Arabinose and Xylose C -Furanosides

The three previous chapters discussed methods where the selectivities were greater than 3:1 in favor of the gluco -, ido -, or manno - C -furanoside stereoisomer. In this chapter, we will discuss methods that give lower selectivities, or those in which the stereochemistry of the product was unspecified or unassigned. In addition, we will discuss in more depth certain aspects of stereocontrol in C -furanoside synthesis: Competing stereochemical elements and mechanisms exist, and the less selective results may give insight into the complex interplay between factors that determine the experimental outcome. The sections thus have a double heading, one synthetic and one stereochemical. It is our hope that this discussion will shed useful light on the scope and limitations of the different models.