Kinetic Resolution of Acylsilane Cyanohydrins via Organocatalytic Cycloetherification.

An asymmetric cyanation of acylsilanes involving the in-situ formation of chiral acylsilane cyanohydrins followed by their kinetic resolution via organocatalytic cycloetherification is described. The highly enantio- and diastereoselective cycloetherification was crucial for achieving a high efficiency in the kinetic resolution. Consequently, acylsilane cyanohydrins containing a tetrasubstituted chiral carbon atom bearing silyl, cyano, and hydroxy groups were obtained in an enantioenriched form. This protocol therefore offers an efficient catalytic approach to optically active acylsilane cyanohydrins, which exhibit potential as chiral building blocks for the synthesis of pharmaceutically relevant chiral organosilanes.