The intrinsic stereoselectivity of the cyanide addition to β-hydroxyketones in the presence of 18-crown-6 or ZnI2 is lower than that previously reported. However, the reaction bears a practical value in that syn β-hydroxycyanohydrins and anti 2, 4-dihydroxyamides can be diastereoselectivity obtained in reasonable yields in a one-pot procedure. The high de's initially reported were due to the work-up procedure, where the HCl converted much faster ...
