Asymmetric Synthesis of cis- and trans-2-Aryl-6-methylpyrans from D-Glucose by Arylation and Inversion of Configuration at the C-2 Position



Asymmetric synthesis of optically active cis- and trans-2-aryl-6-methylpyrans from commercially available tetra-O-acetyl-D-glucopyranosyl bromide has been developed. The reaction proceeds by two important steps. One is the arylation, and the other is deoxygenation at the C-3 position and inversion of configuration at the C-2 position during the preparation of the cis-isomer, when 2-aryl-3-hydroxy-6-(hydroxymethyl)pyrans were treated with trimethylsilyl chloride and sodium iodide.