Related Experiment Video
Updated: Jul 7, 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
Parallel Synthesis of Pyrazolone-Fused Cinnolines by the Palladium-Catalyzed [4 + 2] Annulation of Pyrazol-3-ones
Wei-Jung Chiu1, Ting-Yen Chu1, Indrajeet J Barve2
1Department of Applied Chemistry, National Yang-Ming Chiao-Tung University, 1001, Ta-Hseuh Road, Hsinchu 300-10, Taiwan.
Abstract:
The synthesis of pyrazolone-fused cinnolines from pyrazol-3-ones and α,γ-substituted allenoates via a palladium-catalyzed C-H activation/annulation cascade was developed. Mechanistic studies revealed the course of the reaction. Initially, N-acyl-valine ligand-assisted ortho-C-H activation gives ortho-alkenylated intermediate. Subsequent cyclopalladation and migratory insertion of allenoate give a seven-membered palladacycle. Reductive elimination finally furnishes pyrazolone-fused cinnolines.
More Related Videos
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
10:42Preparation of N-2-alkoxyvinylsulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines
Published on: January 3, 2018
Related Concept Videos
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Cycloaddition Reactions: Overview
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement