The synthesis of l-gulose and l-xylose from d-gluconolactone

l-Gulose, an essential component for the antibiotic and antitumor activities of bleomycin A2, was synthesized in 47% yield from d-glucono-1,5-lactone. The effective cleavage of acetonides by SnCl2 in the presence of tert-butyldimethylsilyl ethers was of importance in the course of synthesis. Elaboration of d-glucono-1,5-lactone that includes a step of oxidative degradation by Dess–Martin periodinane also afforded a respectable yield of l-xylose.