to give ( 5 ) (72 %). Opening of the epoxide ring of this r*,1-+4 linked disaccharide derivative with lithium iodide dihydrate gives, in addition to the gluco-altro isomer, the bis-altro compound (7) (56 % yield) as the major product.On reduction with NiCl,/NaBH,['% 51, compound (7) affords methyl 2,6-dideoxy-4-0-(2,6-dideoxy-a-~-ribo-hexo-pyranosy1)-cx-o-ribo-hexopyranoside (9) ['], the glycoside of the terminal disaccharide unit of neo-dig~xin~']. The synthesis has not yet been optimized and the present yield of 34% should be open to considerable improvement. This synthetic approach provides a convenient entry to other oligodeoxyoligosaccharides.Reductive removal of the iodine from ( 5 ) with NiClz/NaBH4''* 51 gives the 2'-deoxy derivative ( 4 b). A series of hitherto unelucidated by-products lowers the yield to 32 %.Epoxide ring cleavage of ( 4 b ) affords not only the gluco-rib0 isomer but mainly the altro-ribo configurated derivative ( 6 b ) (43% yield); the 'H-NMRdatafor its reducing saccharide ring are comparable with those of (7).When subjected to elimination reaction with methyllithium in ether''), (6 b ) smoothly furnishes the disaccharide glycal (8). The derivative (8) (45% yield) represents a disaccharide synthon, comparable with the monosaccharide synthon ( 3 a ) , which permits further synthetic reactions. Addition of methanol to (8) in the presence of N-iodosuccinimide affords (6a), which was transformed into ( 4 a) with sodium methoxide and characterized.