). Chemoselective acetylation, pivalation, and benzoylation took place with acid-sensitive alcohols without any competitive dehydration/rearrangement.
Chakraborti, Asit K.,Shivani
p. 5785 - 5788
(2007/10/03)

Dialkylaminopyridine-functionalized mesoporous silica nanosphere as an efficient and highly stable heterogeneous nucleophilic catalyst
A new nucleophilic catalytic system comprised of dialkylaminopyridine- functionalized mesoporous silica nanosphere (DMAP-MSN) has been synthesized and characterized. We have demonstrated that this material is an efficient heterogeneous catalyst for Baylis-Hillman, acylation, and silylation reactions with good reactivity, product selectivity, and recyclability. We envision that this DMAP-functionalized mesoporous silica material can also serve as an effective heterogeneous catalyst for many other catalytic nucleophilic reactions.
Chen, Hung-Ting,Huh, Seong,Wiench, Jerzy W.,Pruski, Marek,Lin, Victor S.-Y.
p. 13305 - 13311
(2007/10/03)

N-ARYL-SUBSTITUTED CYCLIC AMINE DERIVATIVE AND MEDICINE CONTAINING THE SAME AS ACTIVE INGREDIENT
The present invention provides an excellent squalene synthase inhibitor. Specifically, it provides a compound (I) represented by the following formula, a salt thereof or a hydrate of them. Wherein R1 represents an optionally substituted vinyl group or an aromatic ring which may be substituted; ???n is an integer of 0 to 2; ???X, Y and Z are the same as or different from each other and each represents an optionally substituted carbon atom, or an optionally substituted nitrogen a tom, sulfuratomoroxygenatom, and Y optionally represents a single bond, and when Y represents the single bond, the ring to which X, Y and Z belong is a 5-membered ring; ???CyA represents a 5- to 14 membered non-aromatic cyclic amino groupornon-aromatic cyclic amidogroupwhichmaybe substituted, and the non-aromatic cyclic amino group or the non-aromatic cyclic amido group optionally having an oxygen atom or a sulfur atom; ???W represents a chain expressed by(1) optionally substituted -CH2-CH2-,(2) optionally substituted -CH=CH-,(3) -C≡C-,(4) an optionally substituted phenylene group,(5) a single bond,(6) -NH-CO-,(7) -CO-NH-,(8) -NH-CH2-,(9) -CH2-NH-,(10) -CH2-CO-,(11) -CO-CH2-,(12) -O-(CH2)m-,(13) -(CH2)m-O- (where m represents an integer of 0 to 5),(14) -O-CH2-CR2=,(15) -O-CH2-CHR2- (where R2 represents a hydrogen atom, a C1-6 alkyl group or a halogen atom),(16) -NH-S(O)1-,(17) -S(O)1-NH-,(18) CH2-S(O)1-, or(19) -S(O)2-CH2- (where 1 represents 0, 1, or 2); and ???A represents a group having any of the following structural formulae: (wherein R3 and R4 represent independently a hydrogen atom or an optionally substituted C1-6 alkyl group, or combine through a carbon chain optionally containing a heteroatom to form a ring; ???R5 and R6 represent independently a hydrogen atom or an optionally substituted C1-6 alkyl group, or combine through a carbon chain optionally containing a heteroatom to form a ring; ???R7 represents a hydrogen atom, an optionally substituted C1-6 alkyl group, a hydroxyl group, an alkoxy group, a halogen atom or an optionally substituted amino group; ???R8 represents a hydrogen atom, a hydroxyl group, an alkoxy group, a halogen atom or an optionally substituted amino group; ???B1 represents an optionally substituted carbon atom, or an optionallysubstitutednitrogenatom, oxygen atom or sulfur atom; ???B2 represents an optionally substituted carbon atom or nitrogen atom; ???a and b represent an integer of 0 to 4, provided that a+b is an integer of 0 to 4; ???c represents 0 or 1; and----- represents a single bond or a double bond, provided that when c is 1 in which A is a quinuclidine having R8 represented by the case where R8 is a hydrogen atom or a hydroxyl group; Arl is an aromatic heterocycle; and W is one of (1) to (3), (6) to (11) and (16) to (19) are excluded).
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(2010/02/05)

Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, thiols, and amines
Ruthenium(III) chloride catalyzes the acylation of a variety of phenols, alcohols, thiols, and amines under mild conditions. Some of the major advantages of this method are high yields, short reaction times, ease of operation, and compatibility with other protecting groups.
Kanta De, Surya
p. 2919 - 2922
(2007/10/03)

Copper(II) Tetrafluoroborate-Catalyzed Acetylation of Phenols, Thiols, Alcohols, and Amines
Copper(II) tetrafluoroborate efficiently catalyzes acetylation of structurally diverse phenols, alcohols, thiols, and amines with stoichiometric amounts of Ac2O under solvent-free conditions at room temperature. Acid-sensitive alcohols are smoothly acetylated without competitive side reactions. The reaction is influenced by the steric and electronic factors associated with the substrate as well as the anhydride. Acetylation of a sterically hindered substrate requires excess of anhydride and longer time. Acylation with less electrophilic anhydrides affords poor to moderate yields.
Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
p. 111 - 115
(2007/10/03)

Zirconiuni(IV) chloride as a new, highly efficient, and reusable catalyst for acetylation of phenols, thiols, amines, and alcohols under solvent-free conditions
Zirconium(IV) chloride has been found to be a new, highly efficient, and reusable catalyst for acetylation of structurally diverse phenols, thiols, amines, and alcohols under solvent-free condtions. Acetylation of sterically hindered and electron deficient phenols is achieved in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acid-sensitive alcohols undergo acetylation with excellent chemoselectivity without competitive side reactions such as dehydration or rearrangement. The mild Lewis acid property of the catalyst enables the acetylation to be carried out with optically active substrates without any detrimental effect on the optical purity.
Chakraborti, Asit K.,Gulhane, Rajesh
p. 627 - 630
(2007/10/03)

Perchloric acid adsorbed on silica gel as a new, highly efficient, and versatile catalyst for acetylation of phenols, thiols, alcohols, and amines
Perchloric acid adsorbed on silica gel efficiently catalyses acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions.
Chakraborti, Asit K.,Gulhane, Rajesh
p. 1896 - 1897
(2007/10/03)

Indium(III) chloride as a new, highly efficient, and versatile catalyst for acylation of phenols, thiols, alcohols, and amines
Indium(III) chloride efficiently catalyses the acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid sensitive alcohols are smoothly acylated without competitive side reactions. Acylation of 2-hydroxynaphthalene is carried out with carboxylic acids adopting the mixed anhydride protocol using trifluoroacetic anhydride.
Chakraborti, Asit K.,Gulhane, Rajesh
p. 6749 - 6753
(2007/10/03)

Electrostatic catalysis by ionic aggregates: Scope and limitations of Mg(ClO4)2 as acylation catalyst
Alkali and alkaline earth metal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4) 2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric amounts of anhydride at room temperature under solvent free conditions in the presence of catalytic amount of Mg(ClO4) 2. Sterically hindered and electron deficient phenols are efficiently acylated. Acylation with sterically hindered anhydrides such as iso-butyric, pivalic, and benzoic anhydrides are carried out with phenols and alcohols in excellent yields. Acid-sensitive alcohols are acylated in excellent yields without any competitive side reactions.
Chakraborti, Asit K.,Sharma, Lalima,Gulhane, Rajesh,Shivani
p. 7661 - 7668
(2007/10/03)

Fluoroboric acid adsorbed on silica gel as a new and efficient catalyst for acylation of phenols, thiols, alcohols, and amines
Fluoroboric acid supported on silica gel efficiently catalyzes acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid-sensitive alcohols are smoothly acylated without competitive side reactions.
Chakraborti, Asit K.,Gulhane, Rajesh
p. 3521 - 3525
(2007/10/03)

Bismuth Oxide Perchlorate as a Highly Efficient Catalyst for Heteroatom Acylation under Solvent-Free Conditions
Bismuth oxide perchlorate efficiently catalyzes the acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Sterically hindered and electron deficient phenols are acetylated in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acylation of acid-sensitive alcohols is carried out efficiently without competitive side reactions. Optically active substrates are acetylated without any detrimental effect on the optical purity.
Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
p. 1805 - 1808
(2007/10/03)

Lithium perchlorate catalyzed acetylation of alcohols under mild reaction conditions
Lithium perchlorate is found to efficiently catalyze the acetylation of alcohols and phenols with acetic anhydride in good to excellent yields.
Nakae,Kusaki,Sato
p. 1584 - 1586
(2007/10/03)

Highly powerful and practical acylation of alcohols with acid anhydride catalyzed by Bi(OTf)3
Bi(OTf)3-catalyzed acylation of alcohols with acid anhydride was evaluated in comparison with other acylation methods. The Bi(OTf)3/acid anhydride protocol was so powerful that sterically demanding or tertiary alcohols could be acylated smoothly. Less reactive acylation reagents such as benzoic and pivalic anhydride are also activated by this catalysis. In these cases, a new technology was developed in order to overcome difficulty in separation of the acylated product from the remaining acylating reagent: methanolysis of the unreacted anhydride into easily separable methyl ester realized quite easy separation of the desired acylation product. The Bi(OTf)3/acid anhydride protocol was applicable to a wide spectrum of alcohols bearing various functionalities. Acid-labile THP- or TBS-protected alcohol, furfuryl alcohol, and geraniol could be acylated as well as base-labile alcohols. Even acylation of functionalized tertiary alcohols was effected at room temperature.
Orita,Tanahashi,Kakuda,Otera
p. 8926 - 8934
(2007/10/03)

Highly efficient and versatile acylation of alcohols with Bi(OTf)3 as catalyst
A very convenient route for the acylation of alcohols is provide by using a Bi(OTf)3 catalyst [Eq. (1)]. In this protocol hindered and functionalized alcohols are acylated at 25°C, and solvents can be employed without purification. R= primary, secondary, tertiary alkyl, aryl; R'=Me, Ph, tBu.
Orita, Akihiro,Tanahashi, Chiaki,Kakuda, Atsushi,Otera, Junzo
p. 2877 - 2879
(2007/10/03)

An Efficient Acylation of Tertiary Alcohols with Isopropenyl Acetate Mediated by an Oxime Ester and Cp*2Sm(thf)2
An efficient method for the acylation of tertiary alcohols with isopropenyl acetate (1) by the use of an oxime and Cp*2Sm(thf)2 as catalyst was developed. Thus, various types of tertiary alcohols could be acylated with 1 in the presence of a catalytic amount of cyclohexanone oxime acetate (2) and Cp*2Sm(thf)2 under mild conditions to form the corresponding acetates in excellent yields. Acid-sensitive terpene alcohols such as linalool were successfully acetylated by the present method to give acetyl linalool in quantitative yield. This method enables an alternative acylation of tertiary alcohols under acid-free conditions.
Tashiro, Daisuke,Kawasaki, Yumi,Sakaguchi, Satoshi,Ishii, Yasutaka
p. 8141 - 8144
(2007/10/03)

Scandium trifluoromethanesulfonate as an extremely active Lewis acid catalyst in acylation of alcohols with acid anhydrides and mixed anhydrides
Scandium trifluoromethanesulfonate (triflate), which is commercially available, is a practical and useful Lewis acid catalyst for acylation of alcohols with acid anhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acid anhydrides of not only primary alcohols but also sterically-hindered secondary or tertiary alcohols. The method presented is especially effective for selective macrolactonization of ω-hydroxy carboxylic acids.
Ishihara, Kazuaki,Kubota, Manabu,Kurihara, Hideki,Yamamoto, Hisashi
p. 4560 - 4567
(2007/10/03)

Scandium Trifluoromethanesulfonate as an Extremely Active Acylation Catalyst
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Ishihara, Kazuaki,Kubota, Manabu,Kurihara, Hideki,Yamamoto, Hisashi
p. 4413 - 4414
(2007/10/02)

Tributylphosphine: A Remarkable Acylation Catalyst
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Vedejs, E.,Diver, S. T.
p. 3358 - 3359
(2007/10/02)

Unsaturated spiro-γ-lactone formation by the dissociative reduction of bromoacetates
Unsaturated spiro-γ-butyrolactones can be prepared in good yields from bromoacetate precursors by a simple route that requires only 2-propanol as solvent and free radical initiation.
Kolt,Griller,Wayner
p. 7539 - 7540
(2007/10/02)

A New Acylation Catalyst
Cobalt(II) chloride catalyses the acylation of alcohols and amines with anhydrides in excellent yields.
Ahmad, Saeed,Iqbal, Javed
p. 114 - 115
(2007/10/02)