Position and enantioselective dihydroxylation of 2-hydroxymethyl- and 2-hydroxyethyl-butadiene derivatives using bis-cinchona alkaloid catalysts

The asymmetric dihydroxylation of p-methoxybenzoate esters or p-methoxyphenyl ethers of 2-hydroxymethyl-1,3-butadienes or 2-hydroxyethyl-1,3-butadienes proceeds with excellent position and enantioselectivity using bis-cinchona alkaloid catalysts. The regioselectivity of these reactions is strongly influenced by binding interactions between the aromatic ether or ester group and the catalyst as predicted from a previously proposed transition state model.