Related Experiment Video
Updated: Nov 16, 2025
![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
Tandem [2 + 2] Cycloaddition/Rearrangement toward Carbazoles by Visible-Light Photocatalysis
Cheng-Juan Wu1,2, Wen-Xiao Cao1,2, Bin Chen1,2
1Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, the Chinese Academy of Sciences, Beijing 100190, P. R. China.
Abstract:
Reported herein is the first example of the synthesis of carbazoles via oxidative cyclization of 3-alkenylindoles with styrenes under visible light. The irradiation of a catalytic amount of [Ir(dtbbpy)(ppy)2][PF6] as the photocatalyst enables various 3-alkenylindoles and styrenes to undergo tandem [2 + 2] cycloaddition/rearrangement, thereby leading to carbazole derivatives in good to excellent yields under aerobic conditions. Mechanistic studies reveal that photoinduced energy transfer followed by electron transfer is responsible for the tandem reaction.
Related Concept Videos
Cycloaddition Reactions: Overview
Cycloaddition Reactions: MO Requirements for Thermal Activation
Cycloaddition Reactions: MO Requirements for Photochemical Activation
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Thermal and Photochemical Electrocyclic Reactions: Overview
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
