TETRA-N-PROPYLAMMONIUM TETRA-OXORUTHENATE(VII) - A REAGENT OF CHOICE FOR THE OXIDATION OF DIVERSELY PROTECTED GLYCOPYRANOSES AND GLYCOFURANOSES TO LACTONES

2,3,4,6-Tetra-O-benzyl-D-glucopyranose, 2,3,5-tri-O-allyl-D-ribofurano se, 2,3,5-tri-O-allyl- and -tri-O-benzyl-D-arabinofuranose, and 2-deox y-3,5-di-O-allyl-D-erythro-pentofuranose were oxidized to their corres ponding lactones 6-10 by dimethyl sulfoxide activated by oxalyl chlori de, pyridinium dichromate in the presence of molecular sieves and acet ic acid, and tetra-n-propylammonium tetra-oxoruthenate(VII) using 4-me thylmorpholine N-oxide as cooxidant. With the latter reagent, analytic ally pure lactones were obtained in 83-98% yield. A multistep preparat ion of -tri-O-benzyl-2-deoxy-D-arabino-hexono-1,5-lactone (14) from -b enzyl-1,5-anhydro-2-deoxy-D-arabino-hex-1-enitol (65% overall yield) i s described.