The synthesis of D-arcanose

Abstract Oxidation of methyl 4,6- O -benzylidene-2-deoxy-α- D - lyxo -hexopyranoside ( 3 ) with ruthenium tetroxide gave the 3-ketone 4 in high yield. Treatment of ketone 4 with methylmagnesium iodide gave predominantly methyl 4,6- O -benzylidene-2-deoxy-3- C -methyl-α- D - xylo -hexopyranoside (5), which was converted into the 3- O -methyl derivative ( 6 ). The reaction of compound 6 with N -bromosuccinimide afforded methyl 4- O -benzoyl-6-bromo-2,6-dideoxy-3- C -methyl-3- O -methyl-α- D - xylo -hexopyranoside (7) in high yield. Compound 7 was converted, by catalytic debenzoylation and reductive debromination, into methyl α- D -arcanoside (9). Acid-catalyzed hydrolysis of glycoside 9 gave D -arcanose ( 10 ). Configurational studies support the 2,6-dideoxy-3- C -methyl-3- O -methyl- xylo -hexose structure for arcanose.