Glycosidation glycal method

Two major coupling strategies were elaborated for the formation of glycosidic bonds on solid support. Scheme 2.6.1 shows the glycal method developed by Danishefsky et A... 

Scheme 2 Glycosylation method using thioglycosides, n-pentenyl glycosides, glycals, and giycosyi hemiacetais as giycosyi donors.

In rounding out this foray into glycosidation chemistry, it would be most appropriate to close with the glycal method, a procedure that has found numerous applications in total synthesis endeavors. In this general strategy, pioneered by Lemieux and co-workers... 

By use of the acylated glycal method long chain alkyl unsaturated glycosides have been produced from glucose, xylose and rhamnose, and the products were hydrogenated to give 2,3-dideoxy analogues which were examined as thermotropic non-amphiphilic chiral liquid crystals. ... 

The glycal epoxide method turned out to be useful for the construction of complex 2-branched [3-aryl glycosides, which are salient features of the potent antibiotic vancomycin [75a]. Glycal epoxide glycosylation with sodium salts of indoles pro-... 

K. Toshima, T. Ishizuka, G. Matsuo, and M. Nakata, Practical glycosidation method of glycals using montmorillonite K-10 as an environmentally acceptable and inexpensive industrial catalyst, Synlett (1995) 306-308. 

R. J. Patch, H. Chen, and C. R. Pandit, Multivalent templated saccharides Convenient syntheses of spacer-linked 1, l -bis -and 1, 1, 1 "-tris-/i-glycosides by the glycal epoxide glycosidation method, /. Org. Chem., 62 (1997) 1543-1546. 

General Method for the Preparation of 2-Deoxy-2-lodoglycosylbenzenesulfo-namides from Glycals and Its Use as Glycosyl Donors in the Synthesis of 2-Benzene-sulfonamido-2-Deoxy-P-Glycosides... 

Thus, it is of interest to generate oligosaccharides of the type C-B-A in 56, all of which are linked inter-glycosidically by a-(1->4)-bonds. We have previously synthesized various derivatives of the terminal C-B disaccharides employing the Perrier glycosylation approach (59. 60). At that same time we could combine the azide functionalization of glycals (61) with the N-iodosuccin-imide method (1 ) and develop a general approach to 3-... 

Scheme 4 Glycal-based glycosidation reactions, (a) E+ = I(collidine)2Cl04 [11], AModosuc-cinimide [12], PhSeCI [13], PhSCI [14]. (b) Danishefsky method [I5. ...

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