نتایج جستجو برای: diels alder and 1 3 dipolar cycloaddition reactions
تعداد نتایج: 17429646 فیلتر نتایج به سال:
The dual diene/1,3-dipolar character of 1-H-imidazole 3-oxide, HIO 1, allows this compound toparticipate in a competitive Diels-Alder (DA)/1,3-dipolar cycloaddition (13DC) reaction toward C=Sdouble bond of the electro-deficient sulfonyl methane SFM 2. The B3LYP/6-311++G(d,p) calculatedrelative Gibbs free energies indicate that among the studied 13DC and DA reactions, former iscompletely preferr...
the dual diene/1,3-dipolar character of 1-h-imidazole 3-oxide, hio 1, allows this compound toparticipate in a competitive diels-alder (da)/1,3-dipolar cycloaddition (13dc) reaction toward c=sdouble bond of the electro-deficient sulfonyl methane sfm 2. the b3lyp/6-311++g(d,p) calculatedrelative gibbs free energies indicate that among the studied 13dc and da reactions, former iscompletely preferr...
Microcontact printing (μCP) has developed into a powerful tool to functionalize surfaces with patterned molecular monolayers. μCP can also be used to induce a chemical reaction between a molecular ink and a self-assembled monolayer (SAM) in the nanoscale confinement between stamp and substrate. In this paper, we investigate the Huisgen 1,3-dipolar cycloaddition, the Diels-Alder cycloaddition an...
2.1.8. Michael Reaction 2245 2.1.9. Others 2247 2.2. Cyclization Reactions 2248 2.2.1. Carbon Diels−Alder Reactions 2248 2.2.2. Aza-Diels−Alder Reactions 2252 2.2.3. Other Hetero-Diels−Alder Reactions 2255 2.2.4. Ionic Diels−Alder Reaction 2256 2.2.5. 1,3-Dipolar Cycloadditions 2256 2.2.6. Other Cycloaddition Reactions 2258 2.2.7. Prins-type Cyclization 2259 2.3. Friedel−Crafts Acylation and Al...
Abstract The Diels–Alder reaction has long been established as an extremely useful procedure in the toolbox of natural product chemists. It tolerates a wide spectrum building blocks different complexity and degrees derivatization, enables formation six-membered rings with well-defined stereochemistry. In recent years, many total syntheses products have reported that rely, at some point, on use ...
We demonstrate the applicability of sequential Diels-Alder and azide-alkyne [3 + 2] cycloaddition reactions (click chemistry) for the immobilization of carbohydrates and proteins onto a solid surface. An alpha,omega-poly(ethylene glycol) (PEG) linker carrying alkyne and cyclodiene terminal groups was synthesized and immobilized onto an N-(epsilon-maleimidocaproyl) (EMC)-functionalized glass sli...
Cycloaddition reactions represent one of the most powerful processes in organic chemistry. The most common types of cycloaddition reactions are the Diels-Alder (DA) and the 1,3-dipolar cycloaddition reactions (1,3-DCs) which lead to five and six membered rings, respectively. In our ongoing efforts to contribute to the understanding of DA and 1,3-DCs; we studied the following using the B3LYP/6-3...
This review is an endeavor to highlight the progress in the inverse-electron-demand hetero-Diels-Alder reactions of 1-oxa-1,3-butadienes in recent years. The huge number of examples of 1-oxadienes cycloadditions found in the literature clearly demonstrates the incessant importance of this transformation in pyran ring synthesis. This type of reaction is today one of the most important methods fo...
Five-membered carbocyclic rings appear in all classes of organic materials including pharmaceutical agents, polymers, natural products, and catalysts. Accordingly, their preparation has challenged synthetic chemists since the inception of the field. In this regard, [3+2] cycloadditions—both concerted and stepwise—represent convergent strategies for the formation of the cyclopentane nucleus. Dip...
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