Open-Chain Juxtacyclic Substrates

Open-Chain Juxtacyclic Substrates a. Role of the Solvent 

S 2 mechanism. The carbanion formed at a attacks the a carbon resulting in an inversion of configuration at the carbon bearing the halogen. 

Protic Medium, The stereospecificity which is characteristic of an aprotic medium is no longer observed when the rearrangement is carried out in a protic solvent such as methanol. The trans derivative 6 gives a 1 1 mixture of the acids 7 and 8. We will discuss two interpretations which were given in order to explain this behavior, namely, House s interpretation that suggests that the cyclopropanone is solvated, and Tchoubar s hypothesis that it is the enolate 1 which is influenced by the solvent. 

On the other hand, cleavage of the cyclopropanone bond opposite to the carbonyl generally requires acidic conditions. The same is true for the 

Solvation of enolate 1 is a hypothesis which is perfectly coherent with the 

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When the cyclopropanone is more stable than the zwitterion the reaction will give the rearrangement products (step b) (examples substrates bearing few substituents, juxtacyclic open-chain compounds, or those of the type... 

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