<scp>d</scp>-Gulonolactone as a Synthon for <scp>l</scp>-Noviose: First Preparation of 4-<i>O</i>-Demethyl-<scp>l</scp>-noviofuranose and Related Derivatives
D-Gulonolactone was initially converted in a few steps to the key ester derivative 7 [1-O-benzyl methyl 2,3-O-(1-methylethylidene)-alpha-L-lyxofuranosiduronate]. An appropriate selection of protecting groups enabled transformation of 7 under mild reaction conditions to 4-O-demethyl-L-noviofuranose 9a and related 9b-c. Derivatives 9 were further converted either to L-lyxopyranoses (10a and 10b) or to