Studies on C-glycosides: XII. Stereoselective synthesis of C-aryl glucosides

2,3,4,6-Tetra-O-benzyl-D-glucopyranose 1-α-(p-nitrobenzoate) reacted with aryl ethers in the presence of Lewis acid to give β-anomers stereoselectively in high yield, but reaction with 1,3-ditrimethylsilyloxybenzene gave α-anomer using BF₃·Et₂O and β-anomer using anhydrous AlCl₃ as catalyst.