- A novel sublimable organic salt: Synthesis, characterization, thermal behavior, and catalytic activity for the synthesis of arylidene, heteroarylidene, and alkylidene malonates
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A novel sublimable organic salt was synthesized, and its chemical structure was characterized by FTIR, 1D NMR, 2D NMR, and elemental analysis. In addition, the thermal phase transitions and thermal stability of new organic salt were investigated. The DSC and TGA results showed that the organic salt could convert into constituent molecules at dec. ~ 200?°C) under atmospheric pressure without forming the liquid phase. Then, it was recondensed to regenerate the initial organic salt in the cool part of the vial. Therefore, it can be a promising organic salt towards the regeneration of spent catalyst from synthesis processes when the reaction mixture contains poorly volatile components and includes its use in gas-phase procedures. Also, the catalytic efficiency of new organic salt was investigated in the Knoevenagel condensation reaction. A variety of substituted arylidene and alkylidene malonates were isolated in 78–95% yield within six hours.? Under the optimized reaction conditions, the current catalytic procedure exhibited superiority compared to the mixed piperazine/acetic acid, piperidine/acetic acid, and piperidinium acetate. There were no significant changes in the new organic salt chemical structure and catalytic activity even after the 5th run. This work revealed the importance of the existence of simultaneous hydrogen bond acceptor/donor groups in our environmentally friendly catalyst to promote the Knoevenagel condensation reaction without the use of metal-containing catalysts.
- Johari, Suzaimi,Zaharani, Lia,Gorjian, Hayedeh,Johan, Mohd R.,Khaligh, Nader G.
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p. 361 - 377
(2021/09/18)
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- Solid-phase synthesis of arylidene and alkylidene malonates, as versatile intermediates, catalyzed using mesoporous poly-melamine–formaldehyde as a nitrogen-rich porous organic polymer (POP)
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An efficient solid/slurry-state synthesis of arylidene and alkylidene malonates as versatile intermediates is developed in the presence of mesoporous poly-melamine–formaldehyde. The condensation reaction was conducted through a ball milling process as a non-conventional procedure and a greener methodology at room temperature under solvent-free conditions. The mesoporous heterogeneous catalyst could be recovered and reused ten times, and the results showed a negligible loss of catalytic activity. Various aryl- and heteroarylidene malonates, as well as dimethyl (cyclohexylidene)malonate, were isolated in good to high yields under optimal conditions. The use of hazardous reagents and solvents were minimized in the current method, and separation of catalyst and products, as well as the recovery and reusing of catalyst, were performed by cost-effective procedures. This work revealed that the synergistic effect of numerous Lewis base sites together with acceptor-donner hydrogen bonding functional groups in porous organic polymer (POP), and its high porosity plays a vital role to promote the carbon–carbon coupling reaction in the solid phase synthesis.
- Khaligh, Nader Ghaffari,Gorjian, Hayedeh,Fahim, Hoda,Titinchi, Salam J. J.
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p. 3529 - 3536
(2021/05/11)
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- An Expeditious Route to trans-Configured Tetrahydrothiophenes Enabled by Fe(OTf)3-Catalyzed [3+2] Cycloaddition of Donor–Acceptor Cyclopropanes with Thionoesters
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A synthetic route to trans-configured tetrahydrothiophenes (THTs) through Fe(OTf)3-promoted [3+2] cycloaddition of donor–acceptor cyclopropanes with thionoesters was developed. The cycloaddition proceeded in high yield with high diastereoselectivity, affording transient α-alkoxy THTs. Not only aromatic and aliphatic thionoesters, but also thionolactone were applicable to the present iron catalysis. Further transformation of the S,O-ketal functionality of the product was achieved in a highly trans diastereoselective manner. Moreover, the utility of our methodology was clearly demonstrated by the synthesis of enantioenriched trans-configured THTs.
- Matsumoto, Yohei,Nakatake, Daiki,Yazaki, Ryo,Ohshima, Takashi
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supporting information
p. 6062 - 6066
(2018/03/28)
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- Phosphine-Mediated Dimerization of Conjugated Ene-Yne Ketones: Stereoselective Construction of Dihydrobenzofurans
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A new strategy for the phosphine-mediated dimerization of conjugated ene-yne ketones to produce functionalized dihydrobenzofurans has been developed, affording diversified 4,5-dihydrobenzofurans in moderate to excellent yields with high diastereoselectivities under mild conditions. This new synthetic method can tolerate a variety of functional groups and can be performed on a gram scale and in an asymmetric variant using the chiral phosphine Xyl-BINAP to give the desired products with up to 94% ee. (Figure presented.).
- Zhu, Cheng-Zhi,Sun, Yao-Liang,Wei, Yin,Shi, Min
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supporting information
p. 1263 - 1270
(2017/04/18)
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- Indium(III)-catalyzed knoevenagel condensation of aldehydes and activated methylenes using acetic anhydride as a promoter
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The combination of a catalytic amount of InCl3 and acetic anhydride remarkably promotes the Knoevenagel condensation of a variety of aldehydes and activated methylene compounds. This catalytic system accommodates aromatic aldehydes containing a variety of electron-donating and -withdrawing groups, heteroaromatic aldehydes, conjugate aldehydes, and aliphatic aldehydes. Central to successfully driving the condensation series is the formation of a geminal diacetate intermediate, which was generated in situ from an aldehyde and an acid anhydride with the assistance of an indium catalyst.
- Ogiwara, Yohei,Takahashi, Keita,Kitazawa, Takefumi,Sakai, Norio
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p. 3101 - 3110
(2015/03/30)
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- Tetrahydro-1,3-oxazepines via Intramolecular Amination of Cyclopropylmethyl Cation
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An efficient synthesis of tetrahydro-1,3-oxazepines was developed involving the regioselective intramolecular amination of cyclopropylmethyl cation. The cation was generated by the abstraction of one imidate group in bis-imidate bearing a carbocation-stabilizing substituent. Using 1,1,2,3-tetrasubstituted cyclopropane substrates, highly diastereoselective intramolecular amination to trans-tetrahydro-1,3-oxazepines was achieved. The resulting tetrahydro-1,3-oxazepines were transformed to the homoallylamine derivatives in high yields.
- Skvorcova, Marija,Grigorjeva, Liene,Jirgensons, Aigars
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supporting information
p. 2902 - 2904
(2015/06/30)
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- Unexpected regioselectivity switch: Organophosphine-triggered reactions of cyclopropene-1,1-dicarboxylates with aldehydes
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With tris(4-methoxyphenyl)phosphine as the nucleophilic reagent, the readily available cyclopropene-1,1-dicarboxylates undergo a ring-opening reaction to generate a Wittig-type intermediate, which would react with aromatic aldehydes to yield (E)-5-aryl-2-(methoxycarbonyl)-2,4-pentadienoates. It is interesting to observe that the regioselectivity of the ring-opening reaction is switched.
- Ni, Shengjun,Chen, Jie,Ma, Shengming
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supporting information
p. 3290 - 3293
(2013/07/26)
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- Asymmetric michael addition of ketones to alkylidene malonates and allylidene malonates via enamine - Metal lewis acid bifunctional catalysis
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Novel enamine-metal Lewis acid bifunctional catalysts were successfully applied to the asymmetric Michael addition of ketones to alkylidene malonates, offering excellent stereoselectivity (up to >99% ee and >99:1 dr). The asymmetric Michael addition of ketones to allylidene malonates was also achieved.
- Liu, Lu,Sarkisian, Ryan,Xu, Zhenghu,Wang, Hong
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supporting information
p. 7693 - 7699
(2012/11/07)
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- Comparative study of 1,5-dinitrogen schiff bases as potential ligands in palladium-catalyzed allylic alkylation
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1-(2′-Pyrido and 2′-quinolino)-(1R)-arylethylamino) -ethylidenes (7-12) were prepared as potential ligands in PdII catalytic complexes for enantioselective allylic alkylation of 1,3-diphenyl-1-acetoxy-propene-2 (15). Alkylation with palladium complexes of 7-12 yielded 1,3-diphenyl-1-dimethylmalonyl-propene-2 (14) with enantioselectivity up to 55 % e.e. Enantioselectivity is discussed in view of the results recently reported for structurally related 1,5-bidentate dinitrogen ligands of C1 symmetry. Reversal of enantioselectivity observed for the ligands 10 and 11 is attributed to the inversion of steric requirements in the second coordination sphere of their catalytic complexes.
- Sepac, Dragan,Roje, Marin,Hamersak, Zdenko,Sunjic, Vitomir
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p. 235 - 239
(2007/10/03)
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- Macrocyclic vs acyclic derivatives of chiral bis(oxazolines); ligand distortion and enantioselectivity of Pd(II) complexes in catalytic allylic alkylation
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Pd(II) complexes of acyclic (1,2;4,5) and macrocyclic (3,6-10) derivatives of 1,5-bis(oxazolines), are tested in the enantioselective allylic alkylation of racemic 1,3-diphenyl-3-acetoxyprop-2-ene (14) by dimethylmalonate anion to allyl malonate derivativ
- ?epac, Dragan,Marini?, ?eljko,Portada, Tomislav,?ini?, Mladen,?unji?, Vitomir
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p. 1159 - 1167
(2007/10/03)
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- Palladium-catalyzed isobenzofuran generation under neutral conditions via oxidative addition to lactol methyl ether
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(matrix presented) A novel method for generation of isobenzofuran is developed from lactol methyl ether using palladium catalysts. This reaction can be carried out under neutral conditions and hence improves on the precedent methods under acidic or basic conditions and at high temperatures. Furthermore, this Pd-catalyzed isobenzofuran generation suggests the involvement of oxidative addition of Pd catalyst into benzylic or allylic methyl ethers.
- Mikami, Koichi,Ohmura, Hirofumi
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p. 3355 - 3357
(2007/10/03)
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- Synthesis of polysubstituted 1,3-cyclohexadicnes from β-branched α,β-alkenals and monoesters of ylidenemalonic acids
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3-Methyl- and 3-phenyl-2-butenal react with monoesters of alkylidene-, alkenylidene-, and arylmethylenemalonic acids in the presence of piperidine as the catalyst to give esters of 4,6-disubstituted 1,3-cyclohexadienecarboxylic acids in 23-96 % yields. Under the same conditions cyclohexylideneacetic aldehyde reacts with the monoesters of prenylidene- and benzylidenemalonic acid to afford mixtures of 1,8a-trans- and 1,8a-cis-isomers of 1-substituted alkyl 1,5,6,7,8,8a-hexahydronaphthalene-2-carboxylates, the ratios and configurations of which were determined by means of 1H NMR spectroscopy. In some cases the formation of cyclic dienes is impeded by the competing process of decarboxylation of acidic ylidenemalonates. The derivatives of 4,6-diphenyl-1,3-cyclohexadienecarboxylic acid were shown to be convenient precursors for the preparation of meta-terphenyls.
- Nigmatov,Kornilova,Serebryakov
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p. 144 - 152
(2007/10/03)
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- Reactions of diazocompounds with carbonyl compounds mediated by diorganyl telluride and catalytic amount of CuI compounds: Conversion of aldehydes to a
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A one-pot reaction of diorganyl telluride, diazo-compounds including dimethyl diazomalonate and ethyl diazoacetate, carbonyl compound and catalytic amount of Cu(I)I afforded the olefination products in high yields. The reaction is proposed to be through diorganyltelluronium bis (methoxycarbonyl)methylide and (ethoxycarbonyl)methylide respectively.
- Zhou, Zhang-Lin,Huang, Yao-Zeng,Shi, Li-Lan
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p. 6821 - 6830
(2007/10/02)
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- Tellurium-Assisted Cycloprpanation and Alkylidenation of α,β-Unsaturated Carbonyl Compounds with Dibromomalonic Esters
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Dibutyl telluride assists cyclopropanation of α,β-unsaturated ketone, ester, and nitrile with dibromomalonic esters without solvent at room temperature.In addition, it effects alkylidenation of aldehydes including α,β-unsaturated aldehyde with the same reagent.
- Matsuki, Toshiaki,Hu, Nan Xing,Otsubo, Tetsuo,Ogura, Fumio
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p. 2105 - 2107
(2007/10/02)
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- ALLYLIC GEMINAL DIACETATES. UNUSUAL CARBONYL SUBSTITUTES VIA METAL CATALYZED REACTIONS
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Palladium catalysis facilitates replacement of an acetoxy group of an allylic geminal diacetate by stabilized nucleophiles.
- Trost, Barry M.,Vercauteren, Joseph
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p. 131 - 134
(2007/10/02)
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