In a solvent system of CH2Cl2-H2O contg. Bu4N+OH-, monobenzylation occurs at a much higher rate than does dibenzylation due to the lower concn. of alcoholate anions in the aq. layer. Methyl 4,6-O-benzylidene-a-D-glucopyranoside reacted with PhCH2Br in CH2Cl2 and aq. NaOH contg. Bu4N+ HSO4- for 48 h to give the 2,3-dibenzyl-, 2-benzyl-, and 3-benzyl- derivs. in 6, 54, and 20% yields, resp. [on SciFinder (R)]