Ferrier-rearranged products

Alternatively, Pd(0) adds oxidatively to the double bond of a glycal derivative resulting in the formation of a ir-allyl complex, which may react with carbon nucleophiles to give C-glycosides with a double bond between C(2) and C(3).26 A rt-allyl complex may also be formed starting from a Ferrier rearrangement product (2,3-unsaturated sugar derivative).22... 

The natural products (+)-calystegine and its enantiomer have been synthesized from D-glucose via the Ferrier rearrangement product 198. Ring expansion of the cyclopropane derivative 199 gives 200, converted to either 201 or 202, precursors to the natural product 203 or its enantiomer 204 respectively (Scheme 48). [preliminary report see Vol. 26, p. 314-5, ref. 73]. 

These examples and many others illustrate the ongoing fascination with the Ferrier rearrangement. The growing catalog of catalysts and subtle variations in outcomes that are associated with these serve to enhance the practical utility of this reaction in glycoside and natural product synthesis. 

The highly oxygenated sesquiterpene paniculide A was synthesized by N. Chida et al. starting from D-glucose. The key step to construct the substituted cyclohexane subunit of the natural product involved the Type II Ferrier rearrangement. 

Danishefsky and coworkers employed two hetero Diels-Alder reactions in a total synthesis of the ansa bridge of rifamycin S (Scheme 52) The first cyclocondensation reaction uses the trimethylsilyloxy diene (14) and a preincubated solution of 3-(benzoyloxy)-2-methyl-1-propanal (188) with an excess of TiCU in CHCh. The product is exclusively the syn-ACF pyrone (189). Through a Ferrier rearrangement and a sequence of oxidation-reduction steps followed by functional group manipulations aldehyde (190) is obtained. 

In the Ferrier rearrangement, the orientation of the hydroxy group at C-5 in the product cyclohexanone depends on the conformation of the starting alkene, illustrated in Scheme 10. A synthesis of the aminocyclohexanone (41) from 2-amino-2-deoxy-D-glucose... 

The Ferrier carbocyclization reaction is a reliable transformation of 5-enopyranosides into carbocycles. As shown in Scheme 12.12 (the carbon numberings in substrates and products have been changed the numbering of substrates is based on the nomenclature of carbohydrates, and the numbering of products is that of cyclohexanones), irrespective of the kinds of substituents and patterns of stereochemistry in the substrates, the rearranged products (15 and 42-46) were obtained in moderate to good yields with relatively high diastereoselectivity. An exception is a reaction of a 4-deoxy-5-enopyranoside derivative, which resulted in a low yield of product 47. 

D-Glucose is the starting material for a total synthesis of (-)-mesembranol 34 in which a key step is the Ferrier rearrangement to provide the cyclohexenone 33 (Scheme 9)M Although the natural product contains 3 chiral centres, only one of these is derived from those of D-glucose. 

To demonstrate the versatility of the Petasis-Ferrier rearrangement. Smith has exploited this reaction in the total syntheses of several natural products, such as (+)-phorboxazole A, [29, 30] (+)-zampanolide, [31-33] and (+)-spongistatin [34]. 

The CAN-catalyzed addition of thiophenol to anhydroglucal 7, in both the absence and presence of sodium iodide, was studied. In both cases, the a-glycosides and Ferrier-rearranged a-glycosides were the major products. The Ferrier products were the major products when sodium iodide was added. 

Starting from 1,5-anhydro-2,3,4-tri-0-benzoyl-6-deoxy-D-ura >/ o-hex-1 -enitol (48), an unusual approach to the synthesis of disaccharides of serogroup A and D has applied the allylic rearrangement glycosylation procedure of Ferrier [127] to obtain an a-D-< rj//zTO-hex-2-enopyranosyl residue in the disaccharide 49a. Reduction of the 2-enopyranose double bond gave both the paratose (ribo) 49b and tyvelose (arabino) 49c products [28]. 

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