| 词汇 | alkyne |
| 释义 | alkyne noun[ C ] chemistry specializeduk /ˈæl.kaɪn/ us /ˈæl.kaɪn/ an unsaturated compound of hydrogen and carbon (= one that does not contain the greatest possible number of hydrogen atoms) that has at least one triple bond, for example acetylene炔，炔烃 Chemistry: types of chemical acid salt aerogel albumin alkali metal alkaline alkaloid antioxidant carbohydrate inorganic isopropanol ketone lectin melamine methyl orange monosaccharide mothball propellant saline soluble sulphide Examples of alkynealkyne All reactions proceed via an initial addition of the radical to alkenes, alkynes and aromatic species. Alternatively, acetylene may yield amino acids directly via a conversion of an alkyne to the corresponding aldehyde, which then forms an alpha amino nitrile and eventually an amino acid. Additionally, this compound can by produced through the hydration of an alkyne through mecuric sulfate catalysis. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Using a protected alkyne, as opposed to acetylene gas, prevents further (undesired) coupling reactions and also has the benefit of being a liquid. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The four main categories are (1) nucleophilic attack on an alkene alkyne, or allyl ligand and (2) insertion of the alkene into the metal-amide bond. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Usually, the substrate is an alkene or an alkyne. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The reaction shown below involves an alkyne oxymercuration reaction to generate the requisite ketone. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In the first step of this reaction, a metal acetylide is formed by reaction of the terminal alkyne with the copper salt. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In the uncatalysed reaction the alkyne remains a poor electrophile. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The proton transfer leads to intermediate 4, which undergoes the key fragmentation to alkyne (6) and the corresponding carbonyl compound (7). From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Alkenylalanes, which are easily synthesized with complete stereocontrol through alkyne hydroalumination, transfer the alkenyl unit to a variety of electrophiles. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. It is composed of both alkyne and alkene groups. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Molecules called ene-diynes feature a ring containing an alkene (ene) between two alkyne groups (diyne). From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The most problematic side products of the reaction are due to cyclotetramerization (leading to cyclooctatetraenes) and alkyne dimerization (leading to enynes). From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The conjugated alkyne is reduced to the methyl ester. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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