A PREPARATION OF PROTECTED 2-DEOXY-2-HYDROXYMETHYL-D-MANNOSE AND -D-GLUCOSE DERIVATIVES NOT INVOLVING ORGANOMETALLIC REAGENTS

Abstract The branched chain protected sugar, 2- C -hydroxymethyl-2,3;5,6-di- O -isopropylidene- d -mannofuranose was specifically benzylated at the primary hydroxyl group position by the stannylene procedure (93%). Oxidation with pyridinium chlorochromate gave in 71% yield 2- C -benzyloxymethyl-2,3;5,6-di- O- isopropylidene- d -mannonolactone which was reduced with 3 equiv of samarium diiodide in oxolane to a 56:44 mixture of the 2-deoxy derivatives, 2- C -benzyloxymethyl-2-deoxy-5,6- O -isopropylidene- d -mannono- ( 5 ) and - d -glucono-lactones in 83% combined yield. Reduction of lactone 5 with DIBAH in dichloromethane gave the protected branched chain sugar, 2- C -benzyloxy-2-deoxy-5,6- O -isopropylidene- d -mannose in 63% yield. In the reduction of 2- C -hydroxymethyl-2,3;5,6-di- O- isopropylidene- d -mannonolactone and 2- C -hydroxymethyl- d -mannonolactone in water solution, only lactones with the d - manno configuration, 2-deoxy-2- C- hydroxymethyl-5,6- O- isopropylidene- d -mannonolactone and 2-deoxy-2- C- hydroxymethyl- d -mannono-(1,5)-lactone, could be isolated or characterized among the products of the reaction.