Staudinger Ketene Cycloaddition: Definition |Mechanism

what is Staudinger ketene cycloaddition?

Staudinger ketene cycloaddition is the organic pericyclic reaction. The thermal [2+2] cycloaddition reaction of ketenes with carbon-carbon, carbon-oxygen, and carbon-nitrogen double bonds is referred to as the Staudinger ketene cycloaddition. Staudinger ketene-imine cycloaddition also known as Staudinger Ketene Cycloaddition.

Mechanism of Staudinger ketene cycloaddition :

As we discussed Staudinger ketene cycloaddition definition, mechanism The Mechanism Staudinger cycloaddition reaction of ketenes with alkenes is believed to occur via a concerted nonsynchronous mechanism, where the approach of the reacting partners is orthogonal. Consequently, the bulkier substituent of the ketene will end up on the sterically more crowded face of the cyclobutanone product.

Two explanations clarify the experimental conclusions:

1. agreeing with the Woodward-Hoffmann rules, the LUMO of the ketene reacts antarafacially with the HOMO of the alkene that reacts superficially.
2. the HOMO of the alkene forms a bond with the Pz orbital of the terminal carbon and the py orbital of the central carbon of the ketene. The reaction of ketenes with carbonyls and imines follows a stepwise mechanism.

Application:

1. β-lactams synthesis
2. cyclopropanaone synthesis
3. preparation of carbon-carbon, carbon-oxygen, and carbon-nitrogen double bonds

Related Reaction:

1. staudinger ketene cycloaddition
2. staudinger cycloaddition
3. cycloaddition of ketene
4. Reactivity and Application of Ketene

References :

1. Asymmetric Synthesis of β-Lactams by Staudinger Ketene-Imine Cycloaddition Reaction
2. Staudinger Ketene−Imine Cycloaddition, RCM Approach to Macrocrocyclic Bisazetidinones
3. The Mechanism of the Ketene−Imine (Staudinger) Reaction in Its Centennial: Still an Unsolved Problem?
4. https://chemistry-reaction.com/ketene
5. https://www.organic-chemistry.org/staudinger-synthesis