An improved synthesis of methyl (methyl -2,3-O-isopropylidene-beta-D-a
llofuranosid)uronate (7) from methyl propylidene-beta-D-ribo-pentodial
do-1,4-furanoside (6), using vinylmagnesium bromide in the key step, a
nd its application to the total synthesis of uracil polyoxin C (1) are
described.