Structural study-guided development of versatile phase-transfer catalysts for asymmetric conjugate additions of cyanide.

New phase transfer catalysts are reported for the first example of an organocatalytic asymmetric conjugate addition of cyanide with acetone cyanohydrin. Utilizing an accessible cupreidinium salt and a cyanation reagent suitable for industrial scale, this reaction holds significant promise for practical asymmetric synthesis. Additionally, the reported catalysts were developed as a result of gaining key structural insights via X-ray analysis of a series of catalysts of varying efficiencies and asymmetric induction.