Definition, Betydelse & Anagram | Engelska ordet DIENES

Definition av DIENES

1. böjningsform av diene

Exempel på hur man kan använda DIENES i en mening

• As a subunit of more complex molecules, dienes occur in naturally occurring and synthetic chemicals and are used in organic synthesis.
• In asymmetric dienes one often needs to consider the stereochemistry, which in the case of pericyclic reactions, such as the Cope rearrangement, can be predicted with the Woodward–Hoffmann rules and consideration of the preference for the chair transition state geometry.
• SO inserts into alkenes, alkynes and dienes producing thiiranes, molecules with three-membered rings containing sulfur.
• Butyllithium is principally valued as an initiator for the anionic polymerization of dienes, such as butadiene.
• Related Lewis acid-promoted reactions include as epoxide ring openings and decomplexation of dienes from iron carbonyls.
• Initial studies which demonstrated the transient intermediacy of the seven-, six- and five-membered cycloalkynes relied on trapping of the high-energy alkyne with a suitable reaction partner, such as a cyclic dienes or diazo compounds to generate the Diels–Alder or diazoalkane 1,3-dipolar cycloaddition products, respectively.
• Dicyanoacetylene is a powerful dienophile because the cyanide groups are electron-withdrawing, so it is a useful reagent for Diels-Alder reactions with unreactive dienes.
• In 1978, Rubottom showed that siloxy 1,3 dienes, derived from acyclic or cyclic enones could also serve as substrates for the Rubottom oxidation to forge α-hydroxy enones after treatment with triethyl ammonium fluoride.
• APC catalyzes many organic reactions, such as cross-coupling, nucleophilic addition to dienes, and decomposition of diazo compounds to reactive carbenes.
• Acyclic diene metathesis or ADMET (distinguish from ADME) is a special type of olefin metathesis used to polymerize terminal dienes to polyenes:.
• The approach to conformationally constrained (annulated)-C-glycosyl α- and β-amino acids is based upon the Diels-Alder reaction of pyranose dienes with α- and β-nitro acrylic esters.
• In acyclic dienes, this free rotation leads to diradical reconnection, short-circuiting the di-π-methane process.
• Zirconocene dichloride can be used to cyclise enynes and dienes to give cyclic or bicyclic aliphatic systems.
• As an enone, cyclohexenone is easily adapted to Michael addition with nucleophiles (such as enolates or silyl enol ethers) or, it could be employed by a Diels-Alder reaction with electron-rich dienes.
• As a bifunctional electron-poor dienophile, MBA reacts with electron-rich dienes, such as cyclopentadiene, in Diels–Alder reactions, giving the corresponding norbornene adducts.
• Since then, a variety of substrates have been subject to the rDA, yielding many different dienes and dienophiles.
• A number of dienes have been employed in the reaction, although cyclic, electron-rich dienes such as those found in the cyclopentadiene and furan ring systems are the best 4π systems for this process.
• As exemplified by the Krische allylation, dehydrogenation of alcohol reactants can be balanced by reduction of allenes, dienes or allyl acetate to generate allylmetal-carbonyl pairs that combine to give products of carbonyl addition.

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