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

The branched chain protected sugar, ymethyl-2,3;5,-di-O-isopropylidene -D-mannofuranose was specifically benzylated at the primary hydroxyl g roup position by the stannylene procedure (93%). Oxidation with pyridi nium chlorochromate gave in 71% yield ethyl-2,3;5,6-di-O-isopropyliden e-D-mannonolactone which was reduced with 3 equiv of samarium diiodide in oxolane to a 56:44 mixture of the 2-deoxy derivatives, loxymethyl- 2-deoxy-5,6-O-isopropylidene-D-mannono- (5) and -D-glucono-lactones in 83% combined yield. Reduction of lactone 5 with DIBAH in dichlorometh ane gave the protected branched chain sugar, C-benzyloxy-2-deoxy-5,6-O -isopropylidene-D-mannose in 63% yield. In the reduction of ymethyl-2, 3;5,6-di-O-isopropylidene-D-mannolactone and 2-C-hydroxymethyl-D-manno nolactone in water solution, only lactones with the D-manno configurat ion, ydroxymethyl-5,6-O-isopropylidene-D-mannonolactone and 2-deoxy-2- C-hydroxymethyl-D-mannono-(1,5)-lactone, could be isolated or characte rized among the products of the reaction. (C) 1998 Elsevier Science Lt d. All rights reserved.