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07:12
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Reaction control in synthetic organic photochemistry: switching between [5+2] and [2+2] modes of cycloaddition
Claudio Roscini1, Kara L Cubbage, Malcolm Berry
1School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
Angewandte Chemie (International Ed. in English)
|October 15, 2009
Abstract
No abstract available in PubMed .
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01:16Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
01:16Cycloaddition Reactions: MO Requirements for Thermal Activation
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01:26Photochemical Electrocyclic Reactions: Stereochemistry
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01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.