A Chiral Cyanohydrin Phosphate for Carbonyl Umpolung—Stereoselective Synthesis of Tertiary Cyanohydrins

High asymmetric induction is achieved in the diastereoselective alkylation of cyanohydrin carbanion 1 (de = 82–94%). The synthesis of optically active tertiary cyanohydrins demonstrates how P-chiral auxiliaries temporarily linked to the substrate through heteroatoms can be used in asymmetric synthesis.