Related Experiment Video
Updated: Jan 31, 2026

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Ring-Strain-Driven Annulation of Cyclopropenones with Hydrazones via Nucleophilic Phosphine Catalysis
Shan Jiang1, Xiaoqi Yang1, Xiao-Le Han1
1Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education and Hubei Key Laboratory of Catalysis and Materials Science, School of Chemistry and Materials Science, South-Central Minzu University, Wuhan 430074, China.
Abstract:
Herein, we demonstrate a ring-strain-driven annulation of cyclopropenones with hydrazones via simple phosphine catalysis, providing an efficient route to structurally diverse 1,3,4-oxadiazolines and spiro-1,3,4-oxadiazolines under mild conditions. The reaction proceeds through the formation of a reactive α-ketenyl phosphorus ylide intermediate, generated by the interaction of cyclopropenone with a nucleophilic phosphine catalyst. Notably, an intriguing acyl group migration-mediated [3+2] annulation is observed with hydrazones derived from linear ketones, while a ring-opening addition/cyclization cascade takes place with cyclic hydrazones.
More Related Videos
Related Concept Videos
Catalysis
Nucleophiles
Introduction to Mechanisms of Enzyme Catalysis
Nucleophilic Substitution Reactions
In 1896, the German chemist Paul Walden discovered that he could interconvert pure enantiomeric (+) and (-) malic acids through a series of reactions. This conversion suggested the involvement of optical inversion during the substitution reaction. Further, in 1930, Sir Christopher Ingold described for the first time two different forms of nucleophilic substitution reactions, which are known as SN1 (nucleophilic substitution unimolecular) and SN2 (nucleophilic substitution...
Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation

![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)