- Synthesis and 1,3-dipolar cycloaddition reactions of new pyrazolo[1,5,4-ef][1,5]benzodiazepines
-
New pyrazolo[1,5,4-ef][1,5]benzodiazepines have been synthesized by condensation of 7-aminoindazole with β-keto esters, alkylation and 1,3-dipolar cycloaddition. The peri- and regioselective cycloaddition of allylpyrazolo-1,5-benzodiazepinones and 2,4,6-t
- Bouissane, Latifa,El Kazzouli, Said,Rakib, El Mostapha,Khouili, Mostafa,Hannioui, Abdellah,Benchidmi, Mohammed,Essassi, El Mokhtar,Guillaumet, Ge?rald
-
-
Read Online
- Asymmetric Allylation of 2-Oxocycloalkanecarboxylates
-
In this study, the highly enantioselective α-allylation of α-substituted β-ketoesters, particularly 2-oxocycloalkanecarboxylates, is achieved by synergistic catalysis with an achiral palladium complex and a chiral primary amino acid. Various α-allylated β-ketoesters containing a quaternary carbon stereogenic center are synthesized in high yields (up to 97%) with excellent enantioselectivity (up to 99% ee).
- Yoshida, Masanori,Yano, Shohei,Hara, Shoji
-
-
Read Online
- Synthesis and biochemical evaluation of warhead-decorated psoralens as (Immuno)proteasome inhibitors
-
The immunoproteasome is a multicatalytic protease that is predominantly expressed in cells of hematopoietic origin. Its elevated expression has been associated with autoimmune diseases, various types of cancer, and inflammatory diseases. Selective inhibit
- ?terman, Andrej,Gobec, Martina,Gobec, Stanislav,Mravljak, Janez,Proj, Matic,Rejc, Luka,Schiffrer, Eva Shannon,Sosi?, Izidor
-
-
- Accumulation of Active Species in Silica Mesopore: Effect of the Pore Size and Free Base Additives on Pd-catalyzed Allylation using Allylic Alcohol
-
A mesoporous silica-supported Pd complex was prepared using various types of porous silica supports (pore size: 16–31 ?). The effects of the pore size and base additive properties on the catalytic allylation were investigated. The activity of the Pd-catal
- Chun, Wang-Jae,Kawashima, Sae,Manaka, Yuichi,Motokura, Ken,Nambo, Masayuki
-
-
- Electrochemical oxidative cyclization of olefinic carbonyls with diselenides
-
The tandem cyclization of olefinic carbonyls with easily accessible diselenides facilitated by electrochemical oxidation has been successfully developed, which provides an environmentally friendly method for the construction of C-Se and C-O bonds simultaneously. A series of seleno dihydrofurans and seleno oxazolines, bearing fragile heterocycles, subtle C-I bonds and supernumerary vinyl groups, were forged using this elegant chelation strategy. Neither metal catalysts nor external chemical oxidants are required to promote this transformation.
- Guan, Zhipeng,Wang, Yunkun,Wang, Huamin,Huang, Yange,Wang, Siyuan,Tang, Hongding,Zhang, Heng,Lei, Aiwen
-
supporting information
p. 4976 - 4980
(2019/09/30)
-
- A distinctive transformation based diversity oriented synthesis of small ring carbocycles and heterocycles from biocatalytically derived enantiopure α-substituted-β-hydroxyesters
-
A series of structurally novel small ring carbocyclic and heterocyclic molecules were accessed in an enantiopure fashion. The starting materials, α-substituted-β-hydroxyesters, were achieved through the biocatalytic dynamic kinetic resolution of parent β-
- Halder, Joydev,Das, Debabrata,Nanda, Samik
-
p. 2549 - 2575
(2018/04/12)
-
- Ni-Catalyzed Regioselective Dicarbofunctionalization of Unactivated Olefins by Tandem Cyclization/Cross-Coupling and Application to the Concise Synthesis of Lignan Natural Products
-
We disclose a (terpy)NiBr2-catalyzed reaction protocol that regioselectively difunctionalizes unactivated olefins with tethered alkyl halides and arylzinc reagents. The reaction shows an excellent functional group tolerance (such as ketones, es
- Kc, Shekhar,Basnet, Prakash,Thapa, Surendra,Shrestha, Bijay,Giri, Ramesh
-
p. 2920 - 2936
(2018/03/09)
-
- Silica Support-Enhanced Pd-Catalyzed Allylation Using Allylic Alcohols
-
Although allylation using allylic alcohol is an environmentally-friendly method because of water being the sole byproduct in such reactions, allylic alcohol is one of the most difficult allylating agents in Pd-catalyzed allylation of nucleophiles. In this study, we successfully developed a mesoporous silica-supported Pd complex as an efficient catalyst for the allylation of nucleophiles using allylic alcohols as allylating agents. The allylic alcohol is activated by the silanol group on the support surface, which easily undergoes a π-allylpalladium intermediate formation. The catalytic activity of the supported Pd complex was ca. 9 times higher than that of its homogeneous precursor Pd complex. A highest turnover number of 4500 based on Pd was achieved. Various nucleophiles and allylic alcohol derivatives could be used as substrates. Not only the detailed catalyst structure but also the reaction mechanism including the concerted activation of allylic alcohol by the Pd complex and silanol were investigated by several spectroscopic techniques, such as Pd K-edge XAFS, solid-state NMR, and in-situ FT-IR measurements.
- Motokura, Ken,Ikeda, Marika,Kim, Minjune,Nakajima, Kiyotaka,Kawashima, Sae,Nambo, Masayuki,Chun, Wang-Jae,Tanaka, Shinji
-
p. 4536 - 4544
(2018/09/21)
-
- MMZNiY-Catalyzed Tsuji–Trost Type of Reaction: A Selective Mono/Bis Allylation of Dicarbonyl Compounds
-
Abstract: An alternative method to Pd-catalyzed Tsuji–Trost reaction is developed and it provides a simpler route for the selective synthesis of a broad range of mono-/bis-allylated and cinnamylated 1,3-dicarbonyl compounds using MMZNiY catalyst at room temperature. Product selectivity can be controlled by the proper choice of catalyst. The catalyst was also well characterized by SEM, TEM, HRTEM, EDAX and X-ray analysis. Other advantages of catalyst like its ease of preparation, functional tolerance and its reusability are also highlighted.
- Senthilkumar, Samuthirarajan,Thangapriya, Cheirmakani,Alagumurugayee, Raman,Kumarraja, Mayilvasagam
-
p. 2755 - 2763
(2017/09/14)
-
- Concerted Catalysis in Tight Spaces: Palladium-Catalyzed Allylation Reactions Accelerated by Accumulated Active Sites in Mesoporous Silica
-
The surface of mesoporous silica was modified with a Pd–bisphosphine complex and/or a tertiary amine group for concerted acceleration of allylation reactions. Mesoporous-silica-supported catalysts with a 1.6 nm pore diameter showed higher performance than nonporous or larger mesoporous silica-supported catalysts owing to the accumulation of active sites into a confined space. For the case in which allyl alcohol was used in the reaction, the presence of a silanol group on the surface was quite effective: the turnover number of Pd was nine times greater than that of the homogeneous Pd complex.
- Motokura, Ken,Ikeda, Marika,Nambo, Masayuki,Chun, Wang-Jae,Nakajima, Kiyotaka,Tanaka, Shinji
-
p. 2924 - 2929
(2017/08/15)
-
- Tunable Aerobic Oxidative Hydroxylation/Dehydrogenative Homocoupling of Pyrazol-5-ones under Transition-Metal-Free Conditions
-
A practical and tunable transition-metal-free aerobic oxidation of pyrazol-5-ones preparing either 4-hydroxypyrazoles (via C-H hydroxylation) or bispyrazoles (via dehydrogenative homocoupling) is described. The K2CO3/dioxane reagent system predominately promoted hydroxylation to deliver the α-hydroxylated pyrazoles. In contrast, the formation of bispyrazoles was overwhelmingly preferred with CH3CN as the reaction medium without any additives.
- Sheng, Xuguang,Zhang, Jinlong,Yang, Huameng,Jiang, Gaoxi
-
supporting information
p. 2618 - 2621
(2017/05/24)
-
- Highly efficient Tsuji-Trost allylation in water catalyzed by Pd-nanoparticles
-
Palladium nanoparticles stabilized by poly(vinylpyrrolidone) catalyze Tsuji-Trost allylations in water with very high turnover numbers. The di-allylation of methylene active compounds and the allylation of bio-based phenols was performed in high yield. The allylation of lignin showed a high selectivity towards the phenolic OH groups.
- Llevot,Monney,Sehlinger,Behrens,Meier
-
supporting information
p. 5175 - 5178
(2017/07/12)
-
- Co-immobilization of a palladium-bisphosphine complex and strong organic base on a silica surface for heterogeneous synergistic catalysis
-
Co-immobilization of a palladium-bisphosphine complex and a strong organic base, 1,4-diazabicyclo[2.2.2]octane (DABCO), on a silica support was successfully achieved. The new catalyst structure was characterized by X-ray photoelectron spectroscopy, solid-
- Motokura, Ken,Saitoh, Koki,Noda, Hiroto,Uemura, Yohei,Chun, Wang-Jae,Miyaji, Akimitsu,Yamaguchi, Sho,Baba, Toshihide
-
p. 331 - 335
(2016/02/05)
-
- A Pd-bisphosphine complex and organic functionalities immobilized on the same SiO2 surface: Detailed characterization and its use as an efficient catalyst for allylation
-
A Pd-bisphosphine complex and several organic functionalities were immobilized on the same SiO2 surface. The samples thus prepared were characterized by solid-state NMR, XPS, and XAFS. Based on the curve-fitting analysis of Pd K-edge EXAFS spectra, both the local environment of the immobilized Pd complexes and the interactions with the co-immobilized organic functions were discussed. The SiO2-supported Pd-bisphosphine complex and DABCO exhibited excellent catalytic performance for the allylation of various nucleophiles: a TON of up to 106000 was obtained. Both the catalyst activation pathway and the reaction mechanism were also discussed on the basis of the structure of the used catalyst samples.
- Motokura, Ken,Saitoh, Koki,Noda, Hiroto,Chun, Wang-Jae,Miyaji, Akimitsu,Yamaguchi, Sho,Baba, Toshihide
-
p. 5380 - 5388
(2016/07/21)
-
- Enantioselective biocatalytic reduction of 2,2-disubstituted ethylacetoacetates: An indirect desymmetrization approach for the synthesis of enantiopure (S)-4-hydroxy-3,3-disubstituted pentane-2-ones
-
Ethyl 2,2-disubstituted-3-oxobutanoates were biocatalytically reduced to the corresponding (S)-ethyl 3-hydroxy-2,2-disubstitutedbutanoate with the growing cells of Klebsiella pneumoniae (NBRC 3319) with excellent enantioselection. The biocatalytically derived enantiopure hydroxyl esters were then synthetically manipulated to give (S)-4-hydroxy-3,3-disubstituted pentane-2-ones. The whole process can be regarded as an indirect enantioselective enzymatic desymmetrization method for the synthesis of (S)-4-hydroxy-3,3-disubstituted pentane-2-ones.
- Halder, Joydev,Das, Debabrata,Nanda, Samik
-
p. 1197 - 1208
(2015/10/28)
-
- Three-step synthetic pathway to fused bicyclic hydantoins involving a selenocyclization step
-
Sequential 5-alkenyl hydantoin and pyrrolidine ring-forming reactions have been applied in the synthesis of conformationally constrained fused bicyclic scaffold. They are assembled by a three-step reaction sequence from two variable building blocks (readily available β-ketoesters and alkenyl halides) by combining a Bucherer-Bergs reaction with a final selenium-promoted intramolecular cyclization as a key step. The chemoselectivity of this bicyclic hydantoin formation is strongly influenced by experimental factors such as the solvent and the use of additives. The reaction is regiospecific giving only five-membered fused bicyclic hydantoins in good to excellent yields stemming from the nucleophilic attack of the nitrogen atom to a cyclic seleniranium ion intermediate during the cyclization step. A separable diastereomeric mixture is obtained; the products with bridgehead substituents and phenylseleno groups in cis relationships were formed predominantly. The reaction tolerates a variety of substitution at the double bond, furthermore, the presence of substituents at C(5) and N(3) position opens up the capability of generating a broad structural diversity.
- ?mit, Biljana M.,Pavlovi?, Radoslav Z.
-
p. 1101 - 1108
(2015/01/30)
-
- Combining palladium complex and organic amine on graphene oxide for promoted Tsuji-Trost allylation
-
In this study, we develop a facile strategy to combine an organic amine with a palladium complex on graphene oxide (GO) as a cooperative catalyst for Tsuji-Trost allylation. A tertiary amine and palladium-diamine complex are simultaneously immobilized on
- Zhao, Qingshan,Zhu, Yuanzhi,Sun, Zhen,Li, Yang,Zhang, Guoliang,Zhang, Fengbao,Fan, Xiaobin
-
p. 2609 - 2616
(2015/02/19)
-
- Highly selective palladium-benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions
-
The Pd-benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji-Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand is also proposed.
- Monopoli, Antonio,Cotugno, Pietro,Zambonin, Carlo G.,Ciminale, Francesco,Nacci, Angelo
-
supporting information
p. 994 - 999
(2015/08/19)
-
- A general synthetic approach to para-cyclophanes via ring-closing metathesis
-
A new methodology for the synthesis para-cyclophanes and longithorone C frameworks has been demonstrated via alkylation, ceric ammonium nitrate (CAN) oxidation and ring-closing metathesis as key steps.
- Kotha, Sambasivarao,Shirbhate, Mukesh E.
-
p. 1483 - 1494
(2016/02/26)
-
- A general synthetic approach to para-cyclophanes via ring-closing metathesis
-
A new methodology for the synthesis para-cyclophanes, and longithorone C frameworks has been demonstrated via alkylation, eerie ammonium nitrate (CAN) oxidation and ring-closing metathesis as key steps.
- Kotha, Sambasivarao,Shirbhate, Mukesh E.
-
p. 1483 - 1494
(2016/09/09)
-
- Palladium nanoparticles bonded to two-dimensional iron oxide graphene nanosheets: A synergistic and highly reusable catalyst for the Tsuji-Trost reaction in water and air
-
Low cost, high activity and selectivity, convenient separation, and increased reusability are the main requirements for noble-metal-nanocatalyst- catalyzed reactions. Despite tremendous efforts, developing noble-metal nanocatalysts to meet the above requirements remains a significant challenge. Here we present a general strategy for the preparation of strongly coupled Fe3O4 and palladium nanoparticles (PdNPs) to graphene sheets by employing polyethyleneimine as the coupling linker. Transmission electron microscopic images show that Pd and Fe3O4 nanoparticles are highly dispersed on the graphene surface, and the mean particle size of Pd is around 3 nm. This nanocatalyst exhibits synergistic catalysis by Pd nanoparticles supported on reduced graphene oxide (rGO) and a tertiary amine of polyethyleneimine (Pd/Fe3O4/PEI/rGO) for the Tsuji-Trost reaction in water and air. For example, the reaction of ethyl acetoacetate with allyl ethyl carbonate afforded the allylated product in more than 99% isolated yield, and the turnover frequency reached 2200 h-1. The yield of allylated products was 66% for Pd/rGO without polyethyleneimine. The catalyst could be readily recycled by a magnet and reused more than 30 times without appreciable loss of activity. In addition, only about 7.5% of Pd species leached off after 20 cycles, thus rendering this catalyst safer for the environment. Picking up speed: A multifunctional Pd nanocatalyst was synthesized by in situ growth of palladium nanoparticles (PdNPs) and the assembly of Fe3O4 NPs on reduced graphene oxide (rGO) by employing polyethyleneimine as the coupling linker. This nanocatalyst exhibits synergistic catalysis by the amine on the same rGO surface as the PdNPs for acceleration of the Tsuji-Trost reaction in water and air (see figure).
- Liu, Jian,Huo, Xing,Li, Tianrong,Yang, Zhengyin,Xi, Pinxian,Wang, Zhiyi,Wang, Baodui
-
p. 11549 - 11555
(2014/11/07)
-
- The Cu(OTf)2 catalysed microwave assisted synthesis of a new scaffold, 7-aryl-7,8-dihydropyrido[4,3-c]pyridazin-5(6H )-one
-
The synthesis of novel 7-aryl-7,8-dihydropyrido[4,3-c]pyridazin-5(6 H)-ones is described including a one-step Mannich-type reaction followed by intramolecular ring closure of ethyl 3-methylpyridazine-4-carboxylate and aldimines, catalysed by the Lewis aci
- Muylaert, Koen,Mangelinckx, Sven,Jatczak, Martyna,De Coen, Laurens M.,Van Hecke, Kristof,Stevens, Christian V.
-
p. 139 - 155
(2015/02/19)
-
- Dual platinum and pyrrolidine catalysis in the direct alkylation of allylic alcohols: Selective synthesis of monoallylation products
-
A dual platinum- and pyrrolidine-catalyzed direct allylic alkylation of allylic alcohols with various active methylene compounds to produce products with high monoallylation selectivity was developed. The use of pyrrolidine and acetic acid was essential, not only for preventing undesirable side reactions, but also for obtaining high monoallylation selectivity. Two cats are better than one: The combined use of platinum and pyrrolidine catalysts enabled the direct alkylation of allylic alcohols with reactive methylene compounds. Pyrrolidine was essential for obtaining high selectivity of the monoallylation products, which were produced without the use of excess nucleophiles. cod=1,5- cyclooctadiene, EWG=electron-withdrawing group.
- Shibuya, Ryozo,Lin, Lu,Nakahara, Yasuhito,Mashima, Kazushi,Ohshima, Takashi
-
supporting information
p. 4377 - 4381
(2014/05/06)
-
- Efficient synthesis of highly substituted pyrroles through a Pd(OCOCF 3)2-catalyzed cascade reaction of 2-alkenal-1,3-dicarbonyl compounds with primary amines
-
We describe an unprecedented Pd(OCOCF3)2-catalyzed cascade process for the synthesis of highly functionalized 1,2,3,5- tetrasubstituted pyrroles with high efficiency. Unlike documented methods relying on preformed enamines and active halogenated terminal alkenes, the process employs simple 2-alkenal-dicarbonyls and primary amines in 'one-pot'. The Royal Society of Chemistry 2013.
- Yang, Wei,Huang, Liliang,Liu, Hong,Wang, Wei,Li, Hao
-
p. 4667 - 4669
(2013/06/05)
-
- First iodine-catalyzed deallylation of reactive allyl methylene esters
-
C-Allyl cleavage has been developed using the inexpensive and mild reagent iodine in dimethylsulfoxide. A variety of compounds with active methylene groups were C-deallylated using this reagent. This method is efficient and operationally simple in comparison to the methods using transition-metal complexes. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Nawghare, Beena R.,Lokhande, Pradeep D.
-
p. 1955 - 1963
(2013/06/05)
-
- Bifunctional mesoporous silica nanoparticles as cooperative catalysts for the Tsuji-Trost reaction-tuning the reactivity of silica nanoparticles
-
Bifunctional mesoporous silica nanoparticles (MSNs) bearing Pd-complexes and additional basic sites were prepared and tested as cooperative active catalysts in the Tsuji-Trost allylation of ethyl acetoacetate. Functionalization of the MSNs was realized by postmodification using click-chemistry. The selectivity of mono versus double allylation was achieved by control of reaction temperature and the nature of the catalyst.
- Dickschat, Arne T.,Behrends, Frederik,Surmiak, Sabrina,Wei?, Mark,Eckert, Hellmut,Studer, Armido
-
supporting information
p. 2195 - 2197
(2013/03/29)
-
- Efficient allylation of nucleophiles catalyzed by a bifunctional heterogeneous palladium complex-tertiary amine system
-
We demonstrate the synergistic catalysis of a silica-supported diaminopalladium complex and a tertiary amine (SiO2/diamine/Pd/ NEt2) as well as synthetic scope of the Tsuji-Trost reaction of 1,3-dicarbonyls, phenols, and carboxylic acids with allyl carbonate and acetates. The synergistic catalysis of SiO2/diamine/Pd/NEt 2 exhibited wide applicability and high activity for the Tsuji-Trost reaction. For example, the reaction of ethyl 3-oxobutanate with allyl methyl carbonate afforded the allylated product in >99% yield at 70 °C for 5 h. The yield of allylated products was 26% for SiO2/diamine/Pd, without immobilization of the tertiary amine group. In the reaction of 1.0 mmol of ethyl 3-oxobutanate using 0.60 μmol of Pd in SiO2/diamine/Pd/NEt 2, the turnover number (TON) of Pd reached up to 1070 within 24 h. Phenols with electron-withdrawing groups, such as nitro and chloro groups, on the para position resulted in high product yields. The SiO2/diamine/ Pd/NEt2 catalyst was reusable at least 4 times without appreciable loss of its activity and selectivity in the reaction of p-chlorophenol. Copyright
- Noda, Hiroto,Motokura, Ken,Miyaji, Akimitsu,Baba, Toshihide
-
p. 973 - 980
(2013/05/08)
-
- Tsuji-Trost allylation of CH acids in supercritical carbon dioxide: Advantages and problems
-
The Pd(PPh3)4-catalyzed reaction between α-cyano or β-oxo carboxylates and allyl acetate in supercritical carbon dioxide with the K2CO3-18-crown-6 system as a base affords exhaustive allylation products in high yields, whereas malononitrile and acetylacetone of higher CH acidity form the mixtures of mono- and diallylated derivatives in moderate yields.
- Vasil'ev, Andrei A.,Kuchurov, Ilya V.,Zlotin, Sergei G.
-
-
- Heterogeneous synergistic catalysis by a palladium complex and an amine on a silica surface for acceleration of the Tsuji-Trost reaction
-
The cooperative surface-catalysis strategy of a Bronsted acid and an organic base can be extended to a metal complex and organic base pair. A silica-supported diaminopalladium complex and a tertiary amine were prepared and characterized. The Pd-catalyzed
- Noda, Hiroto,Motokura, Ken,Miyaji, Akimitsu,Baba, Toshihide
-
supporting information; experimental part
p. 8017 - 8020
(2012/09/07)
-
- Diversity-oriented approach to macrocyclic cyclophane derivatives via ring-closing metathesis
-
A short synthetic approach to the macrocyclic framework of longithorone C is described via ring-closing metathesis using the Grubbs 2nd generation catalyst. Georg Thieme Verlag Stuttgart ? New York.
- Kotha, Sambasivarao,Shirbhate, Mukesh E.
-
p. 2183 - 2188
(2012/11/07)
-
- Dynamic kinetic resolution of α-substituted β-ketoesters catalyzed by Baeyer-Villiger monooxygenases: Access to enantiopure α-hydroxy esters
-
BVMOs make a play: The dynamic kinetic resolution of racemic α-alkyl-β-ketoesters was performed through a selective Baeyer-Villiger oxidation employing different Baeyer-Villiger monooxygenases (BVMOs) in mild basic media. The product diesters were obtained with excellent yields and enantioselectivities, and used as precursors for optically active α-hydroxy esters.
- Rioz-Martínez, Ana,Cuetos, Aníbal,Rodríguez, Cristina,De Gonzalo, Gonzalo,Lavandera, Iván,Fraaije, Marco W.,Gotor, Vicente
-
supporting information; experimental part
p. 8387 - 8390
(2011/10/09)
-
- A stereoselective cyclisation cascade mediated by SmI2-H 2O: Synthetic studies towards stolonidiol
-
A cascade reaction involving sequential conjugate reduction, stereoselective aldol cyclisation and chemoselective lactone reduction mediated by SmI2-H2O provides access to a cyclopentanol bearing two vicinal quaternary stereocentres with good stereocontrol. The functionalised cyclopentanol product has been converted to a key intermediate in ongoing asymmetric studies towards stolonidiol.
- Baker, Thomas M.,Sloan, Lisa A.,Choudhury, Lokman H.,Murai, Masahito,Procter, David J.
-
experimental part
p. 1246 - 1261
(2010/11/02)
-
- Simple and efficient access to 3-ethoxycarbonylpyrroles, naphthofurans
-
An efficient method was developed for the synthesis of pyrrole and furan derivatives from enamines, phenols, and naphthols. The key steps involve iodocyclization and alumina-induced dehydroiodination reactions. Georg Thieme Verlag Stuttgart.
- Pancote, Camila G.,De Carvalho, Bruno S.,Luchez, Cibele V.,Fernandes, Joao P.S.,Politi, Mario J.,Brandt, Carlos A.
-
experimental part
p. 3963 - 3966
(2010/03/26)
-
- New Ugi-Smiles-metathesis strategy toward the synthesis of pyrimido azepines
-
(Chemical Equation Presented) A new strategy involving Ugi-Smiles coupling followed by ring-closure metathesis is described herein for the preparation of pyrimidine-fused heterocyclic scaffolds. The scope of this sequence is presented in relation with the
- El Kaim, Laurent,Grimaud, Laurence,Oble, Julie
-
p. 5835 - 5838
(2008/02/09)
-
- Montmorillonite-entrapped sub-nanoordered Pd clusters as a heterogeneous catalyst for allylic substitution reactions
-
(Chemical Equation Presented) Caught making a change: Stable sub-nanoordered Pd clusters within the interlayer spaces of montmorillonite efficiently catalyze heterogeneous allylic substitution reactions in which the coordinatively unsaturated Pd atoms enable facile formation of π-allylpalladium intermediates (see scheme). The catalyst is reusable without any loss of activity or selectivity.
- Mitsudome, Takato,Nose, Kenta,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Jitsukawa, Koichiro,Kaneda, Kiyotomi
-
p. 3288 - 3290
(2008/03/11)
-
- Solvent-controlled highly selective bis-and monoallylation of active methylene compounds by allyl acetate with palladium(0) nanoparticle
-
(Chemical Equation Presented) Palladium(0) nanoparticle has been used as an efficient catalyst for the allylation of active methylene compounds. Very efficient bisallylation is achieved for a variety of active methylene compounds by allyl acetate and its derivatives in one stroke in THF solvent. The reaction in water provides monoallylated product selectively by allyl acetate only. The recovered Pd(0) nanoparticle is recycled. A probable mechanism is suggested.
- Ranu, Brindaban C.,Chattopadhyay, Kalicharan,Adak, Laksmikanta
-
p. 4595 - 4598
(2008/03/12)
-
- Stereoselective synthesis of the monomeric unit of SCH 351448
-
The monomeric unit of the macrodiolide SCH 351448 has been synthesized from three building blocks. Strategic disconnections were chosen between C21-C22 (Wittig) and C10-C11 (stereoselective aldol). The cis configuration of both 2,6-disubstituted tetrahydropyran rings was established by a stereoselective cationic reduction. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Backes, J. Rene,Koert, Ulrich
-
p. 2777 - 2785
(2007/10/03)
-
- Solvent-dependent chemoselectivities in additions of β-carbonyl imines to allyltrimethylsilane with CTAN
-
The oxidative coupling of β-carbonyl imines and allyltrimethylsilane with CTAN were investigated in CH3CN and CH2Cl 2. In CH3CN allylation products were obtained predominantly, while in CH2Cl2, dihydropyrrole products were obtained exclusively. Solvent-assisted nucleophilic cleavage of the intermediate β-silyl cation is proposed to play a role in the solvent-dependent chemoselectivity.
- Zhang, Yang,Raines, Andrew J.,Flowers II, Robert A.
-
p. 6267 - 6272
(2007/10/03)
-
- Water enables direct use of allyl alcohol for Tsuji-Trost reaction without activators
-
(Chemical Equation Presented) An aqueous biphasic reaction system enables the direct use of allyl alcohol in the Tsuji-Trost reaction without the help of any activating reagents for allyl alcohol. The reaction conditions are neutral to basic, allowing the use of amines as the nucleophile. Theoretical calculations have elucidated the importance of hydration of the hydroxy group for the smooth generation of π-allylpalladium species.
- Kinoshita, Hidenori,Shinokubo, Hiroshi,Oshima, Koichiro
-
p. 4085 - 4088
(2007/10/03)
-
- Solvent-dependent chemoselectivities in Ce(IV)-mediated oxidative coupling reactions
-
(Matrix presented) The oxidative coupling of 1,3-diketones, β-keto esters, and β-keto silyl enol ethers with allyl trimethylsilane in the presence of CTAN was investigated. In the case of acyclic diketones and esters, different chemoselectivities were observed in CH3CN and CH 2Cl2 leading to good yields of allylation and dihydrofuran products, respectively.
- Zhang, Yang,Raines, Andrew J.,Flowers II, Robert A.
-
p. 2363 - 2365
(2007/10/03)
-
- C- vs O-alkylation of 1,3-dicarbonyl compounds using microwave irradiation
-
The study of alkylation behaviour of 1,3-dicarbonyl compounds has been carried out with microwave radiation exposure of approximately 2 min resulting in moderate to good yields of the products.
- Nayyar, Sandeep,Trehan, Inderraj,Kaur, Jasamrit
-
p. 2342 - 2345
(2007/10/03)
-
- Cascade radical cyclisations of methylenecyclopropyl ketones - Synthesis of bicyclo-[3.2.1]-octanes
-
Samarium diiodide mediated cyclisation of methylenecyclopropyl ketones, readily prepared from β-ketoesters provides a simple route to bicyclo-[3.2.1]-octanes.
- Saint-Dizier, Alexandre C.,Kilburn, Jeremy D.
-
p. 6201 - 6203
(2007/10/03)
-
- (π-Allyl)palladium complexes bearing diphosphinidenecyclobutene ligands (DPCB): Highly active catalysts for direct conversion of allylic alcohols
-
The (π-allyl)palladium complex bearing an sp2-hybridized phosphorus ligand (DPCB-OMe: 1,2-bis(4-methoxyphenyl)-3,4-bis[(2,4,6-tri-tert-butylphenyl)phosphinidene]cyclobutene) efficiently catalyzes direct conversion of allylic alcohols in the absence of activating agents of alcohols such as Lewis acids. N-Allylation of aniline proceeds at room temperature to afford monoallylated anilines in 90-97% yields. C-Allylation of active methylene compounds is also successful at 50 °C using a catalytic amount of pyridine as a base, giving monoallylation products in 85-95% yields. The catalytic mechanism involving hydrido- and (π-allyl)palladium intermediates has been proposed on the basis of stoichiometric examinations using model compounds of presumed intermediates. Copyright
- Ozawa, Fumiyuki,Okamoto, Hideyuki,Kawagishi, Seiji,Yamamoto, Shogo,Minami, Tatsuya,Yoshifuji, Masaaki
-
p. 10968 - 10969
(2007/10/03)
-
- Synthesis of 3- and 5-alkyl-6-alkyl(aryl)tetrahydropyran-2,4-diones by the condensation of β-oxo acid esters with aldehydes and ketones
-
A method is proposed for obtaining 3- and 5-alkyl-6-alkyl(aryl)tetrahydropyran-2,4-diones based on the condensation of the dianion of alkyl(dialkyl)acetoacetic ester with aldehydes and ketones.
- Lokot',Pashkovskii,Lakhvich
-
p. 707 - 714
(2007/10/03)
-
- Selenocyclofunctionalization of β-ketoamides: Synthesis of substituted dihydrofurans
-
Selenocyclofunctionalization of α-substituted β-ketoamides obtained from the aminolysis of the ethyl acetoacetate yielded dihydrofurans in moderate to good yields.
- Stefani, Hélio A.,Costa, Iguatemi M.,De O. Silva, Diogo,Menezes, Paulo H.,Rodrigues, Alessandro
-
p. 141 - 152
(2007/10/03)
-
- Palladium-tetraphosphine complex: An efficient catalyst for allylic substitution and Suzuki cross-coupling
-
A new tetraphosphine, the cis-cis-cis-1,2,3,4-tetrakis (diphenylphosphinomethyl)cyclopentane (Tedicyp) has been synthesized and used in palladium-catalyzed reactions. This tetraphosphine in combination with [Pd(C3H5)Cl]2 affords a very efficient catalyst for coupling reactions. Turnover numbers of 980 000 for allylic amination, 9 800 000 for allylic alkylation and 97 000 000 for Suzuki cross-coupling can be obtained in the presence of this catalyst.
- Feuerstein,Laurenti,Doucet,Santelli
-
p. 2320 - 2326
(2007/10/03)
-
- A new tetratertiary phosphine ligand and its use in Pd-catalyzed allylic substitution
-
A new tetraphosphine, the cis-cis-cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) 1 has been synthesized, characterized, and used in Pd-catalyzed allylic substitutions. The Tedicyp was easily prepared in seven steps from the commercially available himic anhydride. The structure of the complex Tedicyp-borane was determined by X-ray analysis. The tetraphosphine in combination with [Pd(η3-C3H5)Cl]2 affords a very efficient catalyst for allylic substitution of several allylic acetates. Under mild conditions, very high turnover numbers and turnover frequencies have been obtained.
- Laurenti,Feuerstein,Pepe,Doucet,Santelli
-
p. 1633 - 1637
(2007/10/03)
-
- Synthesis of functional monomers based on β-diketones
-
Unsaturated β-diketones - 3-allylpentane-2,4-dione, 3-allyl-1,1,1-trifluoropentane-2,4-dione, and 2-allyl-1-phenylbutane-1,3-dione-were prepared by two independent procedures: condensation and alkylation. The compounds were characterized by elemental analysis and 1H NMR and IR spectroscopy. The copper, nickel, and cobalt complexes of these β-diketones were prepared, and their thermal behavior was examined.
- Voloshanovskii,Manaeva,Shevchenko,Mamontov
-
p. 296 - 300
(2007/10/03)
-
- Use of the Nonionic Superbase P(MeNCH2CH2)3N in the Selective Monoalkylation of Active-Methylene Compounds
-
The symmetric active-methylene compounds CH2(CO2Et)2 and CH2[C(O)Me]2 are selectively monoalkylated in the presence of 1.1 equiv of a variety of alkyl halides and 1 equiv of the nonionic Superbase P(MeNCH2CH2)2N in 85-98% yields in 30 min at room temperature. The unsymmetrical active-methylene compound EtO2CCH2C(O)Me is selectively monoalkylated under the same conditions, except for the temperature, which is 0 °C, in 59-88% yields. The observation of selective C- rather than O-alkylation is rationalized in terms of the formation of an enolate whose negatively charged oxygen is sterically protected by a nearby HP(MeNCH2CH2)2N+ counterion in a tight ion pair.
- Arumugam, Subramaniam,McLeod, Dale,Verkade, John G.
-
p. 3677 - 3679
(2007/10/03)
-
- Reaction of tetracarbonyl(π-allyl)manganese with carbon nucleophiles
-
Nucleophilic attack on tetracarbony (π-allyl)manganese takes place at the terminus of the π-system, generating allylated products in 44-95% yield after oxidation. Stabilized nucleophiles (pK(a) 12-20) give mainly bis allylation whereas nonstabilized nucleophiles (pKa 25-35) give mono allylation.
- Vaughan, William S.,Gu, Henry H.,McDaniel, Keith F.
-
p. 1885 - 1888
(2007/10/03)
-