- An enamine/HB(C6F5)2 adduct as a dormant state in frustrated lewis pair chemistry
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The enamine piperidinocyclopentene reacts with HB(C6F 5)2 by formation of the C-Lewis base/B-Lewis acid adduct 10. It shows a zwitterionic iminium ion/hydridoborate structure. However, this adduct formation is apparently reversible and may generate the "invisible" frustrated Lewis pair 11 as a reactive intermediate by hydroboration of the enamine C=C bond in an equilibrium situation at room temperature. Consequently, the FLP 11 was trapped by typical FLP reactions, namely by the reaction with dihydrogen to give the ammonium/hydridoborate 12, the acetylene deprotonation products 13 and 14, and simple borane adducts with pyridine (15) and with an isonitrile (17). The products 10 and 12-15 and the isonitrile adduct 17 were characterized by X-ray diffraction. A DFT study determined the thermodynamic features of the 10 a? 11 equilibrium and of a previously discussed reference system (18 a? 19) derived by reacting piperidinocyclohexene with HB(C6F5)2.
- Xu, Bao-Hua,Bussmann, Kathrin,Froehlich, Roland,Daniliuc, Constantin G.,Brandenburg, Jan Gerit,Grimme, Stefan,Kehr, Gerald,Erker, Gerhard
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Read Online
- 1 microwave-induced montmorillonite-mediated facile synthesis of enamines
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Montmorillonite clay-mediated simple and high yielding protocol for the synthesis of various enamines with secondary amines and ketones is developed under microwave condition. This protocol is very convenient to accesses the enamines from cyclic amines with various carbonyl compounds in high yield under mild reaction conditions with short reaction time.
- Yadav, Ram Naresh,Banik, Indrani,Srivastava, Ashok Kumar,Ramos, Katherine,Banik, Bimal Krishna
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p. 249 - 254
(2020/01/08)
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- Tf2O-Mediated Intermolecular Coupling of Secondary Amides with Enamines or Ketones: A Versatile and Direct Access to β-Enaminones
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Based on the Tf2O-mediated intermolecular reaction of secondary amides with enamines derived from ketones, a novel approach to β-enaminones has been developed. The reaction is widely functional group tolerant and highly chemoselective. In the presence of 4 ? molecular sieves, the method can be extended to the one-pot condensation of secondary amides with ketones for NH β-enaminones synthesis.
- Liu, Yong-Peng,Zhu, Cheng-Jie,Yu, Cun-Cun,Wang, Ai-E,Huang, Pei-Qiang
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supporting information
p. 7169 - 7174
(2019/11/16)
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- New nucleophilic rearrangement in the mechanism of the three-component domino cyclisation affording fluoroalkylated (pyrrolo)quinazolines
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The following mechanism steps were verified for the three-component domino cyclisation affording (pyrrolo)quinazolines from 2-(aminomethyl)aniline, a very reactive oxo compound and "usual" oxo compound. The first step was a rapid reaction of very reactive oxo compound (trifluoropyruvate or hexafluoroacetone) with benzylic amino group to form hemiaminal, but not imine; the second step was the reaction of oxo compound with aromatic amino group to form imine (Schiff base) being in equilibrium with its enamine form; the third step was an intramolecular attack of the hemiaminal carbon by the enamine carbon followed by a new nucleophilic rearrangement to form tetrahydropyrimidine cycle; the forth step was closure of the lactam ring, if ester group was available as in trifluoropyruvate.2013 Elsevier B.V. All rights reserved.
- Paleta, Old?ich,Dolensky, Bohumil,Pale?ek, Ji?í,Kví?ala, Jaroslav
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supporting information
p. 1 - 11
(2014/01/06)
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- Synthesis, structure and thermal decomposition of cycloalkanone enamine peroxides
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Reactions of cycloalkanone enamines with H2O2 gave bis(1-morpholinocyclopent-1-yl)- and bis(1-morpholinocyclohex-1-yl)-peroxides, which were studied by NMR spectroscopy and X-ray diffraction. Thermolysis of bis(1-morpholinocyclohex-1-yl)-peroxide in n-hexane resulted in two major products, viz., cyclohexanone and morpholine.
- Starostin, Evgenii K.,Khrustalev, Victor N.,Antipin, Mikhail Yu.,Lalov, Andrei V.
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body text
p. 334 - 336
(2010/01/18)
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- TETRAHYDRO-CYCLOPENTYL PYRAZOLE CANNABINOID MODULATORS
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This invention is directed to a tetrahydro-cyclopentyl pyrazole cannabinoid modulator compound of formula (I): and a method for use in treating, ameliorating or preventing a cannabinoid receptor mediated syndrome, disorder or disease.
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Page/Page column 44; 49-50
(2010/11/26)
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- Novel and convenient aldolization of methyl 3,3,3-trifluoropyruvate using enamines instead of ketones
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Piperidine enamines derived from acetone, acetophenone, cyclopentanone and cyclohexanone react easily in minutes with methyl 3,3,3-trifluoropyruvate (1) to afford products of the aldol condensation in high yields at room temperature, which is in contrast to the direct aldolization of 1 with the ketones.
- Palecek, Jiri,Paleta, Oldrich
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p. 521 - 524
(2007/10/03)
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- Clay catalyzed synthesis of imines and enamines under solvent-free conditions using microwave irradiation
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The reactions of primary and secondary amines with aldehydes and ketones, respectively, are accelerated by microwaves under solvent-free conditions in the presence of montmorillonite K 10 clay to afford a high yield synthesis of imines and enamines.
- Varma, Rajender S.,Dahiya, Rajender,Kumar, Sudhir
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p. 2039 - 2042
(2007/10/03)
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- Microwave-Assisted Facile Synthesis of Imines and Enamines using Envirocat EPZGR as a Catalyst
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In a simple microwave-assisted and environmentally benign approach, aldehydes and ketones react readily with primary and secondary amines to afford imines and enamines, respectively, under solvent-free conditions using Envirocat EPZGR as a catalyst.
- Varma, Rajender S.,Dahiya, Rajender
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p. 1245 - 1246
(2007/10/03)
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- Synthesis of Enamines from Cycloalkanones and Secondary Cyclic Amines using K-10 Montmorillonite Clay
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The synthesis of enamines from cycloalkanones and secondary cyclic amines has been carried out in 85-95percent yield in the presence of K-10 montmorrilonite clay and with azeotropic removal of the water formed in the condensation.
- Dewan, Sharwan K.,Varma, Urmila,Malik, Shiv Darshan
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- SYNTHESIS ODS PERFLUOROCHEMICALS FOR USE AS BLOOD SUBSTITUTES. PART IV. ALACTROCHEMICAL FLUORINATION OF N-CYCLOALKYL-PYRROLIDINES AND -PIPERIDINES
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Electrochemical fluorination of N-cyclopentylpyrrolidine gave the corresponding F-amine together with a ring-opened compound N-(F-pentyl)-F-pyrrolidine in the ratio of 1 to 1, in 55 percent yield.N-cyclohexylpyrrolidine, N-cyclopentylpiperidine and N-cyclohexylpiperidine were also electrochemically fluorinated in the same manner to give the corresponding F-amines, their isomers with rearranged structures, and ring-opened ones, in the ratio of ca. 4:2:1, 2:1:1, and 2:1:1, respectively in 51 to 53 percent yields.Supporting spectral data are presented.
- Ono, Taizo,Inoue, Yoshihisa,Arakawa, Yoshio,Naito, Youichiro,Fukaya, Chikara
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- REACTIVITY OF PHENYLCARBAMOYLDIAZENE TOWARDS 1-AMINOCYCLOPENTENES
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The reactivity of the title enamines has been studied by comparison with the corresponding cyclohexene derivatives.The enchanced electron density at the C-2 atoms leads mainly to bicyclic 1,2,4-triazin-3-one derivatives, irrespective of the amino moiety.A 1:1 enamine adduct was isolated only from 1-(morpholin-4-yl)cyclopentene.
- Benedetti, Fabio,Forchiassin, Mirella,Russo, Claudio,Nitti, Patrizia
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p. 695 - 698
(2007/10/02)
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- THE REACTION OF TRICHLOROSILANE WITH ENAMINES
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A previously unknown reaction of trichlorosilane with enamines has been discovered and a preliminary study done on the possible mechanism.The products of the reaction are a regiospecific trichlorosilyl adduct resulting from addition of the trichlorosilane to the enamine unsaturation and the amine corresponding to simple reduction of the double bond.The addition of the trichlorosilane requires no catalyst and the relative percentages of the products varies in a generally inverse fashion depending on the exact structure of the enamine.Evidence is given to support the assigned structure of the trichlorosilyl species and mechanisms are hypothesized to explain the formation of both products from a common intermediate.Steric rather than electronic factors are suggested as responsible for the observed balance between them.
- Snyder, Dudley C.
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p. 137 - 144
(2007/10/02)
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- The Chemistry of Aryllead(IV) Tricarboxylates. Reaction with Enamines
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The treatment of 1-morhpholinocyclopentene (1a) with p-methoxyphenyllead triacetate (2a) in chloroform provides a simple high-yielding route to 2-(4-methoxyphenyl)cyclopentanone (3a).This arylation reaction of enamines has been investigated with a variety of substrates and a number of aryllead triacetates.The reaction has been found to be very sensitive to steric effects and is thus a useful synthetic method in a relatively small number of cases.Acetoxylation is a major competing reaction with those enamines of cyclic ketones which give a low to moderate yield of arylated product.
- May, George L.,Pinhey, John T.
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p. 1859 - 1871
(2007/10/02)
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- BICYCLIC 1,2-OXAZINE N-OXIDES. DIFFERENT BEHAVIOUR IN RING FISSION BETWEEN SYSTEMS DERIVED FROM 5- AND 6-MEMBERED RING CYCLIC ENAMINES
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1,2-Oxazine N-oxides derived from aminocyclohexenes open into the corresponding nitroalkylated trisubstituted enamines, whereas those derived from aminocyclopentenes give stable tetrasubstituted enamines.Both open-chain systems are easily hydrolyzed to the corresponding χ-nitrocycloalkanones.
- Daneo, S.,Pitacco, G.,Risaliti, A.,Valentin, E.
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p. 1499 - 1504
(2007/10/02)
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- Autoxidation of Cyclic Imines, II. Synthesis of Quinolizidine Derivatives
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Autoxidation of bicyclic imines 4a - d and 18a, b yields Δ9-dehydro-4-quinolizidone derivatives 6 and 20, respectively.Mostly, the quinolizidine compounds are formed via labile α-iminohydroperoxides by fragmentation and rearrangement.For some cases the de
- Schumann, Dieter,Naumann, Anneliese
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p. 1626 - 1635
(2007/10/02)
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