Stereoselective Synthesis of P-Mannosides

This chapter reviews methods for the construction of P-mannosidic linkages. Together with the more popular protocols, less widespread and emerging approaches are also covered in the hope they will stimulate further progress. 

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Hodosi and Kovac reported the highly efficient P-mannosylation, which makes use of mannose-derived 1,2-O-stannylene acetal 15 in combination with an aglycon-derived triflate (Scheme 7.13).58 A remarkable feature of this method is its extreme simplicity. Even totally unprotected mannose can be used as precursor of 15. Undoubtedly, this method can be seen as one of the most facile methods for the stereoselective synthesis of P-mannosides. 

Chapter 8 The Stereoselective Synthesis of P-Mannosides, Seth C. Ennis... 

Crich et al. have used the radical translocation method for the generation of anomeric glycosyl radicals and has also applied this to the stereoselective synthesis of P-mannoside (Scheme 22). Photolysis of the readily available a-mannoside 70, which possesses a C2-bromoethoxy group, with tributyltin hydride in the presence of a catalytic amount of AIBN affords P-mannoside 71 as a major product after acid hydrolysis of the resulting C2-acetal group. The reaction proceeds through the formation of radical 72... 

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