Enantioselective CC Bond Formation as a Result of the Oriented Prochirality of an Achiral Aldehyde at the Single‐Crystal Face upon Treatment with a Dialkyl Zinc Vapor

Show your best face: An achiral pyrimidine-5-carbaldehyde that forms an achiral crystal () with enantiotopic (001) and () faces underwent enantioselective addition of iPr2Zn to the single exposed enantiotopic surface to give highly enantiomerically enriched S and R secondary alcohols (see scheme). The absolute configuration of the alcohol product correlated with the orientation of the prochiral aldehyde in the achiral crystal lattice.