Results 151 to 160 of about 5,904 (191)

Theory of the Formation and Decomposition of N‐Heterocyclic Aminooxycarbenes through Metal‐Assisted [2+3]‐Dipolar Cycloaddition/Retro‐Cycloaddition

Chemistry – A European Journal, 2013
AbstractThe theoretical background of the formation of N‐heterocyclic oxadiazoline carbenes through a metal‐assisted [2+3]‐dipolar cycloaddition (CA) reaction of nitrones R1CHN(R2)O to isocyanides CNR and the decomposition of these carbenes to imines R1CHNR2 and isocyanates OCNR is discussed.
Alexander S, Novikov, Maxim L, Kuznetsov, Armando J L, Pombeiro   +2 more
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Ti(IV) promoted 1, 3-dipolar cycloaddition of nitrones to vinyl ethers

Tetrahedron, 1998
Abstract The 1, 3-dipolar cycloaddition of nitrones to vinyl ethers is accelerated by Ti(IV) species. The efficiency of the catalyst parallels its complexation capacity. The use of Ti(iPrO)2Cl2 favours the formation of trans cycloadducts, presumably through an endo bidentate complex, in which the metal atom is simultaneously coordinated to the vinyl ...
Pau Bayo´n, Pedro de March, Marta Figueredo, Josep Font   +3 more
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A THEORETICAL STUDY ON THE MECHANISM OF 2:1 1, 3 DIPOLAR CYCLOADDITION REACTIONS

Journal of Theoretical and Computational Chemistry, 2007
The reactions between nitrile oxides and alkenes are of considerable interest in organic synthesis as the resulting heterocycles are versatile intermediates for the synthesis of natural products and biologically active compounds. In this paper, we design a series of reactions of phosphonyl nitrile oxides with acrylonnitrile, which can give 2:1 ...
Wang, J. F., Wei, D. Q., Wang, C. F., Ye, Y., Li, Y. X., Luo, Y., Wang, W. W., Liu, L. Z., Zhao, Y. F.   +8 more
openaire   +1 more source

l,3-Dipolar cycloaddition of unsatu rated ferrocene derivatives with carbonitrileN-oxides

Russian Chemical Bulletin, 1994
3,5-Disubstituted isoxazolines and isoxazoles have been synthesized using 1,3-dipolar cycloaddition of ferrocene derivatives FcCH=CH2, FcCOCH=CH2 and FcC≡CH with aliphatic and aromatic carbonitrileTV-oxides.
G. A. Shvekhgeimer, M Litim
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One-Pot Sequential [3 + 3] Dipolar Cycloaddition of Aldehyde or Ketone and Hydroxylamine with Spirocyclopropyl Oxindole

The Journal of Organic Chemistry, 2018
A Sc(OTf)3-catalyzed highly diastereoselective one-pot sequential [3 + 3] dipolar cycloaddition reaction of aldehyde or ketone, N-alkyl hydroxylamine, and spirocyclopropyl oxindole is developed, allowing facile construction of spirocyclic oxindole-tetrahydro-1,2-oxazines with sufficient structural diversity. The corresponding catalytic enantioselective
Peng-Wei Xu, Chen Chen, Jia-Kuan Liu, Yu-Ting Song, Feng Zhou, Jun Yan, Jian Zhou   +6 more
openaire   +2 more sources

Synthesis of benzosuberone-tethered spirooxindoles: 1-3-dipolar cycloaddition of azomethine ylides and arylidene benzosuberones

Molecular Diversity, 2018
Expedient synthesis of benzosuberone-tethered spirooxindoles was accomplished by a three-component 1,3-dipolar cycloaddition reaction between azomethine ylide (generated in situ) and arylidene benzosuberone. This protocol offers good yield and wide functional group tolerance under mild reaction condition with high regio- and stereoselectivities.
Sundaravel Vivek, Kumar, Gandhi Uma, Rani, Manohar, Divyalakshmi, Nattamai, Bhuvanesh, Shanmugam, Muthusubramanian, Subbu, Perumal   +5 more
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ChemInform Abstract: Trimethylsilyl Triflate‐Promoted (2 + 3)Dipolar Cycloaddition of Nitrones with Allyltrimethylsilane.

ChemInform, 1993
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
D. D. DHAVALE, C. TROMBINI
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1, 3-Dipolar Cycloadditions to Polycyclic Aromatic Hydrocarbons

2002
The results of a 1, 3-dipolar cycloaddition reaction involving polyaromatic hydrocarbons (PAHs) as the dipolarophiles and the 1, 3-dipole formed by the ring-opening of a 5-oxabicyclo[2.1.0]pentane are reported. PAHs such as naphthalene, anthracene, benzanthracene, acenaphthene, phenanthrene, 9, 10-phenanthroline, gave mixtures of endo- (major) and exo-
Margetić, Davor, Warrener, Ronald N., Butler, Douglas N.   +2 more
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Access to functionalised silver(i) and gold(i) N-heterocyclic carbenes by [2 + 3] dipolar cycloadditions

Dalton Transactions, 2012
A new strategy was developed for the modification of silver(I) and gold(I) N-heterocyclic carbenes. Azido groups were grafted and used either by copper-catalysed azide-alkyne cycloaddition before metallation or by thermal and "strain-promoted" 1,3-dipolar cycloaddition after metallation to functionalise the metal-NHCs.
Hospital, Audrey, Gibard, Clémentine, Gaulier, Christelle, Nauton, Lionel, Thery, Vincent, El-Ghozzi, Malika, Avignant, Daniel, Cisnetti, Federico, Gautier, Arnaud   +8 more
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Stereospecificity of 1,.3-dipolar cycloadditions of cyclic nitrones to (E) and (Z)-β-nitrostyrenes

Tetrahedron, 1987
Abstract 3,4-Dihydroisoquinoline-N-oxide (1) reacted readily with (E)-s-nitrostyrene in a regiospecific reaction to give a mixture of 4-nitro-5-phenylisoxazolidines 3a and 4a resulting from endo and exo (with respect to the nitro group) transition states, respectively. This cycloaddition was found reversible under mild conditions. A careful study
Marina Burdisso, Anna Gamba, Remo Gandolfi, Paolo Pevarello   +3 more
openaire   +1 more source