نتایج جستجو برای: diels alder and 1 3 dipolar cycloaddition reactions

تعداد نتایج: 17429646  

Journal: :Synthesis 2021

Abstract This review updates the field of enantioselective indium-catalyzed transformations all types since 2012. It shows that asymmetric indium catalysis, suits growing demand for greener processes, offers a real opportunity to replace toxic metals in near future. 1 Introduction 2 Allylations, Propargylations, and Allenylations Carbonyl Compounds Derivatives 2.1 Allylations 2.2 Propargylation...

2013
Gunther Seitz Johanna Siegl

Pyridine-C-nucleosides, „Inverse“ [4+2] Cycloadditions, 1,2,4-Triazine-C-nucleosides, 2,,3’-Dideoxy-/?-D-ribofuranosyl-pyridines The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could ...

Journal: :Journal of the American Chemical Society 2010
Julia M Robinson Takeo Sakai Katsuhiko Okano Takafumi Kitawaki Rick L Danheiser

A formal, metal-free, [2 + 2 + 2] cycloaddition strategy is described based on a cascade of two pericyclic processes. The first step involves an intramolecular propargylic ene reaction of a 1,6-diyne to generate a vinylallene, which then reacts in an inter- or intramolecular Diels-Alder reaction with an alkenyl or alkynyl dienophile. Reactions involving unsymmetrical alkenyl and alkynyl dienoph...

Journal: :Molecules 2005
D Branowska

Synthesis of bisfunctionalized unsymmetrical 2,2'-bipyridines 8 or their sulfonyl derivatives 12a,b are described. They were prepared via the Diels-Alder reaction of 1-methyl-4-pyrrolidin-1-yl-1,2,3,6-tetrahydropyridine (6) with 3,3'-bis(methyl- sulfanyl)-5,5'-bi-1,2,4-triazine (1). The reaction leads to the single cycloaddition product 7 which undergoes Diels-Alder reaction with cyclic enamine...

Journal: :Chemical communications 2014
Lucas Henry Christoph Schneider Benedict Mützel Peter V Simpson Christoph Nagel Katharina Fucke Ulrich Schatzschneider

The catalyst-free room temperature iClick reaction of an unsymmetrically 2,3-disubstituted oxanorbornadiene (OND) as a "masked" alkyne equivalent with [Mn(N3)(bpy(CH3,CH3))(CO)3] leads to isolation of a phenylalanine ester bioconjugate, in which the model amino acid is linked to the metal moiety via a N-2-coordinated triazolate formed in a cycloaddition-retro-Diels-Alder (crDA) reaction sequenc...

2009
Haifeng Du

The Diels–Alder (DA) reaction (or “diene synthesis”) between a diene and a dienophile generates two s bonds stereoselectively and up to four chiral centers in a single step to afford six-membered cyclic compounds. This cycloaddition reaction named after Professor Otto Paul Hermann Diels (1876–1954) and his student Kurt Alder (1902–1958) was discovered in 1928 during studies on the reaction of b...

Journal: :Angewandte Chemie 2003
Emily M Stocking Robert M Williams

Nature's repertoire of biosynthetic transformations has recently been recognized to include the Diels-Alder cycloaddition reaction. Evidence now exists that there are enzymes that mediate the Diels-Alder reaction in secondary metabolic biosynthetic pathways. 2002 marked the 100th anniversary of Alder's birth and 75 years since the discovery of the Diels-Alder reaction. It would appear that livi...

Journal: :Angewandte Chemie 2003
Ian S Young Michael A Kerr

Cycloadditions are among the most trusted of chemical transformations available to the synthetic chemist. The predictability of the transition state based on steric and electronic considerations allows for the strategic construction of complex molecular assemblies. While the Diels–Alder reaction has received the most attention, 1,3-dipolar cycloadditions have also maintained a place of prominen...

Journal: :Chemical communications 2014
Jonathan C Moore E Stephen Davies Darren A Walsh Pallavi Sharma John E Moses

The application of electrochemical reactions in natural product synthesis has burgeoned in recent years. We herein report a formal synthesis of the complex and dimeric natural product kingianin A, which employs an electrochemically-mediated radical cation Diels-Alder cycloaddition as the key step.

Journal: :Physical chemistry chemical physics : PCCP 2014
Nicole M Smith K Swaminathan Iyer Ben Corry

Chemical reactions inside carbon nanotubes can yield unusual outcomes. Molecular dynamics simulations show that within the confined space of carbon nanotubes, the 1,4-exo adduct of a Diels-Alder cycloaddition may be produced instead of the 9,10-adduct, which is favoured in bulk. The likely product is highly dependent on the nanotube radius and reactant size.

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