Related Experiment Video
Updated: Mar 21, 2026
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Cyclization of 4-Phenoxy-2-coumarins and 2-Pyrones via a Double C-H Activation
Katrina Mackey1, Leticia M Pardo1, Aisling M Prendergast1
1Department of Chemistry and Analytical & Biological Chemistry Research Facility, University College Cork , College Road, Cork, Ireland.
Abstract:
Aryl-heteroaryl coupling via double C-H activation is a powerful transformation that avoids the installation of activating groups. A double C-H activation of privileged biological scaffolds, 2-coumarins and 2-pyrones, is reported. Despite the rich chemistry of these molecular frameworks, the yields are very good. Excellent regioselectivity was achieved on the pyrones. This methodology was applied to the synthesis of flemichapparin C in three steps. Isotope effect experiments were carried out, and a mechanism is proposed.
More Related Videos
07:36Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
06:34Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS
Published on: June 20, 2014
Related Concept Videos
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Benzene to Phenol via Cumene: Hock Process
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Cycloaddition Reactions: Overview