Synthesis of permethylated α-d-mannosylacetic acid, a new type of bioconjugate

A concise stereoselective 3-step conversion of methyl α-d-mannopyranoside to α-d-2,3,4,6-tetra-O-methyl-mannosylacetic acid is described. After methylation of the alcohol functions, an allylation is performed. The resulting alkene undergoes oxidative cleavage to the acid, an alkylated C-sugar, appropriate for attachment to peptides or other drug candidates for solubility enhancement.