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Updated: Jul 6, 2026
11:45
Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Alkylzinc hydrazides: self-assembly of hexanuclear ring systems in acetonitrile
Mark R J Elsegood1, Carl Redshaw
1Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|March 14, 2008
Summary
No abstract available in PubMed .
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01:10Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism
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Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
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02:38Electrophilic Addition to Alkynes: Halogenation
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Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
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As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
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