SYNTHESIS OF NUCLEOSIDE EPOXYPHOSPHONATES

Reaction of two regioisomeric uridine derivatives, hosphinyl)-5-O-trit yl-beta-D-xylofluranosyl]uracil (4) and sphinyl)-5-O-trityl-beta-D-ara binofuranosyl]uracil (13), with triflyl chloride and 4-pyrrolidinopyri dine (4-PDP) results in formation of the corresponding nucleoside epox yphosphonates. This transformation is immediately useful for confirmin g the trans relationship of the 2'- and 3'-hydroxyl groups in the gemi nal hydroxyphosphonates 3 and 12, and provides access to two new famil ies of nucleoside derivatives that may be of interest for their synthe tic utility and biological properties. Copyright (C) 1996 Elsevier Sci ence Ltd