Ferrier carbocyclization
The Ferrier carbocyclization (or Ferrier II reaction) is an
Several reviews have been published.[3][4]
Reaction mechanism
Ferrier proposed the following reaction mechanism:
In this mechanism, the terminal
Ferrier also reported that the final product, compound 5, could be converted into a conjugated ketone (compound 6) by reaction with acetic anhydride (Ac2O) and pyridine, as shown below.
Modifications
In 1997, Sinaÿ and co-workers reported an alternative route to the synthesis (shown below) that did not involve cleavage of the bond at the anomeric position (the glycosidic bond).[5] In this case, the major product formed had maintained its original configuration at the anomeric position.
Sinaÿ proposed this reaction went through the following transition state:
Sinaÿ also discovered that titanium (IV) derivatives such as [TiCl3(O
In 1988, Adam reported a modification of the reaction that used catalytic amounts of palladium (II) salts, which brought about the same conversion of enol ethers into carbosugars in a more environmentally friendly manner.[7]
Applications
The development of the Ferrier carbocyclization has been useful for the synthesis of numerous natural products that contain the carbocycle group. In 1991, Bender and co-workers reported a synthetic route to pure
References
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- PMID 15186183.
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- doi:10.1039/a802169d.