Ferrier rearrangements

Lewis-acid (such as BF3 OEt2, SnCU, rc.)-promoted rearrangement of unsaturated carbohydrates. 

Recent review by Gomez et al. [11] covers very extensively all important aspects of the Perrier rearrangement. The stereoselectivity of the reactions and the mechanism of catalyst action effects on the yields of the rearrangement products were discussed. The practical aspects of selected rearrangement reactions with their detailed synthetic utilization and application were described as well. 

Among many reports of the classical Perrier rearrangement, Ghosh and coworkers [12] reported the synthesis of 2-C-acetoxymethyl glycals as convenient starting templates for the rearrangement. The rearrangement reaction with aliphatic 

SCHEME 93 Application of aza-Cope rearrangement to synthesizing 1-amino-substituted sugars. 

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SCHEME 5. Ferrier rearrangement catalyzed by acid zeolites. 

SCHEME 9. Ferrier rearrangement by glycosidation of 3,4-di-O-acetyl-L-rhamnal with several alcohols catalyzed by Montmorillonite K-10. 

S. Sowmya and K. K. Balasubramanian, Microwave induced Ferrier rearrangement, Synthetic Commun., 24 (1994) 2097-2101. 

B. Shanmugasundaram, A. K. Boseb, and K. K. Balasubramanian, Microwave-induced, montmorillonite KlO-catalyzed Ferrier rearrangement of tri-O-acetyl-D-galactal Mild, eco-friendly, rapid glycosidation with allylic rearrangement, Tetrahedron Lett., 43 (2002) 6795-6798. 

A. K. Misra, P. Tiwari, and G. Agnihotri, Ferrier rearrangement catalyzed by HC104-Si02 Synthesis of 2,3-unsaturated glycopyranosides, Synthesis, 2 (2005) 260-266. 

P. Tiwari, G. Agnihotriand, and A. K. Misra, Synthesis of 2, 3-unsaturated C-glycosides by HC104-Si02 catalyzed Ferrier rearrangement of glycals, Carbohydr. Res., 340 (2005) 749-752. 

Microwave-assisted Wolff [183], Curtius [184], and Ferrier rearrangements [185] have also been reported, albeit employing microwave irradiation under uncontrolled conditions. 

Among numerous other studies, Ferrier rearrangement is notable since it proceeds well (72-83%) upon irradiation of neat reactants [93],... 

A concluding example illustrates an interesting reaction whose outcome is analogous to the Ferrier rearrangement but involves a conjugate addition of alcohols to... 

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. 

An interesting reaction has been developed by Hanessian to reach the same type of branched-chain derivatives, without the need to prepare enones [62], The enol acetate 38 (Scheme 18), easily prepared by Ferrier rearrangement of 2-acetoxyglucal, underwent... 

AUylic systems are interesting substrates for the investigation of new methods of C-C bond formation. Some of these methods have been adapted to the carbohydrate field. Enopyrano-sides are often crystalline compounds readily available, for example, using Ferrier rearrangement of tri-0-acetyl glycals with alcohols or its variants with carbon nucleophiles. 

N. Chida, M. Ohtsuka, K. Ogura, and S. Ogawa, Synthesis of optically active cyclohexenones from carbohydrates by catalytic Ferrier rearrangement, Bull. Chem Soc. Jpn. 64 2118 (1991). 

V. Bolitt, C. Mioskowski, S. G. Lee, and J. R. Falck, Direct preparation of 2-deoxy-D-gluco-pyranosides from glucals without Ferrier rearrangement, J. Org. Chem., 55 (1990) 5812-5813. 

J. C. Lopez, A. M. Gomez, S. Valverde, and B. Fraser-Reid, Ferrier rearrangement under nonacidic conditions, J. Org. Chem., 60 (1995) 3851-3858. 

C. Booma and K. K. Balasubramanian, A novel tandem Ferrier rearrangement cyclisation, Tetrahedron Lett., 34 (1993) 6757-6760. 

The synthesis of the C9-C15 subunit 64 commenced with the cyclocondensation of aldehyde 67 and diene 68 to provide dihydropyrone 66 (Scheme 16) [118]. A Luche reduction [119, 120] and acid-mediated Ferrier rearrangement gave lactol 69 [121], installing the 03-04 (Z)-trisubstituted olefin. A further five steps... 

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... 

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