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Ferrier II Reaction
The Ferrier carbocyclization (or Ferrier II reaction) is an organic reaction that was first reported by the carbohydrate chemist Robert J. Ferrier in 1979. It is a metal-mediated rearrangement reaction, rearrangement of enol ether pyrans to cyclohexanones. Typically, this reaction is catalyzed by mercury (element), mercury salts, specifically mercury(II) chloride. Several reviews have been published. Reaction mechanism Ferrier proposed the following reaction mechanism: In this mechanism, the terminal olefin undergoes hydroxymercuration to produce the first intermediate, compound 2, a hemiacetal. Next, methanol is lost and the dicarbonyl compound cyclizes through an attack on the electrophilic aldehyde to form the carbocycle as the product. A downside to this reaction is that the loss of CH3OH at the anomeric position (carbon-1) results in a mixture of α- and β-anomers. The reaction also works for substituted alkenes (e. g. having an -Oacetyl, Ac group on the terminal alk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrier Rearrangement
The Ferrier rearrangement is an organic reaction that involves a nucleophilic substitution reaction combined with an allylic shift in a glycal (a 2,3-unsaturated compound, unsaturated glycoside). It was discovered by the carbohydrate chemist Robert J. Ferrier. Mechanism In the first step, a delocalized allyloxocarbenium ion (2) is formed, typically with the aid of a Lewis acid like indium(III) chloride or boron trifluoride. This ion reacts in situ#Chemistry and chemical engineering, in situ with an alcohol, yielding a mixture of the α (3) and β (4) anomers of the 2-glycoside, with the double bond shifted to position 3,4. Examples Modifications Forming of C-glycosides By replacing the alcohol with a silane, C-glycosides can be formed. With triethylsilane (R'=H), the reaction yields a 2,3-unsaturated deoxy sugar. Nitrogen analogue An analogous reaction with nitrogen as the heteroatom was described in 1984 for the synthesis of the antibiotic substance streptazolin. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
