- Synthesis of 1-organyl-1-(trimethylsiloxy)-2-(dimethylamino)ethenes and new hypervalent silicon compounds based thereon
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1-Organyl-1-(trimethylsiloxy)-2-(dimethylamino)ethenes were synthesized for the first time, and their reactions with trichloro(methyl)silane and trifluoro(phenyl)silane afforded silicon bis-chelates, methylbis-[2-(dimethylamino)-1-(organyl)ethenolato-N,O]
- Gostevskii,Albanov,Vashchenko,Smirnov
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- Modular counter-Fischer?indole synthesis through radical-enolate coupling
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A single-electron transfer mediated modular indole formation reaction from a 2-iodoaniline derivative and a ketone has been developed. This transition-metal-free reaction shows a broad substrate scope and unconventional regioselectivity trends. Moreover, important functional groups for further transformation are tolerated under the reaction conditions. Density functional theory studies reveal that the reaction proceeds by metal coordination, which converts a disfavored 5-endo-trig cyclization to an accessible 7-endo-trig process.
- Chung, Hyunho,Kim, Jeongyun,Gonzalez-Montiel, Gisela A.,Cheong, Paul Ha-Yeon,Lee, Hong Geun
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supporting information
p. 1096 - 1102
(2021/01/26)
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- Superelectrophilic chemistry of amino-nitriles and related substrates
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The superacid-promoted Houben/Hoesch reactions of amino-nitriles and related compounds have been studied. The nitriles form dicationic electrophiles and react with benzene in fair to good yields (12-95%). The intermediate iminium ions may also be reduced to the benzylic amines by NaBH4 or H 2.
- Raja, Erum K.,Klumpp, Douglas A.
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experimental part
p. 4494 - 4497
(2011/07/08)
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- Tandem catalytic allylic amination and [2,3]-stevens rearrangement of tertiary amines
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We have developed a catalytic allylic amination involving tertiary aminoesters and allylcarbonates, which is the first example of the use of tertiary amines as intermolecular nucleophiles in metal-catalyzed allylic substitution chemistry. This process is
- Soheili, Arash,Tambar, Uttam K.
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supporting information; experimental part
p. 12956 - 12959
(2011/10/08)
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- Asymmetric synthesis of β-dialkylamino alcohols by transfer hydrogenation of α-dialkylamino ketones
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Transfer hydrogenation of representative aryl and heteroaryl dialkylaminomethyl ketones with formic acid-triethylamine, catalyzed by RuCl[(R,R)-TsDPEN](η-p-cymene), produces the corresponding β-dialkylamino alcohols, 97-99% ee, in 50-73% yields. Asymmetric synthesis of (R)-macromerine, 98% ee, the cactus Coryphantha macromeris alkaloid, is also described.
- Kosmalski, Tomasz,Wojtczak, Andrzej,Zaidlewicz, Marek
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experimental part
p. 1138 - 1143
(2009/09/27)
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- Requirements for selective hydrophobic acceleration in the reduction of ketones
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(Chemical Equation Presented) Reductions of various quaternized hydrophobic β-keto amines were performed in water and in methanol using borohydride anions carrying hydrophobic groups. The most important requirement of the substrate to permit hydrophobical
- Biscoe, Mark R.,Uyeda, Christopher,Breslow, Ronald
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p. 4331 - 4334
(2007/10/03)
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- Method for preparing chiral diphosphines
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The invention concerns a method for preparing a compound of formula (1) wherein: A represents naphthyl or phenyl optionally substituted; and Ar1, Ar2independently represent a saturated or aromatic carbocyclic group, optionally substituted.
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- Hydrophobically Directed Selective Reduction of Ketones
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Three hydrophobic borohydrides carrying phenyl, pentafluorophenyl, and β-naphthyl groups were used to reduce ketones in water and in methanol. With ketones carrying phenyl, naphthyl, or biphenyl substituents, there was preferential reduction in methanol o
- Biscoe, Mark R.,Breslow, Ronald
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p. 12718 - 12719
(2007/10/03)
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- Substituent Effects on the Strength of C-C Bonds, 14. - Kinetic and Thermodynamic Stability of 2,3-Bis(dialkylamino)-1,4-diketones - Energy of Stabilization of α-Dialkylamino α-Carbonylalkyl Radicals with Capto-dative Substituents
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The equilibrium constants and rate constants for the dissociation of the 2,3-bis(dialkylamino)-1,4-diketone diastereomers meso- and DL-7a and 7b were measured over a temperature range of 40 deg C.From the enthalpies of dissociation ΔHDiss and ethalpies of activation ΔH(excit.) and the strain enthalpies of 7 the bond dissociation enthalpies BDE(C-C) of 7 were determined.By comparison with the dissociation enthalpies of Ct-Ct alkanes the change of these BDEs(C-C) by the capto-dative substitution was determined to be 85.4 kJ mol-1 (20.4 kcal mol-1).The heats of formation ΔHf0(g) of a series of amino ketones 8 were determined from their heats of combustion and their heats of evaporation.From the ΔHf0(g) values in combination with MM2 calculations of their strain enthalpies strain-free increments CHn2-n> with n = 0, 1, 2 were derived and geminal interaction enthalpies in the ground states were obtained thereof.The radical stabilization enthalpy RSE of 6 was deduced from the ΔBDE(C-C) values and the ground state effect to be 73.6 kJ mol-1 (17.6 kcal mol-1).From these data and the radical stabilization enthalpies RSE of α-aminoalkyl radicals (4.2 kJ mol-1) and α-carbonyl radicals (28.9 kJ mol-1) a synergetic radical stabilization enthalpy of 40.5 kJ mol-1 (9.7 kcal mol-1) is deduced.This number combines "extra" resonance stabilization and general inductive or anomeric geminal substituent interaction in the radicals.The crystal structure of meso-7a has been determined by X-ray diffraction methods. - Key Words: C-C Bond cleavage, kinetics of / Heats of formation / Radicals, stability of / Capto-dative effect / Geminal substituents, energetic interaction of
- Welle, Frank,Verevkin, Sergej P.,Keller, Manfred,Beckhaus, Hans-Dieter,Ruechardt, Christoph
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p. 697 - 710
(2007/10/02)
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- Kinetic Resolution of Racemic β-Hydroxy Amines by Enantioselective N-Oxide Formation
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A practical and fairly general procedure for the kinetic resolution of β-hydroxy tertiary amines is described.It involves the selective oxidation of one enantiomer to the N-oxide by using tert-butyl hydroperoxide (TBHP) and a chiral catalyst prepared by mixing 2 parts of titanium isopropoxide (Ti(O-i-Pr)4 and 1.2 parts of either (+)- or (-)-diisopropyl tartrate (DIPT).The product N-oxide and the unreacted amino alcohol are then easily separated by trituration or organic/aqueous solvent extractions, and chromatography is avoided.The oxidations are generally run to 60percent conversion and the results for 21 different amino alcohols are given.The enantiomeric excess of the slow reacting (i.e., recovered) enantiomer of the amino alcohol often exceeds 90percent.Among the more interesting substrates are the natural product ubine (95percent ee) (18), N-methylephedrine (95percent ee) (15), N-methylpseudoephedrine (93percent ee) (16), cis-2-(dimethylamino)cyclohexanol (>95percent ee) (13), trans-2-(dimethylamino)cyclohexanol (92percent ee) (12), N-benzylbevantolol (85percent ee) (27), and N-benzylpropranolol (32percent ee) (21).The latter two examples are β-blocker precursors.One of the most important characteristics of this new route to enantiomerically pure β-hydroxy amines is its predictability.Thus, in all cases examined to date, when using (+)-DIPT the absolute configuration at the carbinol center in the slow reacting enantiomer is always the same .A study of how the titanium/tartrate ratio, water, catalyst/substrate ratio, and temperature effect this reaction is discussed.
- Miyano, Sotaro,Lu, Linda D.-L.,Viti, Steven M.,Sharpless, K. Barry
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p. 4350 - 4360
(2007/10/02)
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- MANNICH REACTION UNDER HIGH PRESSURE. DIMETHYLAMINOMETHYLATION OF KETONES WITH BIS(DIMETHYLAMINO)METHANE UNDER MILD CONDITIONS
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Dimethylaminomethylation of ketones with bis(dimethylamino)methane takes place cleanly in methanol at room temperature in the kiro bar region.
- Matsumoto, Kiyoshi,Hashimoto, Shiro,Otani, Shinichi,Amita, Fujitsugu,Osugi, Jiro
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p. 585 - 590
(2007/10/02)
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- Base-catalysed Rearrangements involvung Ylide Intermediates. Part 8. The Preparation and Some Reactions of Stable Ammonium Ylides
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The carbonyl-stabilised ammonium ylides (3), (12a-n), and (14a-c) were obtained from the reaction of the corresponding ammonium halides (1), (13a-n), and (15a-c) with sodium hydroxide in water or aqueous methanol.The ylides, which were characterised by their molecular formulae and spectroscopic properies, regenerated quaternary ammonium bromides on treatment with hydrobromic acid.In general the reactions of the ammonium ylides resemble those of the corresponding sulphonium ylides.Thus ylides having a suitable migrating group (ArCH2) undergo a Stevens rearrangement on heating, and other ylides fragment to give a tertiary amine and products containing the PhCOCH grouping.A number of ylides reacted with dimethyl acetylenedicarboxylate to give the furans (32).The ylides (14b and c) with phenyl isocyanate gave the phenylcarbamoyl-substituted ylides.
- Jemison, Robert W.,Mageswaran, Sivapathasuntharam,Ollis, W. David,Sutherland, Ian O.,Thebtaranonth, Yodhathai
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p. 1154 - 1164
(2007/10/02)
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- INVESTIGATIONS IN THE AREA OF AMINES AND AMMONIUM COMPOUNDS. CLIII. STEVENS REARRANGEMENT UNDER THE INFLUENCE OF SODIUM
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The Stevens rearrangement was realized in ammonium salts containing a phenacyl, alkoxycarbonylmethyl, acetonyl, or cyanomethyl group in addition to a β,γ-unsaturated group by the action of metallic sodium.
- Kocharyan, S. T.,Razina, T. L.,Ogandzhanyan, S. M.,Babayan, A. T.
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p. 1256 - 1260
(2007/10/02)
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