Ferrier rearrangement
The Ferrier rearrangement is an organic reaction that involves a nucleophilic substitution reaction combined with an allylic shift in a glycal. It was discovered by the carbohydrate chemist Robert J. Ferrier.
Mechanism
In the first step, a delocalized allyloxocarbenium ion is formed, typically with the aid of a Lewis acid like indium chloride or boron trifluoride. This ion reacts in situ with an alcohol, yielding a mixture of the α and β 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, the reaction yields a 2,3-unsaturated deoxy sugar.
An analogous reaction with nitrogen as the heteroatom was described in 1984 for the synthesis of the antibiotic substance streptazolin.
