Trichloroacetimidate glycosyl donor

Glycosyl donor Trichloroacetimidate formation Glycosyl acceptor0 Reaction conditions Reference... 

Nicolaou s total synthesis of the enediyne antibiotic, calicheamicin 71 [19], (Scheme 12.15 to Scheme 12.19) involves several new aspects in carbohydrate chemistry. The calicheamicin 71 oligosaccharide synthesis began with the construction of the D-ring intermediate from L-rhamnose. Thus, L-rhamnose 112 was converted into the glycosyl donor, trichloroacetimidate 118, through the... 

Trichloroacetimidates as glycosyl donors for generation of anomeric phosphates... 

The great interest in C-glycosyl compounds is reflected in the extensive research in this field (204). Successful investigations with O-glycosyl trichloroacetimidates as glycosyl donors and phenol ethers (199,207,208), silyl enol ethers (205,206), trimethylsilyl cyanide (205,206), and allyltrimethylsi-lane (206) as C-acceptors underline the wide scope of these highly reactive glycosyl donors. 

The first application of (9-glycosyl trichloroacetimidates as glycosyl donors for the glycosylation of an acceptor attached to Merrifield resin was reported by our group in... 

Even controlled-pore glass (CPG) could be successfully employed as solid support with (9-glycosyl trichloroacetimidates as glycosyl donors. Thus, limitations of solvents and reaction temperatures in the glycosylation step, as experienced with the Merrifield resin, are restricted to those observed in solution-phase synthesis. Therefore, regio- and stereocontrol of the glycosylation reactions should be available from well-established solution-phase methodologies. 

These results demonstrate that O-glycosyl trichloroacetimidate-based oligosaccharide synthesis on solid support may eventually become a valuable alternative to solution-phase synthesis because useful experience is available for the selection of the polymer support and choice of the linker system and the glycosyl donor. Further standardization of the building blocks and the protective group pattern will finally provide the yields and the anomeric control in order to successfully plan automated syntheses of oligosaccharides also in a combinatorial manner. 

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