Raney nickel 1-thio sugars

More recently, Wolfrom and Foster found that the d and l enantio-morphs of methyl 3,4-0-isopropylidene-2-0-[(methylthio)thiocarbonyl]-/3-arabinop3Tanoside rearrange, on pyrolysis, to the appropriate 2-methyl-thio)carbonyl] esters. The reductive desulfurization of methyl 3,4-0-isopropylidene-2- S - [(methylthio)carbonylj - 2 - thio -/3 - d - arabinopyranoside (LXVIII) with Raney nickel, to afford a low yield of methyl 2-deoxy-3,4-0-isopropylidene-/3-D-erj/intramolecular rearrangement to LXVIII, and the relationship of the transformation to the Chugaev reaction was discussed. 

A later-developed method to obtain amines from azides consists in their reduction with propane-1,3-dithiol,employing ethyldiisopropylamine as a base. The transformations reported proceeded rapidly and resulted in, 2-trans selectivity. Unverzagt described the reduction of the azido heptasaccharide 221 by this dithiol method, to give exclusively the p amine 222. In contrast, reduction of 221 by Raney nickel resulted in both anomers 222 and 223, with p a = 7 3. A corresponding reduction of the azido octasaccharide gave a 52% yield however, a low yield of 35% was observed in the reduction of the thio sugar azide 68 with propane-1,3-dithiol... 

Deoxygenation, of sugars can also be achieved by way of thio-sugar precursors, which can be desulphurized with Raney nickel or sodium in liquid ammonia or tributyltin hydride. This approach has been used to synthesize methyl 2-amino-2,3-dideoxy-4,6-0-isopropylidene-a-D-ribo-hexopyranoside (278) from the 3-S-phenylthio-a-D-allopyranoside obtained when the 3-triflate (279) reacted with sodium benzenethiolate at 5°C—in this instance, desulphuration was best achieved with sodium in liquid ammonia. ... 

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