Related Experiment Video
Updated: Jan 20, 2026
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
Synthesis of Spirobicyclic Pyrazoles by Intramolecular Dipolar Cycloadditions/[1s, 5s] Sigmatropic Rearrangements
Christine A Dimirjian1, Marta Castiñeira Reis1, Edward I Balmond1
1Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States.
Abstract:
The formation of fused pyrazoles via intramolecular 1,3-dipolar cycloadditions of diazo intermediates with pendant alkynes is described. A subsequent thermal [1s, 5s] sigmatropic shift of these pyrazole systems resulted in a ring contraction, forming spirocyclic pyrazoles. The limitations of this rearrangement were explored by changing the substituents on the nonmigrating aromatic ring and by using substrates lacking an aromatic linkage to the propargyl group.
Related Concept Videos
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement
Intermolecular vs Intramolecular Forces
14:11Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
05:07Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
10:54Detection of Retrotransposition Activity of Hot LINE-1s by Long-Distance Inverse PCR
