Ferrier-II rearrangement

The key transformation in the synthesis of carbanucleosides, reported by Horvath, was based on the Ferrier-II rearrangement and led to the important derivative ara-cyclohexenyl-A (Fig. 19).32... 

SCHEME 8.31 Synthesis of carba-pyranoses from the product of the Ferrier-II rearrangement. 

SCHEME 8.33 Synthesis of carba-glucasamine using the Ferrier-II rearrangement. 

Unsaturated pyranosides are easily converted into cyclohexane derivatives by a HgCl2-catalyzed rearrangement discovered by Ferrier in 1979 (The Ferrier-II rearrangement) [5]. 

Recently the Ferrier-II rearrangement was used as a key step in the synthesis of unnatural (-) actinobolin. The 5,6-unsaturated compound 72 was prepared by a base-induced elimination of HI from the 6-deoxy-6-iodo-derivative 71 (O Scheme 31) [69]. 

The so-called Ferrier (II) rearrangement is the most common approach to carbasugars, although it requires use of mercury and a reaction time (several hours). Pohl et al. [59], found that the Ferrier (II) rearrangement of 78 into 79 in the presence of palladium dichloride can be performed in less time and with higher yields by use of microwave irradiation rather than conventional heating (Scheme 12.37). 

This reaction was initiaiiy reported by Perrier in 1979. It is a mercury (II) salt -induced or promoted conversion of 5-enopyranosides into cyclohexanones with stereochemical control, by which substituents at positions 3 and 5 are predominantly in a trans relationship. To differentiate from another reaction also discovered by Perrier (called the Perrier Reaction), this reaction is known as the Ferrier-II rearrangement, " Ferrier-II carbocyclization, Perrier carbocyclization, or Ferrier-II reaction. Occasionally, it is also referred to as the Perrier Reaction. Therefore, it is called the Ferrier-II rearrangement in this book. It is useful in the conversion of carbohydrates into carbosugars, myo-inositols, and other natural products. ... 

Systematic investigation of Pd(II)-mediated Ferrier(II) rearrangement for a variety of 6-deoxyhex-5-enopyranosides was reported later, establishing the optimized conditions consisting of the use of 5% PdCl2 in aqueous dioxane solution at 60 °C (Scheme 28). ... 

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