ABSTRACT

I. TRIFLATE SYNTHESIS AND REACTIVITY A. Reactivity of Sulfonlc Acid Esters In Substitution Reactions Substitution reactions that involve organic compounds use a variety of leaving groups. Those leaving groups frequently used, however, represent only a small subset of the larger collection. Table l contains a list of some common leaving groups with their reactivities expressed as the relative rates of solvolysis of the corresponding 1-phenylethyl derivatives [l]. Among the groups listed in Table l, esters of sulfonic acids are the most reactive, and consequently, are particularly attractive choices where displacement from carbohydrates is concerned. (SN2 substitution reactions of carbohydrates are often difficult to achieve and, even when possible, can require vigorous reaction conditions.) Another reason for selecting sulfonic acid esters as leaving groups for substitution reactions of carbohydrates is that these esters are easily prepared from compounds containing hydroxyl groups.